chapter 25 · 2006-05-05 · hazardous materials: recognition and identification christopher...

HAZARDOUS MATERIALS: RECOGNITION AND IDENTIFICATIONHAZARDOUS MATERIALS: RECOGNITION AND IDENTIFICATIONChristopher Hawley, Baltimore County Fire Department (Ret.)

OUTLINEOUTLINEObjectivesIntroductionLocation and OccupancyPlacards, Labels, andMarkings

Other Identification SystemsContainersSensesChemical and PhysicalProperties

Lessons LearnedKey TermsReview QuestionsEndnotesAdditional Resources

CHAPTER

25

Photo courtesy of Baltimore County Fire Department

754 ■ CHAPTER 25

STREET STORYWhile the news media tends to focus on the large and spectacular, the reality isthat every day the fire service responds to literally hundreds of hazardousmaterials–related incidents. These incidents usually do not get much attentionbecause they are small in scope and are handled with a minimal amount of firedepartment resources. Common examples include natural gas leaks and flam-mable and combustible liquid spills.

We have an old saying in the HAZMAT community that the initial ten min-utes of an incident will dictate the tone for the first hour of an incident.Clearly, the actions—or inactions—of the first responders will set the tone foran incident. I think back to two incidents in my career that reinforce this point.

The first incident involved an engine company being sent to investigate acall regarding an unknown liquid spilled along a highway. Upon arrival, theengine company officer found a very viscous red liquid spilled along a longdistance of a road, apparently from the rear of a tractor-trailer. Unsure of theidentity and the potential hazard of the liquid, the officer requested a HAZMATunit to respond to the scene and provide assistance. Using their monitoring anddetection equipment, responders were eventually able to determine that the liq-uid posed no hazard to the community. In fact, the unknown liquid was eventu-ally identified as strawberry syrup! Although the officer took some ribbingfrom his peers, he clearly made the proper decisions to ensure the safety ofboth his personnel and the community.

In the second incident, a police officer was called to provide assistance to apublic works road crew that had discovered what appeared to be a 5-poundportable fire extinguisher wrapped in duct tape with a fuse on the top.Although he believed it to be a hoax, the officer still requested the response ofthe fire department bomb squad. After conducting a thorough risk assessmentand requesting the additional assistance of a HAZMAT response team, thebomb squad was able to determine that the perceived hoax was, in fact, anactual explosive device. When the device was disrupted (i.e., blown up) by thebomb squad, it made a lasting impression on the police officer!

In both of these instances, recognition and identification by the first respon-ders set the tone for the incident. If you do not know what to do, isolate thearea, deny entry, and call for help.

—Street Story by Gregory G. Noll, Emergency Planning and ResponseConsultant, Hildebrand and Noll Associates, Lancaster, Pennsylvania

HAZARDOUS MATERIALS: RECOGNITION AND IDENTIFICATION ■ 755

OBJECTIVESAfter completing this chapter, the reader should beable to:

Identify the nine hazard classes as defined byDOT.*Identify the hazards associated with each hazardclass.Identify the standard occupancies wherehazardous materials may be used or stored.Identify the standard container shapes and sizesand common products.Identify both facility- and transportation-relatedmarkings and warning signs.Identify the standard transportation types forhighway and rail.Explain the use of the NFPA 704 system.Explain the use of transportation containers inidentifying possible contents.Explain the location of emergency shutoffs onhighway containers.Explain the importance of understandingchemical and physical properties of hazardousmaterials.

INTRODUCTIONThis chapter is of primary importance to the emer-gency responder.

opening photo, firefighters are using proper PPE buttaking a considerable risk to rescue a live victim.More information on this rescue and risk is pro-vided in the case study in Chapter 28. Althoughfires have killed hundreds before, these types offires are rare. Hazardous materials incidents havekilled thousands and injured countless more. In1984 a release of methyl isocyanate in Bhopal,India, killed more than 2,000 and injured thousandsmore. This incident was the basis for the EmergencyPlanning and Community Right to Know Act(EPCRA) because several facilities in the UnitedStates use this material.

Four basic clues to recognition and identificationare (1) location and occupancy; (2) placards, labels,and markings; (3) container types; and (4) thesenses. A mere suspicion in any of these areasshould be enough to place a first responder on guardfor the possibilities of a chemical release and itsassociated hazards, Figure 25-1.

LOCATION ANDOCCUPANCY

*Reader’s Note: In the hazardous materials section, NFPA 1001requires that the student receive hazardous materials training ateither the Awareness level or the Operations level. The informationin this text covers both levels and in some cases exceeds the Oper-ations level. All of this information is important for firefighters’survival. See the discussion on NFPA standards and OSHA’sHAZWOPER for more information on Awareness and Operationslevel training.

Figure 25-1 The four basic clues to recognition andidentification are location and occupancy; placards,labels, and markings; container types; and senses.

Safety It is through recognition and identifi-cation (R&I) that firefighters can impact theirability to stay alive.

The inability to recognize the potential for chemi-cals to be present and the inability to identify thechemical hazard can place firefighters in severedanger. Firefighting is inherently dangerous, but theresponse to a hazardous materials release creates anadditional risk. Not only can there be immediateeffects from some materials, but multiple exposurescan have far-reaching effects. As depicted in the

Caution The size of the community does notimpact the potential for hazardous materials;every community has hazardous materials.

756 ■ CHAPTER 25

Most communities have a gas station or a hardwarestore. The average home has a large amount of haz-ardous materials that can cause enormous problemsduring a response. In rural communities, farmspresent unique risks due to the storage of pesticidesand fertilizers, Figure 25-2. All of these locationsand occupancies provide the potential for the stor-age of hazardous materials. In general, the moreindustrialized a community is, the more hazardousmaterials the community will contain. Communi-ties adjacent to industrialized areas or along majortransportation corridors (interstate highways, rail,

water) may also have the same hazards becausethese materials can travel through the community,Figure 25-3. Buildings that typically store haz-ardous materials include hardware stores, hospitals,auto part supply stores, dry cleaners, manufacturingfacilities, print shops, doctors’ offices, photo labs,agricultural supply stores, semiconductor manufac-turing facilities, electronics manufacturing facili-ties, light to heavy industrial facilities, marineterminals, rail yards, airport terminals and fuelingareas, pool chemical stores, paint stores, hotels,swimming pools, and food manufacturing facilities.

Figure 25-2 Agricultural supply stores have a large quantity of hazardousmaterials, including pesticides, herbicides, and fertilizers. In many cases theyalso have fuels, including propane.

Figure 25-3 If a community has a road, the potential for a hazardous materials incidentexists. One of the most common chemical releases is a gasoline spill.


PLACARDS, LABELS,AND MARKINGS

This section examines the first concrete evidence ofthe presence of hazardous materials. A number ofsystems are used to mark hazardous materials con-tainers, buildings, and transportation vehicles. Thesystems result from laws, regulations, and stan-dards, and in some cases from a combination of thethree. As an example the Building Officials Con-ference Association (BOCA) code, which has beenadopted as a regulation in local communities,requires the use of the NFPA 704 marking system,Figure 25-4, for certain occupancies.

PlacardsThe most commonly seen item for identifying the location of hazardous materials is the placard. TheDepartment of Transportation (DOT) regulates themovement of hazardous materials (“dangerousgoods” in Canada) by air, rail, water, roadway, andpipeline by means of 49 CFR 170-180. After meetingcertain guidelines a shipper must placard a vehicle towarn of the storage of chemicals on the vehicle, anexample of which is shown in Figure 25-5.

Figure 25-4 The NFPA has developed a system for identifying potentialchemical hazards in a building. The system is known as NFPA 704.

Note The quantity of hazardous materials thatmust be carried in order to require placarding is1,001 pounds, unless it is one of five classes ofmaterials that require placarding at any amount.

Figure 25-5 The DOT requires some shippers of haz-ardous materials to provide placards to warn respon-ders of chemicals that may be on the truck.

Table 25-1 and Table 25-2 provide further expla-nations of the placarding system.

The DOT has established a system of nine hazardclasses that uses more than twenty-seven placards toidentify a shipment. The idea behind these hazardclasses is to provide a general grouping to a ship-ment and to provide some basic information regard-ing the potential hazards. The placards, like the oneshown in Figure 25-6, are 103⁄4 inches by 103⁄4 inches

758 ■ CHAPTER 25

TABLE 25-1

TABLE 25-2

Materials That Require Placarding at Any Amount (DOT Table 1)

HAZARD CLASS OR DIVISION PLACARD TYPE

1.1 Explosives 1.1

1.2 Explosives 1.2

1.3 Explosives 1.3

2.3 Poison gas

4.3 Dangerous when wet

5.2 (Organic peroxide, type B, liquid or solid, temperature controlled) Organic peroxide

6.1 (Inhalation hazard Zone A or B) Poison inhalationhazard

7 (radioactive label III only) Radioactive

Materials That Require Placarding at 1,001 Pounds(DOT Table 2)

CLASS OR DIVISION PLACARD TYPE

1.4 Explosives 1.4

1.5 Explosives 1.5

1.6 Explosives 1.6

2.1 Flammable gas

2.2 Nonflammable gas

3 Flammable

COMBUSTIBLE LIQUID COMBUSTIBLE

4.1 Flammable solid

4.2 Spontaneously combustible

5.1 Oxidizer

5.2 (Other than organic peroxide, type B, liquid or organic Organic peroxideperoxide solid, temperature controlled)

6.1 (Other than inhalation) Poison

6.1 (PG III) Keep away from food

6.2 None

8 Corrosive

9 Class 9

ORM-D None


and are to be placed on four sides of the vehicle.Labels are 39⁄10 inches by 39⁄10 inches and are affixednear the shipping name on the container. Labels, forthe most part, are smaller versions of placards andare designed to provide warnings about the packagecontents. There are labels for some materials that donot have or require placards.

The system is designed so that materials desig-nated by the DOT as potentially harmful to theenvironment, humans, and animals are easily identi-fied. Such a material has to present an unreasonablerisk to the safety, health, or property upon contact.The DOT has two placarding tables, which arecalled Table 1 and Table 2. The materials that are onTable 1 (as shown in Table 25-1) are those that aremost hazardous and require the use of a placard no

Figure 25-6 “Corrosive” placard. Not to scale.

Note Placards are useful because they takeadvantage of four ways to communicate thehazard class they represent.

TABLE 25-3

TABLE 25-4

matter what the quantity being shipped. The materi-als in DOT Table 2 (as shown in Table 25-2) arethose that require placarding at 1,001 pounds. Thecriteria establishing this 1,001-pound rule are notclearly defined, but responders should be aware thata spill of 999 pounds of a material can be as haz-ardous as 1,001 pounds. The shipper uses the haz-ardous materials tables (49 CFR 172.504) todetermine which labels and placards are required.The tables may also list a packing group for thematerial, which indicates the danger associated withthe material being transported.

Packaging Group I: Greatest dangerPackaging Group II: Medium dangerPackaging Group III: Minor danger

Packaging groups are only assigned to classes 1, 3through 6, 8, and 9 as shown in Table 25-3 throughTable 25-6. These are determined based on flashpoints, boiling points, and toxicity.

Packing GroupsFLAMMABILITY—CLASS 3 FLASH POINT BOILING POINTPACKING GROUP (PG) (°F) (°F)

I � 95

II � 73 � 95

III � 73 and � 141 � 35

Division 2.3, Poisonous GasHAZARD ZONE INHALATION TOXICITY—LETHAL CONCENTRATION

(LC50)*

Hazard Zone A LC50 less than or equal to 200 ppm

Hazard Zone B LC50 greater than 200 ppm and less than or equal to 1,000 ppm

Hazard Zone C LC50 greater than 1,000 ppm and less than or equal to 3,000 ppm

Hazard Zone D LC50 greater than 3,000 ppm and less than or equal to 5,000 ppm

*LC50 is the lethal concentration to 50 percent of an exposed population (gases).

760 ■ CHAPTER 25

They have distinct colors, they have a pictureat the top of the triangle depicting a representa-tion of the hazard, they state the hazard class inthe middle of the placard, and they display thehazard class and division number in the bottomtriangle.

As an example the placard shown in Figure 25-6is black and white, which represents the corrosiveclass. The top of the placard has a picture of a handand a steel bar being eaten away by the corrosivematerial being poured on it, the middle of the plac-ard states corrosive, and at the bottom the classnumber 8 shows.

The DOT also requires the addition of a four-digit number, known as the United Nations/NorthAmerica (UN/NA) identification number, either ona placard or on an adjacent orange strip. This iden-tifies a bulk shipment of over 119 gallons and pro-vides an identity to the material. A tank truckcarrying gasoline, which would be considered abulk shipment, would display a flammable placard1

with the number 1203 either in the middle of theplacard or on an orange strip adjacent to the placardas shown in Figure 25-7. This provides an addi-tional bit of information to the responder, becausewithout the UN/NA number, the only informationprovided would be that a flammable liquid was onboard.

The nine hazard classes and subdivisions2 arediscussed next.

Class 1, Explosives (Figure 25-8)Division 1.1. Mass explosion hazard, such asblack powder, dynamite, ammonium perchlorate,detonators for blasting, and RDX explosives.Division 1.2. Projectile hazard, such as aerialflares, detonating cord, detonators for ammuni-tion, and power device cartridges.Division 1.3. Fire hazard or minor blast hazard.Examples include liquid-fuel rocket motors andpropellant explosives.Division 1.4. Minor explosion hazard, whichincludes line throwing rockets, practice ammu-nition, detonation cord, and signal cartridges.Division 1.5. Very insensitive explosives, whichdo have mass explosion potential but during nor-

Figure 25-7 There are three ways to signify the four-digit ID number for bulk shipments. The most com-mon is for the four-digit DOT identification number tobe placed in the middle of the placard.

TABLE 25-5

TABLE 25-6

Division 6.1, Packing Materials That Are Toxic by a RouteOther Than Inhalation

PACKING GROUP ORAL TOXICITY— DERMAL TOXICITY— INHALATION BY LETHAL DOSE (LD50)* LETHAL DOSE (LD50) DUSTS AND MISTS (MG/KG) (MG/KG) LC50 (MG/L)

I �5 �40 �0.5

II �5, �50 �40, �200 �0.5, �2

III Solids: �50, �200 �200, �1,000 �2, �10Liquids: �50, �500

*(LD50) Lethal dose to 50 percent of the exposed population (solids and liquids).

Division 6.1, Toxic Materials Poisonous by InhalationPACKING GROUP VAPOR CONCENTRATION AND TOXICITY

I (Hazard Zone A) V �500 LC50 and LC50 200 mL/m3


Safety Incidents involving explosives can bevery dangerous, especially when involved in fire.

mal shipping would not present a risk. Ammo-nium nitrate and fuel oil (ANFO) mixtures arean example of this division.Division 1.6. Also very insensitive explosivesthat do not have mass explosion potential. Mate-rials that present an unlikely chance of ignitionare part of this grouping.

Figure 25-8 “Explosive” placards and labels.

Making a tactical decision to attack a fire involvingexplosives can endanger the responders, especially ifthe fire has reached the cargo area of the vehicle. Therecommendations in the Emergency ResponseGuidebook (ERG) should be followed, paying partic-ular attention to the isolation and evacuation distances.When explosives are involved in traffic accidents notinvolving fire, the actual threat is minimized depend-ing on the circumstances. As long as the explosiveswere transported legally and as they were intended tobe transported, the responders should face little danger.Some cities require an escort and that the explosivesbe transported at nonpeak hours. Spilled explosivematerials may present a health hazard if inhaled orabsorbed through the skin.

ANFO Explosion On November 29, 1988, anengine company from the Kansas City, Missouri,Fire Department was dispatched to a reportedpickup truck fire. While en route to the incidentthe engine company was told to use cautionbecause explosives were reportedly involved.When they arrived they found that they had twoseparate fires, one in the pickup truck and theother in a trailer. The first engine began to extin-guish the fire in the pickup truck and requested asecond engine for assistance as well as the dis-trict battalion chief. They attempted to contactthe second engine to warn them of the explo-sives on fire on top of the hill. The secondengine arrived and began to attack the fire ontop of the hill. They requested the assistance ofthe first engine and also requested a squad forwater. From the radio communications with thebattalion chief the crews thought that the explo-sives had already detonated.

The battalion chief was a quarter of a mileaway where he had stopped to talk with thesecurity guards when the explosives detonated.The explosion moved the chief’s car 50 feet andblew in the windshield. The blast was heard for60 miles and damaged homes within 15 miles.The chief requested additional assistance andstaged the responding companies. There was areport that there were more explosives on thehill that had not yet detonated. Luckily the chiefdid not let any other responders into the scenebecause shortly after pulling back, a secondexplosion went off, reportedly larger than thefirst one.

The next morning a team of investigatorswent to the site to begin the investigation. Theydiscovered that six firefighters were killed in theblast and the explosion was very devastating.Only one engine was recognizable; the otherwas reduced to the frame rail. The first blast wasfrom 17,000 pounds of an ammonium nitrate,fuel oil, and aluminum mixture. It also had3,500 pounds of ANFO. The second explosioninvolved 30,000 pounds of the mixture. The useof ANFO is common throughout the UnitedStates for blasting purposes. Ammonium nitrateis commonly used as a fertilizer in the agricul-tural business and is used on residential lawns.The Oklahoma City Alfred P. Murrah FederalBuilding explosive was devised of ammoniumnitrate and nitromethane, very similar to ANFO.The World Trade Center bombing in 1993 usedan explosive made up primarily of urea nitrateand three cylinders of hydrogen. Both explo-sives are comparable to each other, and whenthey are used improperly the results can bedevastating.

762 ■ CHAPTER 25

INHALATIONHAZARD

INHALATIONHAZARD

Figure 25-9 “Gas” placards and labels.Figure 25-10 “Flammable” and “Combustible”placards and label.

Class 2, Gases (Figure 25-9)Division 2.1. Flammable gases that are ignitableat 14.7 psi in a mixture of 13 percent or less inair, or have a flammable range with air of at least12 percent regardless of the lower explosivelimit (LEL). Propane and isobutylene are exam-ples of this division.Division 2.2. Nonflammable, nonpoisonous,compressed gas, including liquefied gas, pres-surized cryogenic gas, and compressed gas insolution. Carbon dioxide, liquid argon, andnitrogen are examples.Division 2.3. Poisonous gases that are known tobe toxic to humans and would pose a threat dur-ing transportation. Chlorine and liquidcyanogen are common examples of this divi-sion. Gases assigned to this division are alsoassigned a letter code identifying the material’stoxicity levels. These levels are discussed fur-ther in the section on toxicology. The hazardzones associated with this division are:

Hazard Zone A: LC50 less than or equalto 200 ppm

Hazard Zone B: LC50 greater than 200 ppmand less than or equal to 1,000 ppm

Hazard Zone C: LC50 greater than1,000 ppm and less than or equal to3,000 ppm

Hazard Zone D: LC50 greater than3,000 ppm and less than or equal to5,000 ppm

The hazard zones are a quick way to determine howtoxic a material is. Hazard Zone A materials are moretoxic than Hazard Zone B materials, and so forth. Theshipping papers will identify these by the addition ofPoison Inhalation Hazard (PIH) Zone A, B, C, or D.

Class 3, Flammable Liquids (Figure 25-10)Flammable liquids have a flash point of less than141°F. Gasoline, acetone, and methyl alcohol areexamples.Combustible liquids are those with flash pointsabove 100°F and below 200°F. The DOT allowsliquids with a flash point of 100°F to beshipped as a combustible liquid. Examplesinclude diesel fuel, kerosene, and various oils.

Caution The difference between a flammableliquid and a combustible liquid is based on thematerial’s flash point. The flash point is the tem-perature of the liquid at which there could be aflash fire if an ignition source is present. The fireservice usually refers to a flammable liquid as onethat has a flash point of 100°F or lower. The DOTclassifies any liquid with a flash point of 141°F orlower as being a flammable liquid. Any liquid witha flash point greater than 141°F is consideredcombustible by the DOT. It can be confusingwhen using the terms flammable and com-bustible to describe a liquid material. Most refer-ences, with the exception of the DOT, use 100°Fas the criteria for flammable and combustible.


Figure 25-11 Class 4 placards and labels.


Class 4, Flammable Solids (Figure 25-11)Division 4.1. Includes wetted explosives, self-reactive materials, and readily combustible solids.Examples include magnesium ribbons, picricacid, explosives wetted with water or alcohol, orplasticized explosives.Division 4.2. Composed of spontaneously com-bustible materials including pyrophoric materi-als or self-heating materials. An example iszirconium powder.Division 4.3. Dangerous-when-wet materials arethose that when in contact with water can igniteor give off flammable or toxic gas. Calcium car-bide when mixed with water makes acetylenegas, which is very flammable as well as unsta-ble in this form. Sodium is another example of amaterial that when wet can ignite explosively.Lithium and magnesium are not as explosive assodium but will react with water. Magnesium ifon fire will react violently if water is used in anattempt to extinguish the fire.

Class 5, Oxidizers and Organic Peroxides(Figure 25-12)

Division 5.1. The class assigned to materialsthat have the ability to produce oxygen, whichin turn increases the chance of fire, and duringfires make the fire burn more intensely. Ammo-nium nitrate and calcium hypochlorite areexamples.Division 5.2. The organic peroxides, which havethe ability to explode or polymerize, which ifcontained is an explosive reaction. These arefurther subdivided into seven types:

Type A: Can explode upon packaging.These are DOT forbidden, whichmeans they cannot be transported andmust instead be produced on site.

Type B: Can thermally explode,considered a very slow explosion.

Type C: Neither detonates nordeflagrates rapidly, and will notthermally explode.

Type D: Only detonates partially ordeflagrates slowly, and has medium orno effect when heated and confined.

Type E: Shows low or no effect whenheated and confined.

Type F: Shows low or no effect whenheated and confined, and has low or noexplosive power.

Type G: Is thermally stable and is desensitized.

Class 6, Poisonous Materials (Figure 25-13)Division 6.1. Materials that are so toxic to humansthat they would present a risk during transporta-tion. Examples include arsenic and aniline.Division 6.2. Composed of microorganisms ortheir toxins, which can cause disease to humansor animals. Anthrax, rabies, tetanus, and botulismare examples.

Hazard zones are associated with Class 6 materials:

Hazard Zone A: LC50 less than or equal to 200 ppmHazard Zone B: LC50 greater than 200 ppm andless than or equal to 1,000 ppm.

Class 7, Radioactive Materials (Figure 25-14)Those materials determined to have radioactiveactivity at certain levels.Although there is only one placard, the labelsshown in Figure 25-14 are further subdivided

764 ■ CHAPTER 25

Figure 25-14 Class 7 placards and labels. Figure 25-16 Class 9 placards and label.

Figure 25-15 Class 8 placards and label.

into Radioactive I, II, and III, with level IIIbeing the highest hazard. The designation I, II,or III is dependent on two criteria: the transportindex and the radiation level coming from thepackage. The transport index is the degree ofcontrol the shipper is to use and is based on acalculation of the radiation threat the packagepresents. Responders should understand that apackage labeled radioactive may be emittingradiation. These emissions of radiation are legalwithin certain guidelines:

Radioactive I label—less than 0.005 mSv/hr(0.5 mR/hr)Radioactive II label—more than Radioactive Iand less than 0.5 mSv/hr (50 mR/hr)Radioactive III label—more than Radioactive IIand less than 2 mSv/hr (200 mR/hr)

Packages emitting more than 2 mSv/hr requirespecial handling and transportation and are sub-ject to additional regulations.

Class 8, Corrosives (Figure 25-15)Includes both acids and bases, and is describedby the DOT as a material capable of causingvisible destruction in skin or corroding steel oraluminum. Examples include sulfuric acid andsodium hydroxide.

Class 9, Miscellaneous Hazardous Materials(Figure 25-16)

A general grouping that is composed of mostlyhazardous waste. Dry ice, molten sulfur, andpolymeric beads are examples that would use aClass 9 placard.

INHALATIONHAZARD

PG III

INFECTIOUS SUBSTANCEIN CASE OF DAMAGE OR LEAKAGE

IMMEDIATELY NOTIFYPUBLIC HEALTH AUTHORITY

IN U.S.A.NOTIFY DIRECTOR - CDC

ATLANTA, GA1-800-232-0124

PG III

INFECTIOUS SUBSTANCEIN CASE OF DAMAGE OR LEAKAGE

IMMEDIATELY NOTIFYPUBLIC HEALTH AUTHORITY

IN U.S.A.NOTIFY DIRECTOR - CDC

ATLANTA, GA1-800-232-0124

INHALATIONHAZARD



Figure 25-17 “Dangerous” placard.

Figure 25-18 “Harmful” placard.

This is known as a catch-all category. If a sub-stance does not fit into any other category andpresents a risk during transportation then itbecomes Class 9.

Other Placards and LabelsThe Dangerous placard is used when the shipperis sending a mixed load of hazardous materials.If the shipper sends 2,000 pounds of corrosivesand 2,000 pounds of a flammable liquid, then in-stead of displaying two placards the shipper candisplay a Dangerous placard, as shown in Fig-ure 25-17. If any of the items exceeds2,205 pounds and is picked up at one location,then in addition to the Dangerous placard theshipper is to display the placard for the materialthat exceeds the 2,205 pounds.The Stow Away from Foodstuffs placard indi-cates that a poisonous material is being trans-ported, but it is not poisonous enough to meet therules to be placarded as a poison; most arePG III. Chloroform is an example that would usea placard like the one shown in Figure 25-18.“Other Regulated Material—Class D” (ORM-D) is a classification that is left over from a pre-vious DOT regulation. It is a subdivision thatincludes ammunition and consumer commodi-ties, such as cases of hair spray. The packagewill have the printing “ORM-D” on the outsideof the package. The previous regulation used tohave ORM-A through ORM-E, but these arenow grouped together in Class 9, MiscellaneousHazardous Materials.

“Marine Pollutant” is displayed on shipments that,if the material were released into a waterway,would damage the marine life, Figure 25-19.Elevated temperature material will have a“HOT” label either to the side of or on the plac-ard, as shown in Figure 25-20, if it meets one ofthe following criteria:

Is a liquid above 212°F.Is a liquid that is intentionally heated and hasa flash point above 100°F.Is a solid at 464°F or above.“Infectious Substances” is a label like the oneshown in Figure 25-21 that is sometimes usedon the outside of trucks. It is not required bythe DOT but may be required by other agen-cies such as Health and Human Services or astate agency.The Fumigated placard, like the one shown inFigure 25-22, is used when a trailer or railcarhas been fumigated with a poisonous material.This placard is commonly found near portswhere containers are frequently fumigatedafter arriving from a foreign port.

A white square background as shown in Fig-ure 25-23 is used in the following situations:

On the highway for controlled Radioactive IIIshipments

MARINE POLLUTANT

Figure 25-19 “Marine Pollutant” marking.

Figure 25-20 “Hot” placard.

766 ■ CHAPTER 25

DANGER

DO NOT ENTER

THIS UNIT IS UNDER FUMIGATIONWITH APPLIED ON

FUMIGANT NAME

DATE

TIME

Figure 25-22 “Fumigation” marking.

Caution Given the restrictions of many cities,bridges, and tunnels where hazardous materialsare not allowed, many trucks are probably notcarrying the proper designations.

Figure 25-23 White-squared “Flammable Gas”placard.

On rail for:Explosives 1.1 or 1.2Division 2.3 Hazard Zone A (poison gas)materialsDivision 6.1 Packing Group I Hazard Zone A(poison)

Division 2.1 (flammable gas) in a DOT 113tank carDivision 1.1 or 1.2, which is chemical ammu-nition that also meets the definition of a mate-rial that is poisonous by inhalation

Problems with the Placarding SystemThe placarding system relies on a human to deter-mine the extent of the load, determine the appropri-ate hazard classes, and interpret difficultregulations to determine if a placard is required.The placard then must be affixed to all four sides ofthe vehicle before shipment. Placards are onlyrequired for shipments that exceed 1,001 pounds,except for materials listed in Table 25-1, whichrequire placarding at any amount. It is suspectedthat 10 to 20 percent of the trucks traveling thehighway are not placarded at all or not placardedcorrectly.

Figure 25-21 “Biohazard” labels.

A placard can come off during transport andlegally may not have to be immediately replaced.The fact that an incident involves a truck or trainshould alert the first responder to the potential forhazardous materials, and when a placard is involvedextra precautions should be taken.


Streetsmart Tip A tractor trailer wasinvolved in an accident and had jackknifed inBaltimore County, Maryland. The HAZMAT teamwas called to assist with the fuel spill. Uponarrival the HAZMAT team inquired as to thecontents of the truck and was told by the firstresponders that the truck was carrying rockingchairs. While working to control the fuel leak theHAZMAT team noticed a greenish blue liquidcoming from the front of the trailer, where it hadbeen damaged in the accident. They locatedthe driver and asked him about the contents ofthe trailer, which did not display a placard. Thedriver stated he was carrying rocking chairs,which is what the shipping papers showed theload to be.

The crews opened the back of the trailer toinspect the cargo and found rocking chairs.Upon closer inspection of the front of the truck,several drums were noticed in the very front ofthe trailer. When the driver was confronted bythe HAZMAT team and a state trooper, thedriver confessed he had picked up a load ofunknown waste from his first stop. He did notknow the contents of the drums and it took sev-eral days to determine the exact contents of thedrums. Beware—it is unlikely that someone try-ing to evade the law will mark the shipmentappropriately.

Figure 25-24 The DOT adds the “Poison—Inhalation Hazard” label to those materialsthat present severe toxic hazards.

LabelsLabeling and Marking SpecificsPackage markings must include the shipping nameof the material, the UN/NA identification number,and the shipping and receiving companies’ namesand addresses. Packages that contain more than areportable quantity (RQ) of a material must alsobe marked with an RQ near the shipping name.Packages that are listed as ORM-D materials shouldbe marked as such. Some packages with liquids inthem must use orientation arrows. Materials thatpose inhalation hazards must affix an InhalationHazard label next to the shipping name, as shown inFigure 25-24. Hazardous wastes will be marked“Waste” or will use the EPA labeling system toidentify these packages.

Labels are identical to placards, other than theirsize.

Note Materials that have more than one haz-ard may be required to display a primary hazardlabel and a subsidiary label.

The primary label will have the class and divisionnumber in the bottom triangle, while the subsidiarylabel will not have the number at all, as shownin Figure 25-25. As an example, the material

768 ■ CHAPTER 25

Figure 25-26 NFPA 704 system placard.

acrylonitrile, inhibited, is required to be labeled“Flammable” with a subsidiary label of “Poison.”

OTHER IDENTIFICATIONSYSTEMS

There are several other identification systems thatare used in private industry to mark facilities andcontainers. Military shipments and pipelines arealso marked to provide a warning as to the potentialfor hazardous materials. Much like the transporta-tion system the warnings are a clue to the potentialpresence of hazardous materials that could causeharm to the responders.

NFPA 704 SystemOne of the other more common systems used to iden-tify the presence of hazardous materials is the NFPA704 system. This system is designed for buildings,not transportation, and alerts the first responders tothe potential hazards in and around a facility. Thesystem is much like the placarding system and relieson a triangular sign that is divided into four areas, asshown in Figure 25-26. The four areas are dividedby color as well, and use a ranking system to identifyseverity. The four areas and colors are:

Health hazard—blueFire hazard—redReactivity hazard—yellowSpecial hazards—white

The system uses a ranking of 0–4 with 0 presentingno risk and a ranking of 4 indicating severe risk.The specific listings are discussed next.

HealthThis listing is based on a limited exposure to thematerials using standard firefighting protectiveclothing as the protective clothing for the exposure.

4—Severe health hazard3—Serious health hazard2—Moderate hazard1—Slight hazard0—No hazard

FlammabilityThis listing pertains to the ability of the material toburn or be ignited.

4—Flammable gases, volatile liquids, py-rophoric materials

3—Ignites at room temperature2—Ignites when slightly heated1—Needs to be preheated to burn0—Will not burn

ReactivityThis listing is based on the material’s ability to react,especially when shocked or placed under pressure.

4—Can detonate or explode at normalconditions

3—Can detonate or explode if stronginitiating source is used

2—Violent chemical change iftemperature and pressure are elevated

1—Unstable if heated0—Normally stable

Special HazardsThis listing is used to indicate water reactivity andoxidizers, which are included in the NFPA 704 sys-tem. In some cases other symbols may be used suchas the tri-foil for radiation hazards, “ALK” for alka-lis, and “CORR” for corrosives. In the presence ofthe slashed W there is also an accompanying rank-ing structure for water reactivity in addition to thehazards listed in the other triangles:

4—Not used with the slashed W and a re-activity ranking of 4

3—Can react explosively with water2—May react with water or form

explosive mixtures with water1—May react vigorously with water0—Slashed W is not used with a reactiv-

ity ranking of 0

Figure 25-25 Primary and subsidiary placards.


HEALTHFLAMMABILITYREACTIVITYPROTECTIVEEQUIPMENT

Consult MSDS for further hazard information and instructions.

Figure 25-27 HMIS label.

Safety For high-security shipments the driveris armed as are the personnel in the escortvehicle. If an incident occurs involving one ofthese vehicles, firefighters must obey the com-mands of the escorting personnel and deter-mine if they have made the appropriatenotifications.

Some potential problems exist with the NFPA 704system, because it groups all of the chemical haz-ards listed in a building into one sign. If the sign isplaced on a tank that contains one material, the sys-tem does a good job of warning about the contentsof the tank, but does not provide the name of theproduct. For a facility that has hundreds—if notthousands—of materials, the system will only warnof the worst-case scenario. As an example, dramati-cally different tactics are used to handle a flamma-ble gas incident versus a flammable liquids incident,but both can be classified as fire hazard 4. The sys-tem is best used to alert the first responder to thepresence of hazardous materials and to warn of theworst-case scenario.

Hazardous MaterialsInformation SystemCommonly referred to as HMIS, the HazardousMaterials Information System was designed toprovide a mechanism to comply with the federalhazard communication regulation, which requiresthat all containers be marked with the appropriatehazard warnings and the ingredients be providedon the label, Figure 25-27. Many products thatcome into the workplace are missing adequatewarning labels. The HMIS is not a uniform sys-tem. It can be developed by the facility or by themanufacturer of the labels, so one system mayvary from another. Most systems are similar to theNFPA 704 system and use blue, red, and yellowcolors with a numbering system that provides anindication of hazard. The colors may be used in atriangle format or, in most cases, as stacked bars.The numbers are usually 0–4, the same as theNFPA system, but in rare cases may differ from

the NFPA system. The facility manager or otherrepresentative should have the key to the symbols,or a chart should be provided somewhere in thefacility indicating what the symbols and the warn-ing levels are. The chart is usually stored with theMSDS. In most cases, a central location should bechosen for the MSDS and other hazard communi-cation information.

In some systems, a picture is provided of thelevel of PPE required for the substance. EachHMIS is different, and responders should notassume any particular hazard level until the warn-ing levels can be determined.

Military Warning SystemThe military uses the DOT placarding system whenpossible, but in some cases may use its own sys-tem. Within the DOT’s Emergency ResponseGuidebook, an emergency contact number is givenwhen responding to an incident involving a militaryshipment.

In most cases, for extremely hazardous materi-als, arms, explosives, or secret shipments, firefight-ers can assume prior to their arrival that themilitary is already aware of the incident and proba-bly already responding. The higher the hazard themore likely there will be an escort for the ship-ment. There may be shipments in which the driverof the truck is not allowed to leave the cab of thetruck and may provide warnings to stay away fromthe truck.

If the driver and escort crew are killed or seriouslyinjured in the accident, it would be advisable tonotify the military about the incident, although withsatellite tracking help is probably already on theway. The phone number to contact the military is inthe DOT ERG, along with Chemtrec’s and otheremergency contact numbers.

Other incidents involving fuels, food, or militaryequipment may require notification of the military.

The military typically uses its own marking sys-tem at its facilities to mark the buildings. The mili-tary uses a series of symbols and a numericalranking system as shown in Figure 25-28.

770 ■ CHAPTER 25

Figure 25-29 The owner of a pipeline is required toprovide the contents of the pipe, the owner’s name,and an emergency contact number.

Chemical HazardSymbol

MassDetonation

Explosive withFragment Hazard

ModerateFire Hazard

MassFire Hazard

Wear ProtectiveMask or Breathing

Apparatus

Apply No Water

21

3 4

Figure 25-28 Military placards.

Pipeline MarkingsAny place an underground pipeline crosses a mode oftransportation the pipeline owner is required to placea sign like the one shown in Figure 25-29 that indi-cates the pipeline contents, owner, and emergencycontact number. The pipeline contents may be gen-

eral, as in “petroleum products,” because the samepipeline may be used to ship fuel oil, gasoline, motoroil, or other products. Dedicated pipelines that carryonly one product will be marked with the specificproduct that it carries. The pipeline should be buried aminimum of 3 feet and should be adequately marked.

Many of the larger pipelines, such as the Colonialpipeline that originates in Texas and ends in NewYork, are 26 inches in diameter along the mainpipeline. In the event of a release involving thepipeline, the line will be shut down immediately.Even with this immediate shutdown, the potentialexists to lose several hundred thousand gallons ofhazardous materials because the distance betweenthe shutoffs is substantial.

An incident involving a pipeline can be a seriousevent—firefighters should not underestimate theneed for considerable local, state, and federalresources. Within the fire department alone, consid-erable resources may be required such as commandstaff, logistic support, communications, and tacticalunits. A fuel oil pipeline rupture in Reston, Virginia,resulted in the loss of more than 400,000 gallons offuel, requiring considerable resources from severalstates to control the spill. The resources includedemergency response organizations; local, state, andfederal assistance; and a considerable number of pri-vate cleanup companies.


Note Some pipelines move one type of prod-uct, while others move several different typeseach day.

Figure 25-31 “Pesticide” placards.

Figure 25-30 The label describes the contents ofthe drum.

The product in the pipelines varies from liquefiedgases and petroleum products to slurried material.Pipeline companies are required to conduct in-service training and tours for the emergency respon-ders in the communities their pipelines transverse.When firefighters have an incident on or near anypipeline, it is advisable to notify the pipeline ownerof the incident, even if they are pretty sure thepipeline was not damaged. A train derailment in Cal-ifornia caused a pipeline to shift, and the pipeline didnot release any product until several days after theoriginal derailment occurred. Most pipeline opera-tors would like to have the opportunity to check theline as opposed to having a catastrophic release sev-eral days later because the line was not checked.

Container MarkingsMost containers such as drums are marked with thecontents of the drum, Figure 25-30, while cylindershave the name of the product stenciled on the side ofthe cylinder. In bulk shipments the bulk container willhave the name of the product stenciled on the side.

Trucks that are dedicated haulers will also stencil ormark the product name on two sides of the vehicle.

Pesticide Container MarkingsDue to their toxicity, pesticides are regulated by theEPA as to how they are to be marked. The label on apesticide container, such as the one shown inFigure 25-31, will have the manufacturer’s name forthe pesticide, which is not usually the chemical namefor the product. The label will also contain a signalword such as “Danger,” “Warning,” or “Caution.”

In the United States the EPA issues an EPA regis-tration number and in Canada the label will have apest control number. The label will also include a pre-cautionary statement and a hazard statement, exam-ples of which include “Keep from Waterways,” and“Keep Away from Children.” The active ingredientswill be listed by name and percentage; in most casesthe active ingredients are usually a small percentageof the product. Inert ingredients are also listed but notspecifically named. For liquid pesticides the “inert”ingredient is usually kerosene or diesel fuel, an itemnot normally considered “inert,” except by the EPA.

CONTAINERSHazardous materials come in a variety of containersof many shapes and sizes, from 1-ounce bottles andlarger bags to tanks and ships carrying hundreds ofthousands of gallons. A survey of the materials in theaverage home will reveal a wide variety of storagecontainers. Compressed gas cylinders hold propane;steel containers hold flammable and combustible liq-uids; bottles, jars, and small drums hold variousproducts. Plastic-lined cardboard boxes, and bags ofvarious types are also used for chemical storage.

772 ■ CHAPTER 25

Figure 25-32 The type of container can providesome clues as to the contents of the container.Because this drum is reinforced, it has a high likeli-hood of containing an extremely hazardous material.

The type of material and the end use for the prod-uct determine the packaging. Packaging used tostore household or consumer commodities is usuallydifferent than the industrial version. In some casesthe industrial version may be full-strength undilutedproduct, whereas the household version is only asmall percentage of that strength mixed with a lesshazardous substance such as water. The type of con-tainer usually provides a good clue as to the con-tents of the package.

When looking at the recognition and identifica-tion process, first responders should be alert foranything unusual when arriving at an incident.When on an EMS call to a residential home, itwould be unusual to find a 55-gallon drum in a bed-room along with glassware associated with a labenvironment. These types of recognition and identi-fication clues should alert the first responders thatadditional assistance may be required. Arriving atan auto repair garage and finding 55-gallon drumsand compressed gas cylinders should not be unex-pected, however.

GeneralContainers come in a variety of sizes and shapesand the general category of containers is not excep-tional. Most of the general containers are designedfor household use but will be carried in large quan-tities when moved in transportation. When movingto bags and into drums and cylinders the move ismade from household to industrial use. All of thesetypes can be used in the home, but a super sackwhich can hold thousands of pounds of materials isnot usually considered household.

Cardboard BoxesWith the popularity of shopping clubs and discountwarehouses, more and more homeowners are buy-ing materials by the case, when in the past theybought in much smaller quantities. Cardboard boxesare used to ship and contain hazardous materials.They can hold glass, metal, or plastic bottles. Insome cases they may have a plastic lining, such asthe box shown in Figure 25-33, which holds sulfu-ric acid. Many household pesticides, insecticides,and fertilizers are contained in cardboard boxes.With the exception of these products and sulfuricacid, most products contained in boxes are usuallynot extremely toxic to humans, but may present anenvironmental threat. Materials in transport to sup-pliers may be transported in larger cardboard boxesand then broken down at the retail level. Respon-ders should note any labels on these packages, butthe absence of any labels does not indicate that haz-ardous materials are not present.

BottlesFrom 1-ounce bottles to 1-gallon bottles, the varietyof containers is endless and the types of productscontained in them too numerous to mention. Inrecent times manufacturers have begun to take pre-cautions when packaging their materials for trans-port and use, especially when glass bottles are used.Nowadays, when chemicals are shipped in glass

Streetsmart Tip The more substantial,durable, and fortified a container is, like thecontainer shown in Figure 25-32, the morelikely the material inside is dangerous.

On the other hand, materials transported in fiber-board drums usually have no significance withregard to human health, although they may pose arisk to the environment.


Figure 25-33 Typically, chemicals that can causeharm are not packaged in cardboard. This sulfuricacid is one example of a material that can causeharm, but unfortunately is packaged in cardboard.

Figure 25-34 To protect the glass bottle, which hasa corrosive in it, a carboy is used in case the bottle isdropped.

Figure 25-35 This glass jar is coated with a plasticcoating that will not allow the liquid to spill out if theglass is broken or dropped.

protect against potential damage during transporta-tion. If the container is dropped, the bottle shouldsurvive the fall. Carboys are usually seen in labora-tories and in smaller chemical production facilities.

Ensuring the material’s compatibility with thecontainer it will be stored in is important, but theone area that usually results in a release is the use ofan improper cap. The chemical must not only becompatible with the glass, it must also be compati-ble with the material the lid is composed of. A vari-ety of materials are used in the manufacturing oflids. Many new glass containers, like the one shownin Figure 25-35, are coated with plastic to avoid thebottle being broken when dropped. Even if the bot-tle is cracked, the contents are supposed to remainsealed within the plastic coating.

BagsBags are also commonly used as containers forchemicals. Bags can be as simple as paper bags orplastic-lined paper bags to fiber bags, plastic bags,and the reinforced super sacks or tote bags. It mightbe a surprise to open the back of a trailer and findfour super sacks like those shown in Figure 25-36carrying a material that is classified as a poison. Bags

bottles, the bottles are usually packed in cardboardboxes and insulated from potential damage. One-gallon glass containers are usually shipped in whatis known as carboys, like the one shown inFigure 25-34. Carboys provide a protective cover to

774 ■ CHAPTER 25

Caution Other than the hazard of the chemi-cal itself, the big hazard of all cylinders is thatthey are pressurized.

TABLE 25-7

Figure 25-36 It can be quite surprising to open theback of a tractor trailer and find these super sacks.They can hold solid materials, some of which can betoxic.

carry anything from food items to poisonous pesti-cides, and the method of transportation varies widely.

DrumsWhen discussing hazardous materials, drums are thecontainers with which most responders are familiar.They vary from 1-gallon sizes up to a 95-gallon over-pack drum. The construction varies from fiberboardto stainless steel. The typical drum holds 55 gallonsand weighs 400 to 1,000 pounds. It is possible to getan idea of what a drum may contain by the construc-tion of the drum. Table 25-7 provides an indication

of potential drum contents, but this is not an absolutelisting; contents can and do vary from drum to drum.

CylindersCylinders, like those shown in Figure 25-37, comein 1-pound sizes up to several thousand pounds andcarry a variety of chemical products. The productand its chemical and physical properties will deter-mine in what type of container the product is stored.

The pressures range from a low of 200 psi to a highof 5,000 psi. One of the most common cylindersfirefighters run across is the propane tank, whichrange from 1 pound up to millions of gallons. Inresidential homes, firefighters will find everythingfrom the 20-gallon cylinder for barbecues to the100- to 250-pound cylinders used as a fuel sourcefor the home. In some areas it is not uncommon tofind 1,000-pound cylinders and often they areburied underground.

Specialized cylinders that hold cryogenic gases(extremely cold) appear to be high pressure, but inreality are low pressure. The bulkiness of the cylin-ders is a result of the large amount of insulationrequired to keep the material cold. Cylinders usuallyhave relief valves or frangible disks in the eventthey are overpressurized or are involved in a fire.Most communities, regardless of their size, have

Drum ContentsTYPE OF DRUM POSSIBLE CONTENTS (IN ORDER OF LIKELIHOOD)

Fiberboard Dry, granular material such as floor sweep, sawdust, fertilizers, plastic(cardboard), unlined pellets, grain, etc.

Fiberboard, plastic Wetted material, slurries, foodstuffs, material that may affect lined cardboard or could permeate the cardboard

Plastic (poly) Corrosives such as hydrochloric acid and sodium hydroxide, some combustibles, foodstuffs such as pig intestines

Steel Flammable materials such as methyl alcohol, combustible materials such as fuel oil, motor oil, mild corrosives, and liquid materials used in food production

Stainless steel More hazardous corrosives such as oleum (concentrated sulfuric acid)

Aluminum Pesticides or materials that react with steel and cannot be shipped in a poly drum


Figure 25-37 Cylinders present additional risks toresponders because not only can the contents be haz-ardous, but if the cylinder is involved in a fire it mayexplode.

Note The area affected by a 100-pound chlo-rine cylinder release can be several miles,Figure 25-38, causing serious injuries if not fataleffects.

cylinders of chlorine and sulfur dioxide used inwater treatment. These cylinders come in 100- to150-pound and 1-ton cylinders, which could create amajor incident if they were ruptured or suffered arelease.

Totes and Bulk TanksBoth totes and bulk tanks are becoming more com-mon, sized as they are between drums and tanktrucks, and are used for a variety of purposes. Usedin industrial and food applications, they hold flam-mable, combustible, toxic, and corrosive materials.They are constructed of steel, aluminum, stainlesssteel, lined materials, poly tanks, and other prod-ucts, Figure 25-39. They can carry up to 500 gal-lons, but the usual capacity is 300 gallons. They aretransported on flatbed tractor trailers or in box-typetractor trailers.

A common incident with totes can occur duringoffloading. Tanks are offloaded from the bottomthrough a swinging valve, such as the one shown inFigure 25-40. It is a common occurrence for thisvalve to swing out during transport and get knockedoff during movement.

One unusual tote is made to transport calcium car-bide, a material that when it gets wet forms acety-lene gas, which is reactive and very flammable.

Miami Blvd.

Main St.

Sou

th D

river Ave.

Elm St.

Wind

School

Incident

Figure 25-38 The type of vapor cloud commonly referred to as a plumevaries with the terrain and buildings in the vicinity. The plume here repre-sents one of the most common types.

776 ■ CHAPTER 25

Figure 25-40 The most common type of spill occurswhen a valve is knocked off, releasing the contents.

Caution When dealing with tractor trailers therule is to expect the unexpected.

Note The types of containers that are shippedin these trailers vary from bags, boxes, anddrums to bulk tanks and cylinders.

having a majority. Pipelines can originate from anybulk storage facility and can cross many states, andsome type of pipeline system is found in every state.Because the amount in the pipelines varies it is impor-tant that first responders know the location of thepipelines and emergency contact names and phonenumbers so if there is a suspected problem they cannotify the pipeline owner immediately.

Highway TransportationContainersThe type of vehicle provides some important cluesas to the possible contents of the vehicle. The mostcommon truck is a tractor trailer or a box truck.There are four basic tank truck types that carry haz-ardous materials, with some additional specializedcontainers. Tractor trailers carry the whole varietyof hazardous materials and portable containers.They can carry loose material that is not containedin any fashion other than by the truck itself. Theycan carry portable tanks that hold 500 gallons orbulk bags that weigh several tons.

PipelinesPipelines vary in size and pressure, but can be sizedbetween 1/2 inch and more than 6 feet. They are com-monly buried underground. The most common prod-ucts they carry are natural gas, propane, and assortedliquid petroleum products. The larger petroleumpipelines originate in Texas and Louisiana and thenproceed up throughout the East Coast. The WestCoast also has its share of large pipelines, with Alaska

Nothing is routine. Until the driver has been inter-viewed, the shipping papers looked at, and the cargoactually examined, a firefighter cannot confirm ordeny the presence of hazardous materials. Some-times the signage on the trailer is an indication ofthe possible contents, and a trailer that has severalplacard holders is a likely candidate for hazardousmaterials transport. If a tractor trailer is refrigeratedlike the one shown in Figure 25-41 and is carryinghazardous materials, extra precautions must betaken because the materials may require the coldtemperature to remain stable.

Leakage is often found in containers known asintermodal containers or, more commonly, seacontainers. These types of containers are typicallyused on ships, then offloaded onto a tractor trailer orloaded directly onto a flatbed railcar. These contain-ers come from all over the world and can containany imaginable commodity.

Figure 25-39 The use of 55-gallon drums isdecreasing and the use of these portable bulk tanks isincreasing. Like the super sacks these can be hiddenaway in the back of a trailer.

Although the driver is supposed to have the ship-ping papers for the contents, on occasion the paper-work is missing or is sealed in the back of the


Figure 25-41 Although in most cases refrigeratedtrailers are carrying food, there exists the possibilitythat they may have chemicals that require refrigera-tion to remain stable.

trailer. Determining the contents of a trailer can bevery difficult and frustrating.

Tank trucks carry several hundred gallons up to amaximum of 10,000 gallons. The DOT allows max-imum loads by weight not by gallons, so the actualcapacity varies state to state. The most commontank truck is the gasoline tank truck, which usuallycarries 5,000 to 10,000 gallons. In September 1995the DOT changed the regulations covering tanktrucks, so two systems are used for identifying tanktrucks, Figure 25-42. In the past the DOT wrotespecifications as to how the manufacturer shouldbuild a tank truck. Today, they have established performance-based standards for the construction.The DOT allows trucks that were manufacturedbefore the new regulation to remain on the road, aslong as they meet the applicable inspection require-ments. The four basic types of tank trucks are:

DOT-406/MC-306 gasoline tank truckDOT-407/MC-307 chemical haulerDOT-412/MC-312 corrosive tankerMC-331 pressurized tanker

Figure 25-43 In most cases the shipping papers willbe with the driver in the cab of the truck, but theymay be in a special tube located on the trailer.

The DOT numbers are the more recently manufac-tured tanks, and the MC (motor carrier) numbersidentify those tanks manufactured prior to Septem-ber 1995. There are some differences in construc-tion of the two types—some of which favor theemergency responders, others favor the shippingcompany—but overall the newer tanks hold up bet-ter during accidents and rollovers. If unsure of thetype of tank, all tank trucks have specification(spec) plates, which list all the pertinent informa-tion regarding that tank. The spec plate in manycases is located on the passenger side of the tanknear the front of the tank. In some cases, shippingpapers or MSDS are located in a paper holder asshown in Figure 25-43 (tube).

Figure 25-42 Many of the differences between a 306and a 406 tank truck are internal. The biggest differenceis that the dome covers on a 406 are less likely to openduring a rollover, although the skin of the tank is thin-ner. (Photo courtesy of Maryland Department of the Environment)

778 ■ CHAPTER 25

Figure 25-45 Most 406/306 trucks have more thanone tank (pots) and the number of tanks is indicatedby the number of valves or the number of dome cov-ers on top of the truck. (Photo courtesy of Maryland Depart-ment of the Environment)

Caution During a rollover, the bulkheads mayshift, allowing all products to mix.

DOT-406/MC-306This is the most common tank truck on the roadtoday, Figure 25-44, and for that reason, along withthe large number of shipments, suffers the mostaccidents. Although the most common products car-ried on these trucks are gasoline and diesel fuel,almost any flammable or combustible liquid can befound on these types of trucks. This truck is knownfor its elliptical shape and is usually made of alu-minum. Older style tanks used to be made of steel,which presented an explosive situation known as aBLEVE. The tanks generally have three or four sep-arate compartments, but two to five compartmentsare not uncommon. Newer style tanks have consid-erable vapor recovery systems as well as rolloverprotection, and in some cases these features arecombined. The valving and piping are contained onthe bottom of the tank, as shown in Figure 25-45,

and the number of pots is indicated by the numberof outlets as well as the number of manhole assem-blies located on top of the tank. The maximum pres-sure that this truck can hold is 3 psi. Thecompartments are separated by bulkheads, whichusually fail during a rollover situation. Although inmost states the shipper is not allowed to ship amixed load of flammable and combustible materi-als, widely differing loads can be encountered fromcompartment to compartment.

Figure 25-44 The DOT-406/MC-306 is the most common truck on the highway today and is referred to as agasoline tanker. It can and frequently does carry other types of flammable and combustible liquids. (Photo courtesy ofMaryland Department of the Environment)

On initial examination it may appear that only onetank has ruptured and is leaking, but it is possibleto lose the entire contents of the tank through aleak in one compartment, like that shown in Fig-ure 25-46. In the majority of rollovers experiencehas shown that at least one bulkhead has separatedin almost every accident, resulting in product mix-ing. In most cases this is not a big problembecause it may only be the mixing of differentgrades of gasoline. Within the individual tanksthemselves, baffles limit the movement of theproduct within the tank. The emergency shutoffvalves, Figure 25-47, are located on the driver’sside near the front of the tank and near the pipingon the passenger side.

DOT-407/MC-307The DOT-407/MC-307 tankers are the workhorsesof the chemical industry, Figure 25-48. They carrya variety of materials including flammable, com-bustible, corrosive, poisonous, and food products.


Figure 25-47 On most trucks there is a minimum ofone emergency shutoff, and with most there are two.The most common location is near the driver’s door;the other is usually located near the valve area.

Baffle

Tank shell

Bulkhead

Separation

Baffle holes

Figure 25-46 When a truck rolls over on its side, the internal baf-fles and bulkheads may shift. The internal baffles reduce the amountof sloshing the liquid will do when the truck starts and stops. Thebaffles will allow product to move through the holes in the bafflewall. A bulkhead separates the compartments and does not allowthe products to mix. Shown in the photograph is an MC-306 thatrolled on its side. The side wall of the tank has been cut away,revealing a baffle and a bulkhead. Also shown is the separation thattook place between the tank shell and the baffles/bulkhead. Whenthe tank wall was cut away, strips of the tank shell were left wherethey should have connected to a baffle or bulkhead.

Figure 25-48 On the right is an insulated MC-307/DOT-407, and on the left is an uninsulated MC-307/DOT-407. Both trucks hold comparable products,but the insulated one holds products that are heatedor may require heating to offload.

The two basic types of chemical tanks are insulatedand uninsulated. The insulated tank can have anumber of additional concerns that do not apply toan uninsulated tank. These tanks usually hold 2,000to 7,000 gallons, lower amounts than the 406/306because most of the products they carry are heavierthan petroleum products. The average amount foundin these tanks is 5,000 gallons.

The uninsulated tank is round and has stiffeningrings around the tank. The offloading piping islocated on the bottom or off the rear of the tank.These tanks are composed of only one compart-ment, and its loading piping and manhole are usu-ally on the top in the middle. These tanksgenerally do not hold up as well during rollovers

780 ■ CHAPTER 25

and accidents as the insulated version. The shell ismade of stainless steel and can hold pressures upto 40 psi.

The insulated tank, Figure 25-49, is a coveredversion of the uninsulated tank, although in somecases it has a slightly smaller inner tank. Theinner tank is made of stainless steel with about6 inches of insulation, and the outer shell is madeof aluminum. The inner tank may also be linedwith a fiberglass or other liner depending on thechemical that is carried. Due to the aluminum andinsulation these tanks hold up remarkably wellduring rollovers.

Figure 25-49 This insulated version is identical to the uninsulated tank but has an aluminum cover and insula-tion. Note the differences in these two trucks. The one on the right has safety railings around the manhole.Although not an absolute rule, the truck on the right would carry more dangerous products and would have otheradded safety features. Most of these items are not required but were added by the trucking company.

Figure 25-50 Products carried in an insulated407/307 need to remain either heated or cooled.Some products may need to be heated for offloading.The heater coils that run around the tank heat theproduct up, allowing it to be offloaded.

Safety One of the major problems with thisinsulated tank is that in the event of a leak, thelocation where the material leaks out of theouter shell is usually nowhere near the leak onthe inner shell.

Within the insulation there can be heating andcooling lines depending on the product being car-ried, Figure 25-50. Products such as paint areshipped at 170°F and need to be heated to that tem-perature for offloading. Some products need toremain at certain temperatures to remain stable, andfirst responders need to be aware of any specialrequirements.

In general, both types of tanks have rollover pro-tection, similar piping, and relief valves that servetwo purposes: overpressurization and vacuum pro-tection. The emergency shutoffs are located near thefront of the tank on the driver’s side and near theoffloading piping.

DOT-412/MC-312These tankers, Figure 25-51, carry a wide varietyof corrosives, both acids and bases. These tankersare round and are smaller than the 306s and 307sdue to the weight of the corrosives they carry. Mostpetroleum products weigh about 8 pounds per gal-lon while some corrosives weigh up to 15 poundsper gallon. Because of the weight, the stiffeningrings used are generally bulkier than the ones usedon DOT-407 tanks. These tankers are constructedof a single tank that carries up to 7,000 gallons,with most tanks holding 5,000 or fewer gallons.The tanks are made of stainless steel and are usu-ally lined to protect against corrosion. The pipingcan be on top of the tank located in the middle, but


Figure 25-51 The DOT-412/MC-312 is designed tocarry corrosives and is similar in design to the uninsu-lated 307, although smaller. The inner tank may belined with a variety of materials to prevent the corro-sive from attacking the tank.

Figure 25-52 The black coating around the man-hole indicates that a corrosive is being carried. It isused to protect the tank from spillage. It is notrequired nor will it be found on all corrosive tanks.

Figure 25-53 MC-331 tanks carry liquefied com-pressed gases such as propane and ammonia. Theyare made of steel and are designed to carry a varietyof products.

is usually located on the end of the tanker. The pip-ing is usually contained within a housing thatincludes the manhole and offload piping. Thishousing protects the piping in the event of arollover, Figure 25-52. The area around the man-hole is usually coated with a material that resiststhe chemical being carried and is usually a black,tar-like coating.

MC-331MC-331 tanks look like bullets and are noted fortheir rounded ends and smooth exterior, as shown inFigure 25-53. They carry liquefied gases that areliquefied by pressure. One of the most commonproducts carried in this type of tank is propane.They also carry ammonia, butane, and other flam-mable and corrosive gases. These tanks carry up to11,500 gallons and have a general pressure of 200psi, although it can be as high as 500 psi. The reliefvalves are located on top of the tank at the rear ofthe trailer, and they sometimes malfunction during arollover. The tanks are made of steel, are uninsu-lated, and are heavily fortified with heavy boltsused in the piping and manholes. The tanks are usu-ally painted white or silver to reduce the potentialheating by sunlight.

The tanks contain a liquid along with a certainamount of vapor. The most liquid the tank is sup-posed to have is 80 percent to allow for expansionwhen heated. The liquid in the tanks is at atmo-spheric temperature but on release can go below0°F (propane is �90°F) and could cause frostbiteupon contact. The pressure in these tanks is ofconcern when responding to incidents involvingthese tanks.

782 ■ CHAPTER 25

Boiling Liquid Expanding VaporExplosion (BLEVE)

Liquid Level

Vapor Space Relief Valve Fire impinging on a propane tank.

As heat increases inside of tank, thepressure also increases. The liquid willbegin to boil.

LowerLevel

As the pressure increases, the reliefvalve will open, releasing propane.The propane, being heavier than air,will sink.

The vapor will reach the fire and ignite.

The relief valve will ignite, also causingheat to be on the tank by that flame.The pressure will increase in the tank.

As the pressure in the tank is increasing,the tank may discolor and the pitch ofthe relief valve will get higher. Eventually the tank will rupture. This is known as a BLEVE.

Figure 25-54 Diagram of a BLEVE.

Firefighter Fact Temperatures and Pressur-ized Container When a propane tank is emp-tied and, hence, the pressure reduced, thetemperature of the propane drops below 0°F.Temperature, pressure, and volume are interre-lated. Think of an SCBA bottle. When it getsfilled it becomes hot because the pressure andvolume are increasing. When the SCBA bottle isused, it becomes cold because it is losing pres-sure and volume. Any time one of the parame-ters is changed, there is a corresponding changein the other properties. When a pressurized gasis pressurized to a point that it becomes a liquid,as is the case with propane, it allows for a lot ofpropane to be stored in a small container. Whenreleased, however, the temperature will dropbecause the pressure is decreasing in the con-tainer. This is known as autorefrigeration.

Safety If the pressure increases at a ratehigher than the relief valve can handle, the tankwill explode. These explosions have beenknown to send pieces of the tank up to a mile,with the ends of the tank typically traveling thefarthest, although any part is subject to becomea projectile.

When tanks, trucks, tank cars, or other containers areinvolved in a fire situation there are a number of haz-ards. One very deadly hazard is known as a boilingliquid expanding vapor explosion (BLEVE), Fig-ure 25-54. A large number of firefighters have beenkilled by propane tank BLEVEs, and when a BLEVE


occurs it usually results in more than one firefighterbeing killed at a single incident. The type of containerand the product within the container will dictate howsevere a BLEVE may be. The basis of a BLEVE isthe fact that the pressure inside the container increasesand cannot be held by the container. The contents areviolently released, and if the material is flammable, anexplosion or large fireball occurs. In the recent pastthere have been several incidents involving BLEVEsthat resulted in emergency responder deaths andinjuries, thus emphasizing the need to recognize andprevent this event before it occurs.

Another phenomenon that transpires with contain-ers is known as violent tank rupture (VTR), whichoccurs with nonflammable materials. The concept isthe same as a BLEVE, but there is not a characteris-tic fireball and explosion. With both a BLEVE and aVTR there is some form of heat increase inside thecontainer, typically from a nearby fire. The fire heatsthe container, which heats the contents. The contentswill boil, which creates expanding vapors, which inturn increase the pressure inside the container. Insome containers the relief valve will activate, reliev-ing the pressure. In some cases the pressure insidethe tank is greater than the relief valve can handleand the pressure continues to increase. One of twopossibilities can occur with a BLEVE or a VTR.One possibility is that the relief valve will not beable to handle the increase in pressure and the tankwill fail. The other possibility is that the fire or heatsource that is creating the problem will weaken thecontainer shell, and the resulting increasing pressurewill vent at this weakened portion of the container. Ifthe heat source is a fire and the container product isflammable, when the relief valve activates the rawproduct coming out of the container typicallyignites. This may increase the temperature of thetank, increasing the pressure. It is never advisable toextinguish the fire coming from a relief valve, as thatis a safety mechanism. It is possible to cool the topof the tank near the relief valve with an unstaffedhose stream. The difference between a BLEVE and aVTR occurs when the container fails. A BLEVEoccurs with flammable liquids, such as propane.When the container fails, the vapors of the flamma-ble liquid ignite, creating the explosion. How thecontainer ruptures and the amount of productreleased will determine how severe the explosionwill be. With a VTR the container will fail. Since theproduct is nonflammable, the product will not ignite.The only event is a rupture of the container, spillingits contents. The container can still rocket, and theresulting release of pressure can be violent. A VTRcan occur with a container of water or other “non-hazardous” material. As an example a 55-gallonsteel drum of water, when heated, can travel several

hundred feet depending on where the release point ison the container. In most cases the bungs (screw-topcaps) will release, flying a considerable distance,and the container will remain mostly intact.

The failure of the container when impinged froma fire usually occurs as the fire is impacting the tankin the vapor space. When heat is applied to a sectionof the tank that has no internal mechanism to pro-vide cooling, failure of the steel can occur. Whenfire impinges on the liquid portion of the tank, theliquid will distribute the heat spread internally andthe steel tank typically will not weaken. The prob-lem is that responding firefighters do not usuallyknow the liquid level, and one cannot easily predictwhen a tank may fail. Any fire impingement on atank is a serious problem, and withdrawing from thescene may be the best course of action. This bringsup another interesting note: A casual observation ofBLEVEs indicates that most BLEVEs and firefighterdeaths occur within the first few minutes of arrival.The clock starts ticking on the BLEVE time bombfrom the first minute heat is applied to the tank. Theclock does not start with the 9-1-1 call or the arrivalof firefighters. The critical time for safety may havealready passed before firefighters arrive on thescene. If firefighters arrive at an incident involving apropane tank on fire or being impinged by fire, theyare in extreme danger. If the relief valve is not oper-ating, the danger is even more pronounced. Operat-ing in close proximity to a tank in this situation canbe a fatal mistake. Firefighters should follow thisrisk/benefit analysis: Risk a lot to save a lot, and riska little to save a little.

One recent event involved the death of two fire-fighters and injuries to seven other emergencyresponders. The location was a farm, at which apropane tank was on fire. The relief valve on thetank was operating and the vapors from the reliefvalve were on fire. About eight minutes after thefirefighters had arrived, the tank exploded into fourseparate parts. The four parts went in four differentdirections. The two firefighters who died were 105feet away and were struck by one piece of the tank,dying instantly.

In two other farm incidents, firefighters lost theirlives. In 1993 a fire and BLEVE in Ste. Elisabeth deWarwick, Quebec, Canada, killed three firefighters.In 1997 in Burnside, Illinois, two firefighters losttheir lives in a fire and BLEVE. In all three of thesefatal BLEVE events, the relief valves were operat-ing upon arrival of the fire department.

One other event worth noting is the 1984PEMEX LPG Terminal fire in Mexico City, Mex-ico. An 8-inch pipeline broke while filling a tank atthe terminal. The resulting vapor cloud, which was650 feet by 572 feet by 8 feet, ignited. This resulted

784 ■ CHAPTER 25

in an explosion, which included a ground shock,and a major fire. The terminal had two largespheres, four small spheres, and forty-eight horizon-tal tanks. About fifteen minutes into the fire the firstBLEVE occurred, and for the next ninety minutestanks continued to BLEVE. Tanks and liquidpropane rained down on the adjacent community.The death toll exceeded 500 people, and thousandswere injured.

In 1983 five Buffalo, New York, firefighters losttheir lives when a three-story building collapsed.Nine other firefighters were injured in the massiveexplosion. The force of the explosion caused thefirst arriving apparatus, including a ladder truck, tobe blown across the street. A propane tank inside thebuilding had been struck and was leaking. Anunknown ignition source sparked the explosionminutes after fire crews arrived.

In January 2003 a propane truck (MC-331) wentover a guardrail and fell to the ground 35 feetbelow. The tank ruptured and the leaking propaneignited, resulting in a 600-foot-high fireball. Theresulting explosion moved the truck several hundredfeet away from the first impact area. The driver ofthe truck was killed in the accident.

As can be noted in the stories above, BLEVEsand VTRs can result in injuries and fatalities. Anytime containers are under stress, such as during afire, they can fail. Many times they fail violentlyand with severe consequences. Some containershave relief valves, while others do not. Materialsthat are highly poisonous such as chlorine will nothave a relief valve; they will have a fusible metalplug that vents the pressure of the tank. This fusiblemetal plug is not like a relief valve that shuts offwhen the pressure inside the tank is decreased.Once a fusible metal plug melts, the contents of thetank come out, no matter the pressure. When a tankis on fire or is being impinged by fire, the tank isbeing weakened and the contents are being heated,creating increased pressure. Some of the generalrules of firefighting and propane tanks (or othercontainers under pressure) are as follows:

Firefighters should withdraw immediately in thecase of rising sound from venting relief valves ordiscoloration of the tank.Fire must be fought from a distance withunstaffed hose holders or monitor nozzles.The tank should be cooled with flooding quanti-ties long after the fire is out. A minimum of500 gpm at the point of flame impingement isrecommended by the NFPA.

If the water is vaporizing on contact, firefight-ers are not putting enough water on the tank.Water should be running off the tank if it isbeing cooled.

Firefighters should not direct water at reliefvalves or safety devices, as icing may occur.Icing would block the venting material, whichcould cause an increase in pressure inside thetank.The tank may fail from any direction, but fire-fighters should avoid the ends of the tank.For massive fire, it is recommended to useunmanned hose holders or monitor nozzles. Ifthis is impossible, firefighters should withdrawfrom the area and let the fire burn.The dangers associated with a BLEVE are:

The fireball can engulf responders andexposures.Metal parts of the tank can fly considerabledistances.Liquid propane can be released into the sur-rounding area and be ignited.The shock wave, air blast, or flying metalparts created by a BLEVE can collapse build-ings or move responders and equipment.

Specialized Tank TrucksThese types of tank trucks are used to carry uniquechemicals or chemicals that have to be transported ina certain fashion. When gases are transported, theyare transported as liquefied gases, as was describedwith the MC-331 tank trucks. They can also betransported as refrigerated gases or as compressedgases as will be described in this section. Othertrucks are dry bulk which can carry a variety ofproducts from grain to explosives. Materials thatrequired high temperatures are transported in specialvehicles to keep them hot. The intermodal series oftanks are cousins to their full size highway tanks butcarry the chemicals in a comparable fashion.

MC-338 Cryogenic TankersMC-338 tankers are uniquely constructed like theone shown in Figure 25-55. They have a tank withan outer shell. The inner container is steel or nickel,with a substantial layer of insulation; the exterior isaluminum or mild steel. The space between theshells is placed under a vacuum to assist in the cool-ing process. The ends of the tank are flat, and thepiping is contained usually at the end of the tankerin a double door box. Relief valves are located ontop of the tank, to the rear of the tank. The best wayto describe this tanker is to compare it to a Thermosbottle on wheels. Cryogenic materials are gases thathave been refrigerated to a temperature that con-verts them to liquids. Unlike liquefied gases, whichuse pressure to reduce them to liquids, these arecooled to the point of becoming liquid. To remain


liquids, the material must be kept cool. To be acryogenic material the liquid has to be at least�150°F and can be as cold as �456°F.

The most common products are nitrogen, carbondioxide, oxygen (liquid oxygen or LOX), argon,and hydrogen. The material inside is kept liquid byvacuum, and when on the road the tank will have amaximum of 25 psi. As the truck travels the sunwill heat the material, and the pressure willincrease. As the pressure increases the relief valvewill open up, relieving any access pressure into theatmosphere.

When the truck makes a delivery, the pressureneeds to be increased to push the liquid out of thetank. The driver opens the piping and allows thematerial to flow into an evaporator which islocated just in front of the rear wheels of the tank.Once in the evaporator the material will heat up,increasing the pressure in the tank and forcing theliquid into the receiving tank. During transporta-tion and offloading, a large amount of ice willbuild up on the piping and valves.

Tube TrailersTube trailers, Figure 25-57, contain several pressur-ized vessels, constructed much like the MC-331tank. They are constructed of steel and have pres-sures ranging from 2,000 to 6,000 psi. They holdpressurized gases such as air, helium, and oxygen.The piping and controls are usually located on the

Figure 25-55 The MC-338 carries cynogenic liquefied gases. The tank resembles a rolling Thermos bottle.

Figure 25-56 When transporting liquids it is notuncommon to see vapors coming from the reliefvalves. The truck can only travel with the tank at25 psi or less. As it heats, the pressure increases, trig-gering the relief valve. This is a normal situation, andthe tank will vent until below the 25 psi. Whenoffloading the pressure can be increased to assist withthe offloading procedure.

Figure 25-57 The tubes on this trailer contain pres-surized gases. The pressure can vary from 2,000 to6,000 psi.

Note It is not uncommon to see a white vaporcloud like that shown in Figure 25-56 comingfrom the relief valves while the truck is travelingon the highway or sitting alongside the road.This is a normal occurrence and is not cause foralarm.

rear of the trailer, but could be in the front. The typ-ical delivery mode is that the driver will drop a fulltrailer off at a facility and pick up an empty one forrefilling. Although they are not subject to BLEVEsbecause they only contain a gas, if involved in afire, tube trailers can experience a VTR and rocketin the same fashion as a BLEVE.

Dry Bulk TanksDry bulk tanks resemble large uninsulated MC-307s in shape with bottom hoppers to unload theproduct, as shown in Figure 25-58. The tankshold dry products and sometimes a slurry, likeconcrete. The most common products are fertiliz-ers, lime, flour, grain, and other food products.The potential hazard when dealing with thesetankers is predominantly environmental but attimes these tankers contain toxic materials. They

786 ■ CHAPTER 25

are usually offloaded using air pressure eitherfrom the truck itself or at the facility.

Hot Materials TankerHot materials tankers vary in that they can be modi-fied MC-306s, 307s, or dry bulk containers,Figure 25-59. They may have a mechanism to keepthe material hot or it may be loaded hot. It mayrequire heating prior to offloading. Common productsare tar, asphalt, and molten sulfur, fuel oil #7 and #8.

Figure 25-59 These trucks carry molten products and can be heating the productwhile driving. This practice is illegal but is found on occasion. The fuels used to heatthe product are either diesel/kerosene or propane.

Safety The major problem with these tankersis the heated material itself. Anyone cominginto contact with the material could be seriouslyburned. The molten material could ignite thetruck or other combustibles.

Figure 25-58 Dry bulk tanks carry a variety of products. Some examples include fertiliz-ers, explosives, and concrete.


If the material is allowed to cool, it can causeproblems for the responders or the shipping com-pany. Tar trucks may be transported with a propaneor fuel oil flame ignited to heat the product en routeto the job site, although this is illegal in most states.

Intermodal TanksIntermodal tanks are increasing in use and carry thesame types of products as their highway and railcompanions, Table 25-8 and Figures 25-60, 25-61,

and 25-62 . They are called intermodal (IM)because they can be used on ships, railways, orhighways.

Note Smaller intermodal tanks may be foundinside of box-type tractor trailers.

Figure 25-60 This is an IMO-101 tank. Like thetotes, these are bulk tanks capable of carrying a largequantity of product. These are normally placed onships, then delivered locally by a truck, althoughtrains can also be used.

Figure 25-61 This is an intermodal tank, commonlyreferred to as an IM or IMO. This is a bulk tank thatcarries an average of 3,000 to 5,000 gallons. This tankis an IMO-101, which it is an atmospheric tank. Theorange panel indicates that it has a United Nations(UN) hazard code of 60 and a UN number of 2572.The code of 60 indicates that the product is a toxicmaterial. The UN number indicates that the product isphenylhydrazine. The name is also stenciled on thesides of the container, and there are toxic placards.

TABLE 25-8

IMO ContainersMAXIMUM

CONTAINER CAPACITY (GAL) PRESSURES (PSIG) PRODUCTS

IM-101 or IMO 6,340 25.4–100 Nonflammable liquids,Type 1 mild corrosives,

foods, and other products

IM-102 or 6,340 14.5–25.4 Flammable materials, IMO Type 2 corrosives, and other

industrial materials

Spec 51 or 6,418 100–500 Liquefied gases, muchIMO Type 5 like an MC-331

Specialized tanks Varies Varies Includes cryogenic tanksand tube banks (smalltube trailers) that carry thesame products as theirhighway counterparts

788 ■ CHAPTER 25

Intermodals follow three basic types: nonpressur-ized, pressurized, and highly pressurized. They arebuilt in two ways. In one, they sit inside a steelframe, called a box-type framework; in the other,the tank is part of the framework, called a beam-type intermodal. Like tank trucks they are assignedspecification numbers, IM-101, IM-102, Spec 51(specification 51). When used internationally theyare called IMOs. They are made to be dropped off ata facility and when empty picked up for refilling.

Rail TransportationAs with highway transportation there are only a fewtypes of railcars, and they are similar to their high-way counterparts. The piping and shape may be thesame but that is the extent of the similarities.

away from water supplies and easy access. Railincidents will involve multiple agencies, and thelocal community can expect a large contingent ofassistance coming from the state and federal gov-ernment, which in itself will be difficult to manage.

Railcars come in three basic types: nonpressurized,pressurized, and specialized cars. Although they arecategorized in this fashion, the commodities theycarry will determine the ultimate use of the car. Aswith highway transportation there are dedicated rail-cars that will be marked with the products they carry.

It carries chemicals, combustible and flammableliquids, corrosives, and slurries. The easiest way todetermine if the car is nonpressurized, such as theone shown in Figure 25-63, is to observe whetherthe valves, piping, and other appliances are locatedoutside of a protective housing. In some cases, thecar will be bottom unloaded, with the ability to loadthe car through the top, or the car may be top loadedand unloaded. The cars will usually have a smalldome cover, but the relief valves and other pipingare located outside of this dome. Most of the pipingis located on the catwalk on top of the car.

Some cars have unique paint schemes such asthose shown in Figure 25-64. Nonpressurized carscan be insulated and may have heating and coolinglines around the tank. Prior to offloading, the tankmay need to be heated to ease the offloadingprocess. Some nonpressurized railcars have anexpansion dome. The piping valves and fittings siton top of this dome, which was constructed to hold

Note In rail transportation the quantities aregreatly increased—up to 30,000 gallons for haz-ardous materials and up to 45,000 gallons fornonhazardous materials.

Figure 25-63 The indication that this is a nonpres-surized railcar is given by the fact that all of the valvesare on the outside of the tank and not containedwithin any protective housing.

Figure 25-62 This is another IMO-101, and thephoto shows that the orange panel indicates a hazardcode of 66 and a UN number of 2810. The hazardcode indicates that the product is a highly toxic mate-rial, and there are fifty-two different materials listedfor UN 2810. One would have to look at the shippingpapers to figure out what is being carried in this tank.The tank is marked “foodstuff only,” which means thatit is holding a product used in food. It is interesting tonote that many of the chemicals listed for UN 2810are chemical warfare agents such as sarin nerve agentand comparable materials. The most likely candidate,considering the “foodstuff only” label, would be amedical-type product

Caution The term nonpressurized car is actu-ally misapplied because it can have up to100 psi in the tank.

Rail incidents usually involve multiple railcars,whereas highway incidents usually involve one ortwo trucks. The incidents may occur in rural areas,


any potential expansion. These cars are not in regu-lar service but may be seen in larger industrial facil-ities that have their own railroad service on site.

Pressurized tank cars, Figure 25-65, also carry awide variety of products, including flammable gaseslike propane, and poisonous gases like chlorine andsulfur dioxide. The pressurized cars will have pres-sures in excess of 100 psi up to 600 psi. Most pres-sure cars that carry flammable materials will beinsulated with a spray-on insulation or may be ther-mally insulated. This insulation is 1 to 2 inchesthick and helps reduce the chance of a BLEVE dur-ing a fire situation. To determine if the railcar is apressurized car the firefighter can look at the specplate, which will have all of the valves, piping, andfittings located under the protective housing, on top

of the railcar. A catwalk around the protective hous-ing provides relatively easy access.

Specialized RailcarsSpecialized railcars have the same characteristics ashighway vehicles, and, in fact, in some cases high-way box trailers are loaded onto flatbed railcars.When transported in this fashion they are referred toas trailers on flat cars (TOFC). Regular box trailersas well as refrigerated trailers can be found on flatcars. Much like highway trailers, there are freightboxcars that haul the same products as their high-way trailers, with the exception of carrying muchlarger quantities. Examples of these cars are shownin Figure 25-66. The boxcars can carry boxes,cylinders, bulk tanks, totes, and super sacks. Refrig-erated railcars are similar to highway and inter-modal boxes and are referred to as reefers. Theycontain their own fuel source. Dry bulk closed rail-cars are common, and open hopper cars can also befound. Tube trailers for rail are also found, but theyare rarely used; the most common is a highway tubetrailer set on a flat car. Cryogenics are also carriedin railcars and have the same low pressure (25 psi)as in highway transportation, with the characteristicventing when the pressure increases.

Markings on RailcarsRailroads use the same placarding system used onhighways, with the exceptions noted in the placardsection. Railcars, however, are usually marked betterthan their counterparts on the highway; at the veryleast, the information is printed larger. In addition to aplacard, the name of the hazardous material is sten-ciled on two sides of the car. In addition, by looking atthe sides of a railcar, a firefighter can learn the specifi-cation type, maximum quantities, test pressures, reliefvalve settings, and other pertinent information. Thesetypes of markings are shown in Figure 25-67.

Figure 25-64 This railcar is white with a red stripe,which is used to indicate hydrogen cyanide but onoccasion is used to indicate dangerous materials. Thiscar holds hydrogen fluoride anhydrous, which is asevere inhalation hazard and is corrosive. The termanhydrous indicates “no water” and means the hydro-gen fluoride is pure.

Figure 25-65 The pressurized car is indicated by thevalves being contained within the protective housingof the railcar.

Figure 25-66 This specialized railcar holds liquefiedcarbon dioxide, a cryogenic material.

790 ■ CHAPTER 25

It used to be common practice to paint a car carry-ing hydrogen cyanide white with a red stripe runningaround the middle, hence the name “candy-striper.”

Bulk Storage TanksBulk storage tanks range in size from 250 gallonsup to millions of gallons and store a variety of prod-ucts, the most common being petroleum products.

Figure 25-68 The sizes of tanks vary from a few hundred gallons up to several milliongallons. A catastrophic failure of the tank may overwhelm the responders’ ability to han-dle the incident.

Note Certain railcars may be painted in a certainconfiguration to identify their hazardous loads.

Figure 25-67 A railcar has a lot of information stenciled on the side. The FMLX indentifies who owns the car. TheX at the end indicates that the car is privately owned, that is, the railroad does not own the car. The 15020 is thecar number and can be used to cross-reference the shipping papers. The photo on the left is the certification andtesting data. The top line DOT 111 A 100 W 1 provides most of the information. The tank is a DOT 111 specifica-tion, which means that it is a non-pressure car. The A indicates the type of couplers, and the 100 is the maximumpressure for the car. The W and the 1 indicate the type of welds and other tank construction information. The lastline is also important, and it shows that the tank was lined on 3-94, which means that it has an internal lining. In aderailment the lining could separate from the tank and the chemical could react with the tank metal.

These tanks are seen in residential homes and ruralareas, and are common at an industrial facility, suchas the one shown in Figure 25-68. In residentialhomes the most common tank is a 250-gallon homeheating oil tank, and some homes or small busi-nesses may have gasoline or diesel fuel tanks thatvary from 250 to 500 gallons.

The two basic groupings of tanks are in-groundand aboveground. Since the passage of the EPAunderground storage regulations, there has beenconsiderable movement to remove undergroundstorage tanks (USTs) and replace them withaboveground storage tanks (ASTs). If the facility


owner elects to keep its tanks underground thenadditional requirements are placed on them for test-ing, containment, and leak prevention.

can differentiate between unleaded, unleadedsuper, and diesel fuel, although the color coding isnot standard across the country and varies fromcompany to company. At some location on theproperty there will be vent pipes for the tanks,generally away from the pumps and near the prop-erty line. There will also be other manhole coversapproximately 6 to 8 inches in diameter that have atriangle on the top of the cover. These are inspec-tion wells and typically surround the tank. Theholes are drilled at various depths so that leaks canbe easily detected by air monitoring of the well, orif water is in the well, by taking a sample. If afacility has had a leak, there may be a large num-ber of these wells on and around the property.Most gas station tanks are 10,000 to 25,000 gal-lons in size and, if not properly monitored, canslowly release a substantial amount of productover a short period of time.

A substantial release from a million-gallon tank ofgasoline that escapes a facility would require anenormous response from the emergency respondersand environmental contractors.

Underground tanks are usually constructed ofsteel and are coated with an anticorrosion material.New tanks are usually double walled, that is, a tankwithin a tank, to prevent any spillage into the envi-ronment. The piping comes up through the groundand its use will determine its route. The offload pip-ing for an UST at a gasoline station comes upthrough the pump, which Figure 25-69 demon-strates. The piping is manufactured so that in theevent that a car knocks off the pump it will shut offthe flow of gasoline and will snap the piping off ator near the ground level. The only spillage of gaso-line would be from the amount in the piping above-ground and in the hose, if everything worksproperly. (See boxed text for more information.)

The loading piping is located separately and allof the fill pipes are located in the same area foreasy transfer from a tank truck. The fill pipes areusually color coded and marked so that the driver

Liquid Gasoline

VaporRecovery

Fill Cap Vent Sampling Well

Figure 25-69 Piping system of a gas station.

Note It is not uncommon to find gasolinebubbling up in a basement miles away from thegas station and to find that the release occurredseveral years ago.

Caution Leaks from these types of tanks canbe overwhelming because the leak may not bedetected for a period of time, giving it a chanceto spread throughout the area, contaminating alarge area.

Another common problem arises when farmsare redeveloped into housing developments. Ifunknown USTs are located on the property, theymay or may not be discovered during the con-struction and can eventually leak, causing prob-lems. The tank and environmental industry refersto a leaking underground storage tank as aLUST.

792 ■ CHAPTER 25

Aboveground tanks are becoming more and morecommon, although they have been used for manyyears, Figure 25-70. They are of two basic construc-tion types—upright and horizontal—and some arenonpressurized or atmospheric tanks and some arepressurized tanks. ASTs hold a wider variety of chem-icals as opposed to their UST counterparts, but petro-leum products are still a leading commodity stored inthese type of tanks. They vary in size from the 250-gallon home heating oil tank to the several milliongallon oil tank. In industrial and commercial applica-tions, a containment area is required around the tank.The containment area must be able to hold the con-tents of the largest tank within the containment. Regu-lar inspection of these areas is required to ensure thatrainwater, snow, or ice does not cause a buildup ofliquid in the containment area, which would reducethe containment’s ability to hold its intended amount.Depending on the weather conditions, the contain-ment area’s gate valve may be left in an open position,

Safety A recent incident in Baltimore County,Maryland, demonstrates that regardless of howmany protection systems may be in place, arelease off the property is still possible.

One afternoon a gas station was getting a tankfilled with fuel, as per normal procedure, and thetank filling went as expected with no problems.The gas station had installed a state-of-the-artalarm system that would indicate a fault in the sys-tem and alert the owners to any potentialreleases. The system goes through a system checkafter each sale, if no pump is operated for aperiod of thirty seconds. If a pump is on, or theperiod between sales is less than thirty seconds,then the system check does not begin to work.During a busy afternoon, it could be estimatedthat the system check would not function for along period of time, because at least one of thepumps is operating all the time.

In addition to the system check of each of thestorage tank locations, some piping and thepumps all have electronic monitors that detectthe presence of a l iquid. When a l iquid isdetected, an alarm activates—the same type ofalarm as if the system check fails the system. Oneof the potential problems with many self-servicegas stations is that there is only one attendant,who for many reasons cannot leave the work areato either check on a problem outside or, depend-ing on the alarm panel location, cannot check anyalarms. In some gas stations the alarms are inother rooms and cannot be seen or heard by theonly attendant. Another problem is that the liquid

alarms will activate when it rains, tripping for rain-water.

The pumps that sit on top of the storage tankshave the ability to supply upward of 80 psi of pres-sure to all pump station nozzles, although this isgoverned down to an actual working pressure of10 psi at all pumps. In this particular incident, aflange that comes out of the tank pump failed andseparated from the tank pump. From the pumpdischarge there is a 2-inch-diameter opening,which at 10 to 80 psi could pump a considerableamount of fuel in a short time. One theory is that acustomer may have set a nozzle down after notbeing able to pump fuel, or the amount of fuelbeing pumped was inadequate. This action wouldhave resulted in the tank pump continuing topump. A liquid alarm sounded for a number ofareas at the gas station. The attendant notified thepump repair company as per protocol, but aresponse was delayed due to a number of extenu-ating circumstances.

Once the repair company arrived they foundthe tank empty; it was at this time the clerkinformed them of the recent delivery. It was laterfound that an estimated 4,500 gallons were lostand were causing flammable vapor readings in aseveral-block area, although all the gasoline waslater recovered. Within the gas delivery system,this station had the best protection in place, andhad just retrofitted the station with a new pipingsystem, but it shows that no matter how many pro-tection systems are in place, it is still possible tohave a release.

Figure 25-70 Due to increased environmental con-cerns, many tanks are being placed aboveground andare called aboveground storage tanks or ASTs.


which leaves the facility at risk for product to escapethe facility through the open drain or gate valve.

Upright storage tanks come in three basic construc-tion types: ordinary tank, external floating rooftank, and internal floating roof tank. The ordinarytank, Figure 25-71, is constructed of steel and typi-cally has a sloped or cone roof to shed rainwater,snow, and ice. The roof and tank shell seam is pur-posely made weak so that in the event of an explosion,only the top of the tank is relocated. One of the majorproblems with this type of tank is that when the tank isnot full, there is room for vapors to accumulate.

Some ordinary tanks are purposely constructedwithout a roof in place. These are typically used insafety vent situations and water treatment areaswhere a roof may cause additional problems. It isimportant to identify these tanks during pre-incidentsurveys so as not to misjudge the severity of an inci-dent. In many chemical processes it is not uncom-mon to have a storage tank with piping into the tankjust to catch overflow or the contents of a system inthe event of overpressurization or failure. The mate-rials can be hot and produce large amount of vapors,which, if a roof were present, would allow a buildupof pressure, causing a catastrophic failure of thetank and roof.

External floating roof tanks are used to eliminatethe buildup of vapors. They ride on top of the liquid,Figure 25-72, and since there is no space betweenthe roof and the liquid, vapors cannot accumulateand create problems. External floaters can be seenfrom the top of the tanks, and a ladder is affixed tothe roof to allow access. A common incident withthese types of tanks results from a lightning strike,

which can cause a fire in the roof/shell interfacearea. This type of fire is difficult to extinguish andcan result in roof/tank failure if not controlledquickly. It is also possible that water used for fire-fighting could also sink the roof, causing furtherproblems.

Internal floaters are constructed in the samemanner as external floaters but have an additionalroof over the top of the tank. An example isshown in Figure 25-73. The type of roof varies,but is usually a slightly coned roof with ventholes along the outer edge of the tank shell, or ageodesic type of roof that is usually made offiberglass. The internal floater suffers from thesame type of fire problem as the external,although it is a reduced risk. If a fire were to startin the roof/shell interface, the roof makes it moredifficult to extinguish.

Figure 25-73 This is a covered floating roof tank,which is the same as an open floating roof tank but hasa cover to keep out snow, rain, and debris. Anotherterm for this type of tank is geodesic domed tank.

Caution Any time vapors are allowed to accu-mulate, the potential exists for a fire or explosion.

Figure 25-71 This is a cone roof tank. It has a weakroof-to-shell seam so that in the event of an explosionthe roof will come off, but the tank should remain intact.

Figure 25-72 This is an open floating roof tank, inwhich the roof floats on top of the product. Thisreduces the release of vapors, as there is no vaporspace, and reduces the fire potential.

Most hospitals are supplied with liquid oxygen(LOX) through the cryogenic tank. Facilities thatsell or distribute compressed gases are likely to havecryogenic tanks. Fast-food restaurants and conven-ience stores are now using cryogenic tanks to supplycarbon dioxide to the soda dispensing machines.

SENSESVision and hearing are acceptable senses to usewhile investigating potential chemical releases. Theuse of touch, smell, and taste, however, is a danger-ous use of the senses.

794 ■ CHAPTER 25

Specialized TanksSpecialized tanks are a combination of the tank typesdiscussed earlier in this section and include pressur-ized tanks and cryogenic tanks. The larger pressurizedvessels are divided into two categories: low-pressureand high-pressure tanks. The low-pressure tanks holdflammable liquids, corrosive liquids, and some gases,up to 15 psig. Common high-pressure commoditiesare liquefied propane, liquefied natural gas, or othergaseous or liquefied petroleum gases. An acid likehydrochloric acid, which has a high vapor pressure,would not be uncommon in a tank like this.

These types of tanks may have an external cover,which appears to be a tank within a tank. The pressur-ized tanks are larger versions of the propane tanks dis-cussed earlier and can have a capacity of up to 9million gallons although less than 40,000 gallons istypical. Liquefied petroleum gases are not only storedin pressurized tanks such as the one shown in Figure25-74; these types of gases are also stored in otherlocations such as caves carved out of mountains,although this is rare. Because these facilities are notrequired to report under the SARA Title III regula-tions, firefighters will have to contact their local gassuppliers to find out how they store their gas products.

Upright cryogenic storage tanks, Figure 25-75,are located in almost every community, especially ifthe community has a hospital or medical center.

Figure 25-75 This tank holds cryogenic liquid oxy-gen and is typical of a cryogenic upright tank.

Figure 25-74 The specialized tank such as thepropane tank shown here has some of the same prop-erties as its transportation equivalents.

Caution The lack of an odor cannot beequated with a lack of toxicity. Many severelytoxic materials are colorless and odorless.

Sensory clues gained from other persons are use-ful to help identify the spilled material. The smell ofmaterials is an important clue when trying to iden-tify a spilled material, so if bystanders or evacuatedpersons can assist by describing an odor, firefightersshould take advantage of this clue, but they shouldnot endanger their lives to determine an odor. Manytoxic materials can be harmful if touched becausethe material can be absorbed through the skin. Any-


time a person handles a chemical, appropriatechemical protective clothing should be worn.

CHEMICAL ANDPHYSICAL PROPERTIES

Although not intended to be a full chemistry lesson,the material in this section is a key component ofsafety. The chemical and physical properties out-lined here are appropriate for a firefighter’s level ofresponse. The identification and use of these keyterms can determine the outcome of an incident andfirefighter well-being. As a firefighter progresses upthrough the response levels the need for additionalchemistry also increases. When in doubt, the fire-fighter should consult with a HAZMAT team orother resources such as Chemtrec or a local special-ist. A lot of the terms to be discussed next can beapplied throughout the entire firefighter text. Thebasis of a fire is a chemical reaction. The better thatfirefighters understand this chemical reaction, thebetter off they will be, which will also benefit thecitizens of their communities.

States of MatterThe basic chemical and physical properties that areimportant to understand are the states of matter:solid, liquid, and gas as shown in Figure 25-76.The severity of an incident can be determined byknowing if the material is a solid chunk of stuff, apool of liquid, or an invisible gas.

The control methodology for each state increases indifficulty from simple controls with a solid, to diffi-cult with a gas. Evacuations have to be larger forreleases involving gases, whereas a minimal evacua-tion would be required for most solid materials.

How the chemicals can hurt someone also varieswith the state of material. Solids usually can onlyenter the body through contact or ingestion,although inhalation of dusts is possible. Liquids canbe ingested, absorbed through the skin, and, if evap-orating, inhaled. Gases on the other hand can beabsorbed through the skin, and inhaled, and to someextent ingested.

Adjoining the states of matter are melting point,freezing point, Figure 25-77, boiling point,Figure 25-78, and condensation point. All of theseare related because they are the points at which amaterial changes its state. The melting point is thetemperature at which solid must be heated to trans-form the solid to the liquid state. Ice, for instance,has a melting point of 32°F. The freezing point isthe temperature of a liquid when it is transformedinto a solid. For water, the freezing point is 32°F.The actual temperatures vary by the tenths of adegree, but are very close. The boiling point isreached when the liquid is heated to the point atwhich evaporization takes place, that is, the liquid

Block Balls

Solids Can Existin a Variety of Forms

Liquids Gases

Cylinder

Dust/Dirt Pile

Figure 25-76 States of matter.

Note The level of concern rises with eachchange of state; relatively speaking, a release ofa solid material is much easier to handle than aliquid release, and it is nearly impossible to con-trol a gas.

796 ■ CHAPTER 25

thing to remember about boiling points is the factthat when the liquid approaches this temperature,vapors are being produced that can cause largerproblems.

Vapor PressureOut of all of the chemical and physical properties,vapor pressure is one of the most important to a haz-ardous materials responder. If a product has a highvapor pressure, it can be very dangerous. A mate-rial with a low vapor pressure is typically not amajor concern. Vapor pressure has to do with theamount of vapors released from a liquid or a solid,Figure 25-79. The true definition is the pressure thatis exerted on a closed container by the vapors com-ing from the liquid or solid. Vapor pressure can berelated with the ability of a material to evaporate, inthat the material is not really disappearing, it is justmoving to another state of matter. Chemicals likegasoline, acetone, and alcohol all have high vaporpressures, whereas diesel fuel, motor oil, and waterall have low vapor pressures.

Vapor pressures are measured in three ways: mil-limeters of mercury (mm Hg), pounds per squareinch (psi), and atmospheres (atm). Normal or aver-

Lid

Liquid

A material with a vapor pressure is pushing against the sides of the container. If the vapor pressure is high and the material is in the wrong type of container, the container could fail.

Figure 25-79 Vapor pressure.

Temperature

°F

32°F

Melting Point

Temperature

°F

32°F

Freezing Point

Melting Ice

LiquidWater

Figure 25-77 Melting and freezing points.

Thermometer212°F

Water

Flame

Figure 25-78 Boiling point.

is being changed into a gas. Another way of defin-ing boiling point is the temperature of a liquid whenthe vapor pressure exceeds the atmospheric pres-sure and a gas is produced. Water boils at 212°Fand changes into a gaseous state. The important


age vapor pressures are 760 mm Hg, 14.7 psi, and1 atm. Although these figures are used to describenormal vapor pressure, they best describe atmos-pheric pressure. The temperature which is used is68°F (20°C), which is the standard temperature. Ifa temperature is not provided, then it can beassumed it is 68°F. Chemicals that have a truevapor hazard are those in excess of 40 mm Hg, andthey are considered volatile. Chemicals with avapor pressure of less than 40 mm Hg do not pres-ent much inhalation hazard even though they canstill present extreme toxicity through skin absorp-tion. Chemicals with a vapor pressure above40 mm Hg can be considered inhalation hazards inaddition to any other route of exposure they maypossess. Table 25-9 lists vapor pressures for somecommon products.

A unique chemical phenomenon called sublima-tion occurs when a chemical goes from a solidstate of matter to a gas. The material never entersthe liquid phase. The sublimation ability meansthat some solids have a vapor pressure and canmove directly to the gaseous stage. Some solidssuch as dry ice (carbon dioxide) move quickly tothe gaseous stage, while others, such as mothballs(naphthalene or paradichlorobenzene), moveslowly.

Vapor DensityIt is easy to confuse vapor pressure with vapor den-sity, but they have two entirely different meanings.Vapor density determines whether the vapors willrise or fall, Figure 25-80. When deciding on poten-tial evacuations and other tactical objectives (e.g.,sampling and monitoring) this is an important con-

sideration. One of the primary reasons that naturalgas leaks do not ignite or flash back more often isthe vapor density of natural gas. Air is given a valueof 1, and all other gases are compared to air. Gasesthat have a vapor density of less than 1 will rise inair and will dissipate, whereas gases with a vapordensity greater than 1 will stay low to the ground.Natural gas has a vapor density of 0.5, whilepropane has a vapor density of 1.56, which causes itto seek out any low spots, like gullies or sewers.Propane is more likely to ignite or flash backbecause it has a greater potential of finding an igni-tion source.

Common Products and Their Vapor PressuresNAME VAPOR PRESSURE @ 68°F (MM HG) BOILING POINT (°F)

Water 25* 212

Acetone 180 134

Gasoline 300–400 399

Diesel fuel 2–5 304–574

Methyl alcohol 100 149

Ethion (pesticide) 0.0000015 304 (decomposes)

Sarin nerve agent 2.1 316

*The vapor pressure of water has been reported in various texts as between 17 and 25 mm Hg. This text uses 25, as it is the high-est reported vapor pressure for water.

400GAS 400GAS

Vapor Density Less than 1 WillRise in Air

Vapor Density Greater than 1 Will Sink

Air � 1

Figure 25-80 Vapor density.

TABLE 25-9

798 ■ CHAPTER 25

Specific GravityThis chemical property is similar to vapor density inthat it determines whether a material sinks or floatsin water, Figure 25-81. Specific gravity is of primeconcern when efforts are being taken to limit thespread of a spill by the use of booms or absorbentmaterial. Water is given a value of 1, and chemicalsthat have a specific gravity of less than 1 will floaton water. Fuels, oils, and other common hydrocar-bons (chemicals composed of hydrogen and carbon,typically combustible and flammable liquids) have aspecific gravity of less than 1 and, hence, will floaton water.

Materials that have a specific gravity of greaterthan 1 will sink in water. It is much easier torecover materials floating on top of the water asopposed to those underwater. Carbon disulfide and

1,1,1-trichloroethane are two common materialsthat sink in water. Any material that sinks in wateris especially troublesome if it has the potential toreach any groundwater, because remediation(cleanup) efforts are difficult and expensive.

Also of concern are materials that are water solu-ble, that is, have the ability to mix with water, notsink or float. Corrosives and many poisons are watersoluble and are difficult to remove from a watersource. Examples are provided in the following Fire-fighter Fact. Alcohol is also water soluble. Materialsthat are water soluble are difficult to extinguish.

CorrosivityThis text has already discussed tanks and contain-ers that hold corrosives, as well as the concerns ofdealing with corrosives. Corrosive is a term that is

Firefighter Fact When dealing with water-soluble materials it is important to protect bodiesof water, because the cleanup can be difficult orimpossible if the material enters the water. In oneincident more than 10,000 gallons of sodiumhydroxide, a very corrosive material, entered asmall stream. The creek had to be dammed, and aneutralizing agent was put into the stream. Any lifeexisting in this mile of stream was killed by thesodium hydroxide, but the environmental damagecould have spread for many more miles if it hadnot been neutralized. Once neutral, the water wasreleased, which eventually led to a larger body ofwater, where no damage occurred. This took con-siderable resources and time to accomplish, andluckily the necessary neutralizing agent waslocated at the site of the spill.

In another incident a very small amount of a pes-ticide was sprayed near a pond. After a rainfall thepesticide ran into the pond, killing all of the fish.The only method of removing this pesticide is theaddition of other chemicals that are also haz-ardous. It will be years before the pond is able tosustain life.

In another incident in Baltimore City a railcar wasinvolved in an accident and released 18,000 gal-lons of hydrochloric acid, which eventually ran intoa local stream. The addition of the acid actuallyraised the pH level of the stream to near accept-able levels, because this stream was already heavilycontaminated from a number of other sources.

Note that nothing should be flushed into anybody of water without the express permission ofthe local or state environmental agencies.

A Material with a Specific Gravity of Less than 1 Will Float on Water

PondMaterial with a Specific Gravity ofGreater than 1 Will Sink in Water

Figure 25-81 Specific gravity.


applied to both acids and bases, and is used todescribe a material that has the potential to corrodeor eat away skin or metal. Some examples areshown in Table 25-10. People deal with corrosivesevery day in that the human body is naturallyacidic and they use many corrosive materials intheir everyday lives. Acids are sometimes referredto as corrosives, whereas bases are also known asalkalis or caustics. The accurate way to describe acorrosive is to identify the material’s pH, whichprovides some measure of corrosiveness. pH is anabbreviation for positive hydronium ions. It is usedto designate the corrosive nature of a material.Acids have hydronium ions, and bases have hydrox-ide ions. It is the percent (ratio) of these ions thatmakes up the pH number. Materials having a pH of0 to 6.9 are considered acids, and materials with apH of 7.1 to 14 are considered bases. A materialhaving a pH of 7 is considered neutral. The pHscale is a logarithmic scale, meaning the movementfrom 0 to 1 is an increase of 10. The movementfrom 0 to 2 is an increase of 100.

When dealing with a corrosive response, one ofthe common methods to mitigate the release is toneutralize the corrosive. One thought is that watercan be used to dilute and thereby neutralize thespill. This presents two major issues: one, the mix-ing of water (chemical reaction), and two, the runofffrom the reaction. Corrosives and water can be adangerous combination. One should never add acorrosive to water, as it presents great risk. Theremay be some spattering and heat generation.

If 1 gallon of an acid had a pH of 0, it would take10 gallons of water to move the material to a pH of1. To move it to a pH of 2 would take 100 gallons ofwater, and to change the pH to 6 would require 1

million gallons of water—all for a 1-gallon spill.Chemically neutralizing a corrosive spill is the bet-ter choice, but even that can present some issues.When neutralizing a strong acid, a weak baseshould be used to perform the neutralization. Astreet method of calculation for neutralization is thatit takes more than 8,800 pounds of potash to bring1,000 gallons of 50 percent sulfuric acid to neutral,which is more realistic than controlling 1 milliongallons of runoff. These examples are provided forinformation only; the neutralization of corrosives isa technician-level skill and can be very dangerous.

If the skin or eyes are exposed to a corrosivematerial, they should be immediately flushed withlarge quantities of water. This flushing should con-tinue for at least twenty minutes uninterrupted.Some corrosive materials will cause immediateblindness and skin burns, and water should be usedto prevent further injury.

Chemical ReactivityChemicals when they mix will have one of threetypes of reactions: exothermic, endothermic, or noreaction. The most common is the exothermicreaction, meaning the release of heat.

As discussed in Chapter 4, fire is a rapid oxida-tion reaction (exothermic) accompanied by heat andlight. When most chemicals mix and provide anexothermic reaction there usually is not a lot of lightbut there can be substantial heat. By mixing onetablespoon each of vinegar (acetic acid) and ammo-nia (base) at the same temperature, an immediaterise in temperature of 10°F will occur. When hand-ling oleum (concentrated sulfuric acid) and applyingwater to a spill, the resulting mixture will bubble,

TABLE 25-10

pH of Common MaterialsMATERIAL pH MATERIAL pH

Water* 7 Sulfuric acid 1

Stomach acid 2 Gasoline 7

Orange juice† 2 Hydrochloric acid 0

Drain cleaner** 14 Pepsi‡ 2

Potassium hydroxide 14 Household ammonia*** 14

*Tap water is usually a 7, while rainwater in the Northeast can be 3–6 (acid rain).†Citric acid is the main ingredient.**The main ingredient is sodium hydroxide (lye).‡Phosphoric acid is the main ingredient.***This is a 5 percent solution of ammonium hydroxide and water.

fume, boil, and heat to over 300°F the instant thewater hits the acid. An endothermic reaction is onein which the energy created by the reaction isabsorbed and cooling occurs.

Flash PointA flash point is described as the temperature of aliquid at which, when heated by an ignition source,a flash fire occurs, Table 25-11. This resulting flashfire will ignite just the vapors and self-extinguishonce those vapors are burned up. The liquid itselfdoes not burn; it is the mixture of vapors and airthat ignites. Following closely behind the flashpoint is the fire point of a liquid. The fire point isthe temperature of the liquid at which, when heated,vapors are produced that when ignited will sustainburning. In the laboratory, scientists can replicateflash points and fire points; on the street, however,they are usually one and the same.

Autoignition TemperatureSometimes referred to as ignition temperature, theautoignition temperature is the temperature at whicha material will ignite on its own without an ignitionsource. Ignition temperatures are much higher thanflash points and represent a potential hazard leveldepending on the temperature. Depending on thecontext, the term self-accelerating decompositiontemperature (SADT) may be used, which is essen-tially the same thing as the autoignition temperature.Regardless of what it is called, it is a level to avoid.

Flammable RangeThe two main areas within a flammable range arethe lower explosive limit and upper explosive limit.The flammable range is the difference between thetwo extremes. A fire or explosion needs an ignitionsource, a fuel (vapors), and air. The proper vapor-to-air ratio is also required or ignition cannot occur.The lower explosive (flammable) limit (LEL) isthe lowest amount of vapor mixed with air that canprovide the proper mixture for a fire or explosion.

800 ■ CHAPTER 25

The air monitor that is used to detect combustiblegases is designed to read this level. The upperexplosive (flammable) limit (UEL) is the highestamount of vapor mixed with air that will sustain afire or explosion.

Each year many natural gas explosions occurthroughout the United States. The LEL of natural gasis 5 percent, so if it is mixed with 95 percent air withan ignition source present an explosion or fire is possi-ble, as shown in Figure 25-82. The UEL for naturalgas is 15 percent, so 85 percent air is required to resultin a fire or explosion. The flammable range for naturalgas is 5 to 15 percent, and a fire or explosion canoccur at any point in that range, as long as there isenough air to complete the mixture. With 4 percentmethane and 96 percent air, there would not be anyfire or explosion nor would there be at 16 percent nat-ural gas and 84 percent air. Acetylene, which is a com-mon gas, has a LEL of 2.5 percent and UEL of 100percent, which means that when 2.5 percent LEL isreached, the potential for a fire exists. Having lessthan the LEL is referred to as too lean, and amounts inexcess of the UEL are called too rich. Levels less thanthe LEL are much safer than levels above the UEL.

Safety When confronted with a situation thathas a level higher than the UEL, the situation isvery dangerous.

TABLE 25-11

Ventilation should be carried out using non-spark-inducing devices, and great care should betaken to minimize any potential electrical arcs suchas not using light switches or doorbells.

Toxic Products of CombustionThis is the one area in which firefighters sufferconsiderable chemical exposures. Any time a per-son is in smoke or breathes smoke, the body isbeing bombarded with toxic chemicals. Manytoxic chemicals, such as carbon monoxide, carbondioxide, hydrogen cyanide, hydrochloric acid, andphosgene, are produced in a fire. The worst type

Flash Points of Some Common MaterialsMATERIAL FLASH POINT (°F) MATERIAL FLASH POINT (°F)

Gasoline �45 Diesel fuel �100

Isopropyl alcohol 53 Motor oil 300–450

Acetone �4 Xylene 90


of chemical accident a firefighter can respond tois a house, car, or Dumpster fire. Even brush firesare not exempt from the toxic products of com-bustion, because the field may have been sprayedwith pesticides, herbicides, or other chemicals.

Even burning wool or hay produces extremelytoxic gases. Due to this constant exposure to theseand other materials, it is important for firefightersto wear all of their protective clothing, especiallythe SCBA.

The ability to recognize and identify the poten-tial for hazardous materials to be present at anincident is important for the first responder. Thenumbers of tank trucks, tank cars, and contain-ers can easily overwhelm the beginning stu-dent. At any incident there is always a factorthat relates to the recognition and identificationprocess, whether it is the location, placards,container type, or physical senses. It could evenbe that sixth sense that alerts people to a

potential problem. When that occurs, it isimportant to proceed with caution.

One of the important lessons for respondersto remember is that they do not have to commiteverything to memory, but they should knowwhere to access hazardous materials informa-tion. It is not expected that each communityhave a railcar expert in their fire department.What is expected is that each fire departmenthave a contact person available around the

Methane5%

Methane15%

Methane4%

Methane17%

Air95%

Air85%

Air96%

Air83%

To have a fire or explosion the lower explosive limit must be reached. Each gas has a flammable range in which there can be a fire or explosion. Below the LEL or above the UEL means there cannot be a fire.

Flammable Range

Too Lean to Burn

Too Rich to Burn

MethaneLEL � 5% UEL � 15%

Figure 25-82 Flammable range.

802 ■ CHAPTER 25

vapor pressures do present a great risk toresponders and to the community and shouldbe treated with caution. Vapor pressure is onlyone of the terms with which responders shouldbecome familiar. Local HAZMAT responders area good resource and should be contacted earlyin an incident and whenever assistance dealingwith hazardous materials is needed.

clock to obtain that resource. It is possible thatevery material on this earth has the ability tocause harm in some fashion, but the chemicaland physical properties play a factor in the typeof harm that can be caused.

Materials that have low vapor pressurespresent little risk to the responders unlesstouched or eaten. Materials that have high

KEY TERMSAboveground Storage Tank (AST) Tank that is

stored above the ground in a horizontal or verti-cal position. Smaller quantities of fuels areoften stored in this fashion.

Boiling Point The temperature to which a liquidmust be heated in order to turn into a gas.

Building Officials Conference Association(BOCA) A group that establishes minimumbuilding and fire safety standards.

Bulk Tank A large transportable tank, comparableto a tote, but considered to be the larger of thetwo.

Chemtrec The Chemical Transportation Emer-gency Center, which provides technical assis-tance and guidance in the event of a chemicalemergency; a network of chemical manufactur-ers that provide emergency information andresponse teams if necessary.

Cryogenic Gas Any gas that exists as a liquid at avery cold temperature, always below �150°F.

Deflagrates Rapid burning, which in reality withregard to explosions can be considered a slowexplosion, but is traveling at a lesser speed thana detonation.

Emergency Response Guidebook (ERG) Bookprovided by the DOT that assists the first respon-der in making decisions at a transportation-related chemical incident.

Endothermic Reaction A chemical reaction inwhich heat is absorbed, and the resulting mix-ture is cold.

Exothermic Reaction A chemical reaction thatreleases heat, such as when two chemicals aremixed and the resulting mixture is hot.

External Floating Roof Tank Tank with the roofexposed on the outside that covers the liquidwithin the tank. The roof floats on the top ofthe liquid, which does not allow for vapors tobuild up.

First Responders A group designated by thecommunity as those who may be the first to

arrive at a chemical incident. This group is usu-ally composed of police officers, EMSproviders, and firefighters.

Frangible Disk A type of pressure-relievingdevice that actually ruptures in order to vent theexcess pressure. Once opened the disk remainsopen; it does not close after the pressure isreleased.

Freezing Point The temperature at which liquidsbecome solids.

Gas A state of matter that describes the materialin a form that moves freely about and is difficultto control. Steam is an example.

Ignition Temperature The temperature of a liq-uid at which it will ignite on its own without anignition source. Can be compared to SADT.

Intermodal Containers These are constructed ina fashion so that they can be transported byhighway, rail, or ship. Intermodal containersexist for solids, liquids, and gases.

Internal Floating Roof Tank Tank with a roofthat floats on the surface of the stored liquid,but also has a cover on top of the tank, so as toprotect the top of the floating roof.

Leaking Underground Storage Tank (LUST)Describes a leaking tank that is underground.

Liquid A state of matter that implies fluidity,which means a material has the ability to moveas water would. There are varying states ofbeing a liquid from moving very quickly to veryslowly. Water is an example.

Lower Explosive Limit (LEL) The lower part ofthe flammable range, and is the minimumrequired to have a fire or explosion.

Melting Point The temperature at which solidsbecome liquids.

Ordinary Tank A horizontal or vertical tank thatusually contains combustible or other less haz-ardous chemicals. Flammable materials andother hazardous chemicals may be stored insmaller quantities in these types of tanks.


Relief Valve A device designed to vent pressure ina tank, so that the tank itself does not rupturedue to an increase in pressure. In most casesthese devices are spring loaded so that when thepressure decreases the valve shuts, keeping thechemical inside the tank.

Reportable Quantity (RQ) Both the EPA andDOT use the term. It is a quantity of chemicalsthat may require some type of action, such asreporting an inventory or reporting an accidentinvolving a certain amount of the chemical.

Sea Containers Shipping boxes that weredesigned to be stacked on a ship, then placedonto a truck or railcar.

Self-Accelerating Decomposition Temperature(SADT) Temperature at which a materialwill ignite itself without an ignition sourcepresent. Can be compared to ignition temperature.

Solid A state of matter that describes materials thatmay exist in chunks, blocks, chips, crystals, pow-ders, dusts, and other types. Ice is an example.

Specification (Spec) Plates All trucks and tankshave a specification plate that outlines the typeof tank, capacity, construction, and testing information.

States of Matter Describe in what form matterexists, such as solids, liquids, or gases.

Sublimation The ability of a solid to go to the gasphase without being liquid.

Tote A large tank usually 250 to 500 gallons, con-structed to be transported to a facility anddropped for use.

Underground Storage Tank (UST) Tank that isburied under the ground. The most common aregasoline and other fuel tanks.

Upper Explosive Limit (UEL) The upper part ofthe flammable range. Above the UEL, fire or anexplosion cannot occur because there is toomuch fuel and not enough oxygen.

Vapor Pressure The amount of force that is push-ing vapors from a liquid. The higher the forcethe more vapors (gas) being put into the air.

1. What are the nine hazard classes as defined byDOT?

2. An explosive placard is what color?3. What three things on a placard indicate the

potential hazards?4. A DOT-406/MC-306 tank truck commonly car-

ries what product?5. A DOT-406 tank truck has a characteristic shape

from the rear. What is it?6. An MC-331 carries what type of gases?7. What does the blue section of the NFPA 704

system refer to?

8. What are the locations of emergency shutoffs onan MC-331?

9. What are the four basic clues to recognition andidentification?

10. The Table 25-1 placards are required for whatquantities?

11. A tractor trailer carrying Division 1.1 materialsis well involved in fire. What should be the fire-fighter’s initial tactics?

12. When propane tanks are involved in a fire, whatis a potential consequence?

REVIEW QUESTIONS

Bevelacqua, Armando, Hazardous MaterialsChemistry. Delmar Learning, a part ofthe Thomson Corporation, Clifton Park,NY, 2001.

Bevelacqua, Armando and Richard Stilp,Hazardous Materials Field Guide.

Delmar Learning, a part of theThomson Corporation, Clifton Park,NY, 1998.

Bevelacqua, Armando S. and Richard H.Stilp, Terrorism Handbook forOperational Responders, 2nd ed.

Delmar Learning, a part of the ThomsonCorporation, Clifton Park, NY, 2004.

Hawley, Chris, Hadardous MaterialsIncidents, 2nd ed. Delmar Learning, apart of the Thomson Corporation,Clifton Park, NY, 2004.

Additional Resources

1. A tank truck placarded for gasolinecould also haul diesel fuel or fuel oilwithout having to change placards.

2. The requirements for the subdivisionsare presented in general. Other require-ments may need to be met for a material

to be assigned to a subdivision. Refer to49 CFR 170–180 for more information.

Endnotes

804 ■ CHAPTER 25

Hawley, Chris, HazMat Air Monitoring &Detection Devices. Delmar Learning, apart of the Thomson Corporation,Clifton Park, NY, 2002.

Henry, Timothy V. Decontamination forHazardous Materials Emergencies,Delmar Learning, a part of theThomson Corporation, Clifton Park,NY, 1999.

Lesak, David, Hazardous MaterialsStrategies and Tactics. Prentice Hall,1998.

Noll, Gregory, Michael Hildebrand, andJames Yvorra, Hazardous MaterialsManaging the Incident. Fire ProtectionPublications, Oklahoma University, 1995.

Schnepp, Rob and Paul Gantt, HazardousMaterials: Regulations, Response & Site

Operations. Delmar Learning, a part ofthe Thomson Corporation, Clifton Park,NY, 1999.

Stilp, Richard and Armando Bevelacqua,Emergency Medical Response toHazardous Materials Incidents.Delmar Learning, a part of theThomson Corporation, Clifton Park,NY, 1997.

chapter 25 · 2006-05-05 · hazardous materials: recognition and identification christopher...

Documents