chapter 35 perspectives on specific substances: sulfuric...

35.1

CHAPTER 35PERSPECTIVES ON SPECIFICSUBSTANCES: SULFURIC ACID

Richard Lawuyi and Merv FingasEmergencies Science Division, Environment Canada,Environmental Technology Centre, River Road,Ottawa, Ontario

35.1 OVERVIEW OF PRODUCT AND INDUSTRIAL USES

Sulfuric acid is a corrosive, oily, and colorless liquid well known since the Middle Ages. Itis a good dehydrating and drying agent and has been an important commercial commodityfor more than three centuries. Until the late 1960s, sulfuric acid production and consumptionwere generally accepted throughout the industrialized world as an accurate barometer of anation’s commercial activity and wealth. Nowadays, because of its extensive use in theagriculture industry, sulfuric acid no longer measures a country’s wealth. Nevertheless, moresulfuric acid is produced and spilled in the chemical industry today than any other chemical.It is indispensable in many chemical and industrial processes. The market for sulfuric acidis still very strong and will continue to grow.

Canada has an abundant supply of sulfur deposits, and sulfur occurs naturally in naturalgas and metal ores. Sulfuric acid can therefore be produced cheaply for both domestic useand export. Sulfuric acid is used primarily to produce phosphate fertilizers by the phosphoricacid route. It also has many uses in the processing industry, including kraft bleaching; incopper, petroleum, and uranium refineries; to manufacture various salts such as magnesiumsulfate; to manufacture soaps and detergents; in electroplating and metallurgy; and to producevarious chemical reagents such as phenols, alums, alkylation catalysts, explosives, propel-lants, fibers, electronic chips, pharmaceuticals, and acid batteries.

35.1.1 Modern Industrial Uses

The estimated consumption of sulfuric acid in 1996 by the industrial sector in the UnitedStates is shown in Figure 35.1. In Canada, while fertilizer consumption is not as prominent,consumption of sulfuric acid follows a similar pattern to that in the United States: fertiliz-ers—68%; mining—5.8%; miscellaneous—10.6%; inorganics—5.1%; others, including pe-troleum refining and products, synthetic rubber and plastics, pulp mills and other paperproducts, and industrial organic chemicals—10.5% (CIS, 1997). Sulfuric acid consumptionis very stable and should continue to be so.

35.2 CHAPTER THIRTY-FIVE

Others

Inorganics

MiscellaneousMining

Fertilizers

FIGURE 35.1 Uses of sulfuric acid in the United States in 1996.

35.2 INTRODUCTION

Sulfuric acid was apparently discovered in the 8th century by a Persian alchemist whodistilled niter (potassium nitrate) with green vitriol (ferrous sulfate crystals) obtained fromweathered iron pyrites. Several alchemists, including Jabir ibn Hayyan, Vincentius de Beau-vais (1240), Albertus Magnus (1193–1280), Paracelsus, Gerhard Dornaeus (1570), AndreasLibavius (1595), Angelus Sala (1613), Nicholas le Fevre (1666), Nicholas Lemery, andCornelius Drebbel, tried to improve on his methodology.

By the middle of the 12th century, Occidental alchemists were also producing sulfuricacid from sulfur and pyrites. Following Lavoisier’s discovery in the 18th century that sulfuris a chemical element and not a mixture, production of sulfuric acid from sulfur and pyriteswas commercialized in many parts of the world (Duecker and West, 1959).

In approximately 1740 in Great Britain, Ward began to produce the acid on a large-scaleby burning sulfur with potassium nitrate. In 1746, Dr. Roebuck of Birmingham introducedthe lead chamber process and built a factory in Scotland to manufacture the acid. Thispractice quickly spread throughout Europe and North America

In North America, commercial production of sulfuric acid began in 1797 when JohnHarrison built a sulfuric acid plant in Philadelphia. Much research has since been done onthe nature of the catalyst and feedstock. In the late 1800s, the lead chamber process wasgradually replaced by the contact process, patented by Phillips in 1831. In 1875, Emil Jacobsuccessfully demonstrated the new process and the modern contact acid manufacture of theacid began with a pyrite-burning gas as the source of sulfur dioxide.

Today, a large proportion of the sulfuric acid produced in the world is what is termed‘‘fatal’’ acid, which is manufactured to prevent substantial amounts of waste sulfur dioxideformed in metallurgical and smelting processes, such as nonferrous metal smelting and ironproduction from pyrites, from entering the environment (Inco Limited, 1985; Muller, 1997).

PERSPECTIVES ON SPECIFIC SUBSTANCES: SULFURIC ACID 35.3

Many of the environmental and technical problems associated with the large-scale produc-tion, handling, and shipment of sulfuric acid are now fairly well understood. Today, emis-sions, effluent discharge, handling, and shipping are governed by national and internationalregulations and codes.

35.2.1 Spill Profile

For the last few years, sulfuric acid has been one of the most commonly spilled substances(Environment Canada, 2000). The annual frequency of spills of sulfuric acid from 1990 to1996 is shown in Figure 35.2. It can be seen that the number of spills is slowly decreasing.Chemical burns are the most prevalent hazard from spills of sulfuric acid. Its main properties,including physical, chemical, toxicological, behavioral, and environmental fate, are outlinedin Section 35.3.

35.2.2 Priority List Ranking

According to a study to determine the minimum number of hazardous chemicals most fre-quently spilled, sulfuric acid is sixth on the list, with the highest supply volume (Fingas etal., 1991). It also has one of the highest numbers of spills. The priority list was developedby a simple ranking of: (1) reported spill frequency; (2) supply volumes; (3) historical spillvolumes; and (4) toxicities. Table 35.1 shows how sulfuric acid ranks in Environment Can-ada’s priority listing of hazardous chemicals.

35.3 PHYSICAL AND CHEMICAL PROPERTIES AND GUIDELINESSUMMARY

Sulfuric acid: Sulfuric acid is a colorless (when pure) to dark brown, oily liquid with asharp, penetrating odor.Molecular formula: H2SO4

Molecular weight: 98.08CAS number: 7664-93-9UN number: 1830

Fuming: 1831Spent: 1832

STCC number: 4930040Spent: 4930042

OHM-TADS number: 7216915Labels:

CorrosiveCorrosive and poison (fuming)–IMO

Synonyms and trade names (RTECS On-Line, 1999):


FIGURE 35.2 Spill profile of sulfuric acid (1990–1996).

TABLE 35.1 Priority List Ranking of Sulfuric Acid

Chemical RankingSpill

numbersSpill volume

(thousand tons)Supply volume(million tons)

Ammonia 1 107 470 3,700Chlorine 2 36 120 1,700Tetraethyllead 3 4 72 26Styrene 4 24 5,000 630PCBs 5 334 89 –Sulfuric acid 6 155 13,000 3,700Sodium cyanide 7 3 83 12Hydrochloric acid 8 123 3,300 170Potassium chloride 9 31 12,000 –Pentachlorophenol 10 19 110 1.5Phenol 11 10 14 68Zinc sulfate 12 3 68 1,500Phosphorus 13 16 46 68Toluene 14 13 110 430

Sulfuric AcidAcide sulfuriqueBattery acidElectrolyte acidFertilizer acidHydrogen sulfateOil of vitriolSpirit of sulfurSulphuric acidAcido solforicoBov


Dipping acidMatting acidNordhaausen acidSpent sulfuric acidSchwefelsaureloesungenVitriol brown oilZwavelzuuroplossingen

Fuming sulfuric acid (sulfuric acid with dissolved SO3):Disulfuric acidDithionic acidFuming sulfuric acidFuming sulfuric acidOleumPyrosulfuric acid

Grades and Purities (Kirk-Othmer, 1983; Budavari, 1989): Pure sulfuric acid is a col-orless, oily liquid. When impure, it is brownish. The pure acid decomposes intosulfur trioxide and water at 340�C. It is soluble in water and alcohol with evolutionof heat. Spent sulfuric acid is a black oily liquid. It is also soluble in water withrelease of heat. Impurities are iron, arsenic, sulfur dioxide, nitrogen compounds,chloride, and fluoride.

Grade Minimum purity mole %1 (liquid phase)

Commercial (technical) 75; 78; 88; 93; 96; 98 to 99; and 100Electrolyte-battery acid �93.19Chemically pure (CP) 95.5 to 96.5USP –Sulfuric acid (fuming) Sulfuric acid and SO3

20% oleum (104.5%); 40% oleum (109.0%);65% oleum (114.63%)

1Impurity is mostly water and some metals.

Strengths:

Sulfuric acid:

Degrees Baume % H2SO4

Specific gravityat 17.78�C Freezing point (�C)

52 65.13 1.5591 �40.058 74.36 1.6667 �44.060 77.67 1.7059 �8.066 93.19 1.8354 �32.0– 98.00 1.8438 3.0– 100.00 1.8392 10.0

Fuming sulfuric acid:

Oleum,% free SO3

% EquivalentH2SO4

Specific gravity(37.78) Freezing point (�C)

20.0 104.50 1.8820 �9.030.0 106.75 1.9156 15.540.0 109.00 1.9473 33.065.0 114.63 1.9820 3.6

100.0 122.50 1.8342 16.8


Physical data:Concentrated sulfuric acid:

Physical state: Liquid (Budavari, 1989)Boiling point: 330 � 0.5�C (100%)Melting point: 10.36�C (100%)Solubility (water): Infinity (heat evolved)Density, liquid: 1.841 (96 to 98%)Vapor pressure (mm Hg): 1 at 146�CSpecific gravity (water � 1): 1.841Flammability: Not flammableVapor density (air � 1): 3.4Behavior (in water): Sinks, reacts with heat evolutionOdor threshold and range: Low concentration is odorless; in fire, high concentration

emits SO3 with an odor threshold �1 mg/m3

Sulfuric acid solution in water 93 to 98%State (15�C, 1 atm): LiquidMelting point: �32�C (93%)Relative density: 1.8 (water � 1)Solubility in water: Infinity

Sulfuric acid is a dense, colorless liquid at room temperature. In the past, its concentrationwas described as a function of its specific gravity in degrees Baume (�Be). In the UnitedStates, the Baume scale is calculated using the following formula:

�Be � 145 � (145/specific gravity)

In Germany and France, the Baume scale is calculated using 144.3 as the constant. TheBaume scale includes only concentrations in the range of 0 to 93.19% H2SO4. The scaledoes not extend to higher concentrations ranging from 93 to 100% H2SO4.

Sulfuric acid:Appearance: Clear to cloudy fuming liquidUsual shipping state: LiquidPhysical state at room temperature and pressure: Liquid

Melting point:

% H2SO4 �C Be

65 �6465.13 �40.0 52�74.36 �44.0 58�75 �1277.67 �8.0 60�78 �3888 �2093 �3593.19 �32.0 66�96 �1498.00 3.0

100.00 10.0


% oleum �C

20.0 �9.030.0 15.540.0 33.065.0 3.6

100.0 17.2

Boiling point:% H2SO4 �C

98 34096 �31093 27975 �193

% oleum �C

20 142

Decomposition temperature: 340�C (Budavari, 1989)

Vapor pressure (mm Hg):% H2SO4 mm Hg

96 1 at 146�C93 1 at 145.8�C

Densities:Specific gravity:

%H2SO4 Density

96 1.8493 1.83588 1.5075 �1.674 at 15.5�C

�20% SO3 1.92

Vapor density (air � 1):% H2SO4 V.D.

96 �0.3 at 25�C93 3.4

Fire properties:Flammability: Nonflammable. Highly reactive and capable of igniting finely divided,

combustible materials on contact.Behavior in fire: Emits toxic fumes.Decomposition temperature: 340�C (Budavari, 1989).Decomposition products: Toxic fumes of sulfur oxides.

Other properties:Molecular weight: 98.08 (Budavari, 1989)Grades (minimum purity %):

Commercial (technical) 75%78%93%96%98 to 99%100%


Electrolyte battery acid �93.19Chemically pure (CP) 95.5 to 96.5USP –Fuming sulfuric acid (oleum) 80% H2SO4 � 20% SO3

60% H2SO4 � 40% SO3

35% H2SO4 � 65% SO3

Refractive index: 1.4297 (for 100% H2SO4)Viscosity:

Viscosity (cp)(for 100% H2SO4) Temp. �C

48.4 032.8 1525.4 2015.7 3011.5 40

8.82 507.22 606.09 705.19 80

Surface tension, 25�C(compared to water):

% wt H2SO4 mN/m

4.11 72.218.26 72.55

12.18 72.8017.66 73.3621.88 73.9129.07 74.8033.63 75.29

Surface tension, 20�C(with vapor or air):

% wt H2SO4 mN/m

98.5 55.1Hygroscopicity: HygroscopicLatent heat of fusion: 2360 cal /g mole (9.8 kJ/mole at melting point)Latent heat of vaporization: 56 kJ/mole (at boiling point)Heat of formation: �813.9 kJ/mole (25�C)Heat of solution: �971.5 kJ/kgHeat capacity (Cp) constant pressure: 138.9 J /mole�C (25�C)Coefficient of thermal expansion (20�C): 0.5758 � 10�3 (100% solution); 0.2835 �

10�3 (10.9% solution)Thermal conductivity (30�C): 90% 0.21

60% 0.2530% 0.30

Diffusivity: 1.97 � 10�5 cm2 /s (water, 25�C)pH of aqueous solution: 0.3, 1 N solution at 25�CEutectic compositions: 36% aqueous solution (freezing point, �64�C)

Solubility:Water: Soluble in water. Reacts violently with evolution of heat. Spattering occurs

when water is added to sulfuric acid.


Properties of sulfur trioxide (Kirk-Othmer, 1983):Critical temperature: 217.8�CCritical pressure: 8,208 kPaCritical density: 0.630 g/cm3

Triple point temperature (� phase): 16.8�CTriple point pressure (� phase): 21.13 kPaNormal boiling point: 44.8�CMelting point (� phase): 16.8�CTransition temperature: �183.0�CLiquid density (� phase at 20�C): 1.9224 g/cm3

Solid density (� phase at �10�C): 2.29 g/cm3

Liquid coefficient of thermal expansion, 18�C: 0.002005 per �CLiquid heat capacity at 30�C: 3.222 kJ/ (kg�C)Heat of formation of gas at 25�C: �395.76 (MJ � kg) /molFree energy of formation of gas at 25�C: �371.07 (MJ � kg) /molEntropy of gas at 25�C: 0.25666 (MJ � kg) / (mol � �C)Heat of dilution: 2.109 MJ/kgHeat of fusion, �: 324.0 kJ/kg

�: 151.6 kJ/kg�: 94.07 kJ/kg

Heat of sublimation, �: 0.8518 MJ/kg�: 0.7269 MJ/kg�: 0.7029 MJ/kg

Heat of vaporization (� liquid): 0.5843 MJ/kgDiffusion in air at 80�C: 0.000013 m/sLiquid dielectric constant at 18�C: 3.11Electric conductivity: Negligible

35.3.1 Summary of Chemical Properties and Behavior (Bailar et al., 1975)

Sulfuric acid is a strong mineral acid, one of the most important compounds of sulfur andone of the best known nonaqueous protonic solvents. The sulfur atoms are surrounded sym-metrically by four oxygen atoms and are therefore highly associated because of the strongintermolecular hydrogen bonding. At the boiling point, sulfuric acid solutions containing lessthan 85% H2SO4 evaporate water exclusively, while those containing more than 35% freeSO3 (oleum) evaporate sulfur trioxide exclusively. The vapor of sulfuric acid solutions inbetween these two concentrations (85% H2SO4 to �35% oleum) is a mixture of sulfuricacid, water, and sulfur trioxide.

Sulfuric acid is miscible with water in all concentrations. The heat of hydration is veryhigh, about 210 kcal /mole at infinite dilution. Sulfuric acid forms hydrates, such as H2SO4

� H2O, H2SO4 � 2H2O, and H2SO4 � 3H2O, in the presence of water.

35.3.2 Physiological Effects of Sulfuric Acid

The physiological effects of exposure to sulfuric acid fumes depend on the particle size ofthe aerosol. Thus, for a constant sulfuric acid aerosol concentration, the irritant action of theaerosol increases with aerosol particle size. Other factors are humidity, temperature, andprevious exposure. Several studies have shown that prolonged exposure to sulfuric acidcauses tooth erosion, while overexposure to sulfuric acid aerosols leads to pulmonary edema,chronic pulmonary fibrosis, residual bronchiectasis, and pulmonary emphysema. The thresh-


old limit value (TLV) for sulfuric acid mist for humans is 1 mg/m3. This threshold isrecommended to prevent injury to the teeth and pulmonary irritation at particle sizes likelyto occur in industrial settings. Eye contact may result in loss of vision, while skin contactmay produce severe necrosis. If ingested, gastric perforation and peritonitis may occur, pos-sibly followed by circulatory collapse. A few drops may be fatal if the acid gains access tothe trachea.

35.3.3 Main Hazards

General: Sulfuric acid is a very corrosive, colorless liquid that may exhibit violent chem-ical changes at elevated temperatures and pressures and may react violently with water.Inhalation of vapor may cause serious lung damage, and contact with eyes may result intotal loss of vision. Skin contact may cause burning and severe necrosis. Sulfuric acid ishighly reactive and capable of igniting finely divided combustible materials on contact.It will char wood and many other organic materials on contact and emits toxic fumeswhen heated.Human health: Sulfuric acid is corrosive to all body tissues. Inhalation can paralyze therespiratory system, contact with eyes may result in loss of vision, and skin contact mayresult in severe burns and necrosis. Swallowing may cause severe injury or death. Betweenone teaspoonful and half an ounce of the concentrated acid may be fatal if swallowed,and an even smaller quantity may be fatal if inhaled. Chronic exposure may cause tra-cheobronchitis, stomatitis, conjunctivitis, and gastritis. Gastric perforation and peritonitismay occur and may be followed by collapse of the circulatory system. Pulmonary fibrosis,bronchiectasis, and emphysema have been reported from acute exposure to fuming sul-furic acid and sulfuric acid mist. Chronic exposure usually results in erosion of the teeth,particularly the incisors.Environment: Sulfuric acid is a powerful acidic oxidizer and a strong dehydrating agent.It is harmful to many microorganisms, plants, and aquatic life in concentrations as lowas 6 mg/L.Behavior in Air: Sulfuric acid is not combustible, but many reactions may cause fire andexplosion and produce fumes in the air.Behavior in Water: Concentrated sulfuric acid reacts violently with water and producesheat.

35.3.4 Emergency Response–Human Health

Symptoms:Local: Conjunctivitis, corneal necrosis, dermatitis, skin burns, ulceration, fainting. Maylead to pulmonary edema, nausea, and vomiting.Respiratory: Irritation of the nose and throat, coughing, sneezing, laryngeal edema,bronchitis, pneumonitis, and pulmonary edema.Gastrointestinal: Dental erosion, shock, anuria; burning in the mouth, throat, and ab-domen; nausea, vomiting of blood and eroded tissue; perforation of gastrointestinaltract; and albumin, blood, and casts in urine.

Treatment:Inhalation:

Move victim to fresh air.If not breathing, give artificial respiration.


If breathing is difficult, give oxygen.During transportation:

Continue giving oxygen by 40% venturi mask.Observe vital signs.

In emergency room:Check arterial blood gas.Perform a chest X ray.Observe for pulmonary edema and bronchospasms.

Skin:Wash and flush with water immediately.Remove clothing.Shower thoroughly.During transportation:

Cover affected areas with sterile wet dressings immediately.In emergency room:

Treat as burn.Eyes:

Rinse well with large quantities of water for 15 minutes.Hold eyelids open while washing.During transportation:

Continue eye rinsing.In emergency room:

Continue eye rinsing (use Mediflow lens if available).Determine nature and extent of corneal damage.Notify an ophthalmologist.

Ingestion:Do not induce vomiting.During transportation:

Keep victim comfortable in an upright position.Support circulation.

In emergency room:Do not lavage.Treat as acid ingestion.

35.3.5 Spill Control

Wear self-contained breathing apparatus and full protective clothing for all emergency mea-sures involving sulfuric acid.

Leaks: Keep the acid away from water sources and sewers. Build dikes to contain flowas necessary. Neutralize spilled material with agricultural lime (CaO), crushed limestone(CaCO3), soda ash, or sodium bicarbonate. Keep material out of water sources and show-ers and spray large liquid spills with vapor-smothering foams.Fires: Sulfuric acid does not burn by itself. Use a dry chemical to smother small firesinvolving combustibles. Use water in flooding quantities as fog to cope with large fires.Cool affected containers with flooding quantities of water. Apply water from as far awayas possible.Spills: Wear appropriate chemical protective gloves, boots, and goggles. Avoid contactwith contaminated material. Evacuate spill site and restrict access. Issue warning: ‘‘Cor-rosive, Poison.’’ Notify manufacturer and relevant authorities. Contain spill if it is safe todo so. Avoid contact with liquid or vapor. Stay upwind. Vapor cloud collects in low-lying


areas. Keep contaminated water from entering sewers or watercourses. For small liquidspills, neutralize with lime. For large liquid spills, contain spill as much as possible.Neutralize spilled material with crushed limestone, soda ash, or lime.Land spill: Dig a pit, pond, lagoon, or holding area to contain the acid. Dike surfaceflow using soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liquidwith fly ash or cement powder. Neutralize with agricultural lime (CaO), crushed limestone(CaCO3), or sodium bicarbonate (NaHCO3).Air spill: Apply water spray or mist to knock down vapors. Liquid produced is corrosiveand toxic; it should be diked and neutralized.Water spill: Neutralize with agricultural lime (CaO), crushed limestone (CaCO3), orsodium bicarbonate (NaHCO3).

Immediate Concerns

Hazard: Extremely corrosive. Rapidly destroys human tissues on contact. Causes se-vere burns. Sharp, penetrating odor. May react with other chemicals, causing fires andexplosions. Fumes are very toxic. Powerful oxidizer. May react violently with water.May exhibit violent chemical changes at elevated temperatures and pressures.

Humans: Corrosive to skin, eyes, and respiratory system. Will cause burns. Toxic byall routes, causing severe damage to tissues. Death may result.

Environment: Harmful to aquatic life and the environment.

Protection: Complete self-contained breathing apparatus recommended with facemask, suit, boots, and gloves (rubber, neoprene, or plasticized PVC).

35.3.6 Guidelines

The following are some emergency response guidelines provided by the American IndustrialHygiene Association (AIHA) for use during large releases of sulfuric acid (AIHA, 1988).

ERPG-3: 30 mg/m3 (as sulfuric acid mist): The maximum airborne concentration belowwhich it is believed that nearly all individuals could be exposed for up to one hour withoutexperiencing or developing life-threatening health effects.ERPG-2: 10 mg/m3 (as sulfuric acid mist): The maximum airborne concentration belowwhich it is believed that nearly all individuals could be exposed for up to one hour withoutexperiencing or developing irreversible or other serious health effects or symptoms thatcould impair an individual’s ability to take protective action.ERPG-1: 2 mg/m3 (as sulfuric acid mist): The maximum airborne concentration belowwhich it is believed that nearly all individuals could be exposed for up to one hour withoutexperiencing other than mild, transient adverse health effects or without perceiving aclearly defined objectionable odor.

Threshold Limit Values

The American Conference of Governmental Industrial Hygienists (ACGIH) has deter-mined the threshold limit values for TWA(time-weighted average) to be 1 mg/m3 and STEL(short-term exposure limit) to be 3 mg/m3. The ACGIH also recommends a TLV of 1 mg/m3 for sulfuric acid to prevent pulmonary irritation and injury to the teeth.


The Occupational Safety and Health Administration (OSHA) permissible exposure limit(PEL) is 1 mg/m3. The National Institute for Occupational Safety and Health (NIOSH)recommended exposure limit (REL) is 1 mg/m3 (10-hr TWA).

35.4 INDUSTRIAL ASPECTS AND PRODUCTION IN THE UNITEDSTATES, CANADA, AND WORLDWIDE

35.4.1 Manufacture of Sulfuric Acid

Until the late 1800s, sulfuric acid was produced mainly by the lead chamber process, whichuses nitrogen oxides as homogenous catalysts for the sulfur dioxide oxidation step. Thefeedstocks were sulfur, iron pyrites, nonferrous pyrites, hydrogen sulfide, and spent sulfuricacid. Nowadays, approximately 99% of all production is by the contact process. Sulfuricacid is also manufactured to prevent the substantial quantities of waste sulfur dioxide pro-duced in metallurgical processes, such as the smelting of non-ferrous metals like nickel andcopper and iron production from pyrites, from entering the environment. Sulfur dioxideproduced during roasting of sulfide ores is sometimes referred to as roaster gas. Hydrogensulfide gas is another useful raw material for the manufacture of sulfuric acid. The followingare the steps involved in the production of SO2 for the contact process.

1. As the sulfide ores (pyrites) are roasted, the roaster gas and the metal oxides producedare separated from each other in cyclones.

3 Fe S � 38 O 2 Fe O � 24 SO (35.1)7 8 2 3 4 2

Ni S � 2 O → 3 Ni � 2 SO (35.2)3 2 2 2

2. The roaster gas is mixed with additional air to complete the combustion of all volatilizedproducts.

3. Any remaining metal oxides in the roaster gas are removed by cooling and contactingwith sulfuric acid solution.

4. The roaster gas is then passed through a further stage of washing and drying, followedby a wet precipitation stage.

5. Following the primary converter, the process gas passes through an interpass absorptiontower. This tower removes SO3 from the process gas to provide improved equilibriumconditions for further oxidation of SO2 to SO3 in a second converter. SO3 produced inthe second converter is absorbed in the final absorber.

6. The roaster gas is catalytically oxidized to sulfur trioxide in a fixed bed converter whichoperates adiabatically with each catalyst pass.

⇀2SO � O 2SO (35.3)↽2 2 3

7. The gas is now cooled and allowed to flow into the packed towers, where it is absorbed.The production of fuming sulfuric acid (oleum), however, requires sulfur trioxide absorp-tion in special absorption towers irrigated with oleum. The reaction is exothermic.

SO � H O → H SO (35.4)3 2 2 4


35.4.2 Manufacturers in Canada and the United States

Canadian and American manufacturers of sulfuric acid are listed here. It should be addedthat some of these plants have been mothballed and others may have changed hands orclosed.

Canadian manufacturers Plant location

Sherritt Fort Saskatchewan Redwater, ABAlcan Smelters and Chemicals Jonquiere, QCAllied Chemical Canada Valleyfield, QCBorder Chemical Transcona, MBBrunswick Mining and Smelting Belledune, NBCameco Key Lake and Rabbit Lake, SKCanadian Electrolytic Zinc Valleyfield, QCCogema Resources McClean Lake, SKCominco Trail and Kimberly, BCFalconbridge Sudbury, ONGaspe Copper Mines Murdochville, QCHudson Bay Mining Flin Flon, MBICI Canada Beloeil, QCInco Coppercliff, ONInternational Minerals and Chemicals Port Maitland, ONKidd Creek Mines Kidd Creek, ONKronos Canada Varennes, QCLever Toronto, ONMarsulex Fort Saskatchewan, ABNoranda Rouyn-Noranda, QCSolv-Ex Fort McMurray, ABSulco Chemicals Elmira, ONSulconam Montreal East, QCWestcoast Energy Prince George, BCWestern Co-operative Fertilizers Calgary and Medicine Hat, AB

American manufacturers Plant location

Akzo Chemicals Le Moyne, ALAmoco Chemical Texas City, TXArcadian Geismar, LAAsarco Three locationsBig River Zinc Sauget, ILBoliden Intertrade Copperhill, TXCargill Fertilizer Bartow and Riverview, FLCF Industries Plant City, FLChevron Chemical El Segundo, CA, and Honolulu, HICitgo Petroleum Lake Charles, LAClimax Molybdenum Fort Madison, IACoulton Chemical Cairo and Oregon, OHCyprus Minerals Claypool, AZCytec Fortier, LADoe Run Herculaneum, MODupont Chemicals Six locationsEl Dorado Chemical El Dorado, ARFarmland Pierce, FLGeneral Chemical Three locations


American manufacturers Plant location

IMC-Agro Five locationsJersey Miniere Zinc Clarkesville, TNJ R Simplot Lathrop, CA, and Pocatello, IDKemira Savannah, GAKennecott Salt Lake City, UTKoch Sulfur Products Five locationsMagma Copper San Manuel, AZMarsulex Sayreville, NJMobil Mining and Minerals Pasadena, TXNu-West Conda, IDOlin Hunt Speciality Products Beaumont, TX, and Shreveport, LAPCS Phosphates Aurora, NC, and White Springs, FLPeridot Chemicals Augusta, GA, and Newark, NJPhelps Dodge Refining Three locationsPublic Service Co of New Mexico Waterflow, NMPVS Chemicals Chicago, IL and Buffalo, NYRhone-Poulenc Basic Chemicals Six locationsRohm and Haas Deer Park, TXSFI Phosphates Rock Springs, WYSouthern States Savannah, GATampa Electric Tampa, FLTosco Refining Martinez, CAUnocal Chemicals Wilmington, CAU.S. Agri-Chemicals Fort Meade, FLU.S. Army Radford, VAZinc Corp. of America Bartlesville, OK and Monaca, PA

The major buyers in Canada are Abitibi-Consolidated, Alcan Smelters and Chemicals,Canadian Copper Refiners, Canadian Forest Products, Domtar, E.B. Eddy Forest Products,Explosive Technologies, Imperial Oil, Kimberly-Clark of Canada, MacMillan Bloedel, Proc-ter and Gamble, Shell Canada, Scott Maritimes, and Weyerhaeuser Canada.

The major buyers in the United States are AGP Refineries, Agrium, Air Products andChemicals, Alabama River Pulp, Boise Cascade, Champion International, Consolidated Pa-pers, Federal Paper Board, Georgia Pacific, Glatfelter, International Paper, Procter and Gam-ble, and Warren and Weyerhaeuser Paper.

35.4.3 Production and Transportation

In 1996, the total nameplate capacity for sulfuric acid in Canada was 5,681 kilotons and inthe United States it was 36,306 kilotons. In 1993, the total global production of sulfuric acidwas close to 135.3 megatons. Some growth is expected in the Middle East and North Africa.In Canada and the United States, sulfuric acid is transported primarily by rail and truck.Long-distance transport of sulfuric acid from smelters in remote locations makes freightcosts extremely high.

35.5 CHEMISTRY

Some of the chemical reactions often encountered during sulfuric acid spills are discussedhere. One common element in all these reactions is the large quantity of heat that is given


off. As these reactions are typically exothermic, some caution is required during emergencyresponse operations and spill mitigation.

35.5.1 Neutralization

Like most strong mineral acids, sulfuric acid will react with bases to form salt and water.Therefore, substances such as slaked lime or sodium hydroxide are often added to sulfuricacid spills.

H SO � 2 NaOH → Na SO � 2 H O (35.5)2 4 2 4 2

H SO � Ca(OH) → CaSO � 2H O (35.6)2 4 2 4 2

35.5.2 Reaction with Water and Hygroscopicity

Concentrated sulfuric acid is a strong dehydrating agent with an enormous affinity for water.It will extract water and elements of water from most materials, e.g., organic and inorganicwith evolution of heat. Sometimes enough heat is generated to ignite surrounding combus-tible materials or vapor.

H SO � H O → H SO � H O (35.7)2 4 2 2 4 2

(C H O ) � H SO → 6C � H SO � 5H O (35.8)6 10 5 X 2 4 2 4 2

35.5.3 Fire and Intense Heat

Sulfuric acid itself is not combustible, but under certain conditions, it can produce enoughheat when reacting with other substances to ignite or decompose.

4 H SO → 4 H O � 2 SO � 2 SO � O (35.9)2 4 2 2 3 2

35.5.4 Reaction with Metals

Under certain conditions, sulfuric acid can react with many metals to produce salt andflammable, explosive hydrogen gas. It will also corrode many materials to form innocuoussubstances. It will react with many sulfides, oxides, and carbonates.

2 Al � 3 H SO → Al (SO ) � 3 H (35.10)2 4 2 4 3 2

2 Fe � 3 H SO → Fe (SO ) � 3 H (35.11)2 4 2 4 3 2

FeS � H SO → FeSO � H S (35.12)2 4 4 2

35.5.5 Oxidation

Concentrated sulfuric acid is a strong oxidizing agent and can oxidize carbon, nonmetallicelements, and many metals. These reactions generally occur when the acid is in high con-centrations and at high temperatures. The potential hazard of these reactions is due to theformation of sulfur dioxide, a toxic gas.


C � 2 H SO → CO � 2 SO � 2 H O (35.13)2 4 2 2 2

Pb � 3 H SO → Pb(HSO ) � SO � 2 H O (35.14)2 4 4 2 2 2

Cu � 2 H SO → CuSO � SO � 2 H O (35.15)2 4 4 2 2

35.5.6 Hazardous Reactions

Sulfuric acid will undergo many double-displacement reactions to produce new substancesthat may be hazardous. These substances should therefore be stored at distant locations.

2 NaBr � 2 H SO → Br � SO � NaSO � 2 H O (35.16)2 4 2 2 4 2

3 NaClO � 3 H SO → 3 NaHSO � HClO � 2 ClO � H O (35.17)3 2 4 4 4 2 2

2 HClO → Cl O � H O violent explosion (35.18)4 2 7 2

8 HI � 3 H SO → H S � 4 I � 4 H O (35.19)2 4 2 2 2

35.6 BEHAVIOR

Sulfuric acid is a heavy, viscous, water-soluble, and very corrosive liquid. Although sulfuricacid is not a volatile substance, fuming sulfuric acid (referred to as oleum) is. Since it doesnot evaporate extensively, it is hard to detect by smell. Sulfate aerosols and mist may formin the atmosphere.

35.6.1 Terrestrial Fate

When spilled on land, sulfuric acid will settle for a few minutes before flowing away as itfinds the lowest levels. It will sorb to the soil and char any vegetation with which it comesin contact. Because of its high viscosity, concentrated amounts will not rapidly leach intothe soil unless it rains or other precipitation occurs. The process of soil acidification involvesreplacing exchangeable base cations such as calcium and magnesium with protons and alu-minum ions. In other words, removing bases and mobilizing aluminum are the key processes.As sulfuric acid penetrates the soil, some of it will be neutralized by bases and carbonates,some will react with silicates and organic materials, some will exchange with metal cations,and the rest may leach into groundwater.

35.6.2 Aquatic Fate

If spilled into water, sulfuric acid will mix convectively and dissolve in the water columnas it sinks. Vigorous turbulent mixing will occur as the sulfuric acid front advances, resultingin entrainment. As the entrainment grows, the density differences will become smaller. Twokinds of acid-spill scenarios can occur: (1) those in which no appreciable amount of acidaerosols are produced, and (2) those in which acid aerosols form and provide the majorhazard.

In both cases, large amounts of heat are liberated at the early stages of the spill. Examplesof the first kind of spill are a capsized barge with all the hatches wide open and a gradualleak from a ship in a collision underwater. The second kind involves a spill of fuming sulfuricacid or oleum over water surfaces and shallow surface water. The heat released as a result


TABLE 35.2 Human Responses to Sulfuric Acid Mist

Concentrations (mg/m3) Response

0.5 to 2.0 Barely noticeable irritation3.0 to 4.0 Coughing, easily noticeable6.0 to 8.0 Decidedly unpleasant, marked

alterations in respiration

of dilution provides latent heat, and the heat of vaporization produces acid mist of sulfurtrioxide and water to form sulfuric acid. Sulfuric acid will also react with any bases andorganic matter in the water. It has been shown that very low pH is extremely toxic to fishand aquatic organisms.

35.6.3 Study of a Sulfuric Acid Spill near Springhill, Nova Scotia

On December 13, 1978, a railway tank car of concentrated sulfuric acid (93%) was spilledas a result of a train derailment about 10 km northwest of the town of Springhill, NovaScotia. The spill caused visible damage to vegetation over a limited area. In the fall of 1985,seven growing seasons after the spill, Environment Canada contracted MacLaren PlansearchLimited, in association with P. Lane and Associates Limited, to undertake a study to docu-ment the effects of the spill and make recommendations on appropriate response measuresfor future spills of sulfuric acid (Environment Canada, 1986). Some Environment Canadascientists were also involved in the research project. This spill and the results of the studyare discussed in Section 35.8.2.

35.7 HUMAN AND ENVIRONMENTAL TOXICITY

35.7.1 Effects on Humans

The most common types of injuries to people during spills of concentrated sulfuric acid areburns as a result of direct contact with this acid. These burns often cause marked scarringof the skin. The concentrated form of sulfuric acid destroys organic matter as a result of itssevere dehydrating action. It is also a severe irritant to the eyes, respiratory tract, and skin.The respiratory system and teeth are usually damaged as a result of chronic exposure to theacid aerosols and mists.

Accidental exposure to liquid fuming sulfuric acid can result in skin burns as well aspulmonary edema from inhalation. Pulmonary fibrosis, residual bronchitis, and pulmonaryemphysema have also been reported. A single overexposure to sulfuric acid may lead toacute laryngeal, tracheobronchial, and pulmonary edema. Concentrations of around 5 mg/m3 have been found quite objectionable, often causing coughs and respiratory dysfunctions.The data in Table 35.2 summarize human responses to various levels of concentration ofsulfuric acid mist.

Investigations of respiratory effects of sulfuric acid during acute exposures, as in somespill cases, have had mixed results because there are many factors that influence its toxicity.These factors include particle size of the mist, humidity, presence of particulate, synergisticand protective agents, and preexisting conditions of victims (Amdur, 1989; Amdur and Chen,1989; Linn et al., 1989; Lippmann, 1989; and Schlesinger et al., 1984). Bronchospasm inasthmatics has been shown to be a major concern. These effects are caused mainly by


TABLE 35.3 Effects of Sulfuric Acid on Animals

Concentration(�g /m3), time Species Effects

100, 1 hour Guinea pig Pulmonary resistance increased 47%, pulmonarycompliance decreased 27%.

500, 1 hour Dog Slight increases in tracheal mucociliary transportvelocities immediately and one day afterexposure. One week later clearance wassignificantly decreased.

510, 1 hour Guinea pig Pulmonary resistance increased 60%. Pulmonarycompliance decreased 33%.

1,000, 1 hour Guinea pig Pulmonary resistance increased 78%. Pulmonarycompliance decreased 40%.

190 and 1,400, no time Donkey Bronchial mucociliary clearance was slowed.1,000, 1 hour Dog Depression in tracheal mucociliary transport rate

persisted one week after exposure.

inhalation of the acid aerosols deposited on the surface of the respiratory tracts. The smallestaerosols (less than10 �m) often cause the greatest alteration in pulmonary function because they can penetratefarther into the alveoli, whereas the larger particles are deposited in the upper respiratorytract. Increase in airway resistance at high acid concentrations has been demonstrated byseveral authors. Presence of ammonia in expired air has been reported to afford some pro-tection in humans. Synergism has been demonstrated when sulfuric acid is deposited on zincoxide dusts in the presence of sulfur dioxide, and also when combined with nitrogen dioxideor sulfur dioxide, ozone, metallic aerosols, and sulfuric acid.

Chronic exposure of the teeth to the corrosive action of sulfuric acid as in battery acidworkers has resulted in etching or total loss of teeth substance. A number of studies havealso shown some association between chronic exposure to sulfuric acid and laryngeal cancer(U.S. Department of Health, Education and Welfare, 1974). For example, a 13-fold excessrisk of laryngeal cancer was found among chemical refinery workers with the highest ex-posure, and a 4-fold risk was found for those moderately exposed, as opposed to very lowexposure. Repeated exposures to sulfuric acid mists have been reported to cause dermatitis,stomatitis, conjunctivitis, and tracheobronchitis.

35.7.2 Animals

A considerable body of evidence exists on the sensitivity of laboratory animals to sulfuricacid. As discussed in Section 35.7.1, inhalation of sulfuric acid causes changes in pulmonaryflow resistance, which are sometimes irreversible. These changes could be seen as the firststage of bronchitis. The smaller the particles (�2 �m), the more damage is done. The resultsof some animal studies are shown in Table 35.3.

35.7.3 Aquatic Species

The main cause of death of species in acid lakes is the excessive loss of sodium ions, whichcannot be rapidly replaced by active transport. The disruption of sodium/potassium pumpmechanism has been attributed to the presence of high concentrations of hydrogen ions.


TABLE 35.4 Effects of Acidity on Aquatic Organisms

pH Effects

6 Crustaceans, molluscs, etc. disappear; white moss increases.5.8 Salmon, char, trout, and roach die. Sensitive insects, phytoplankton,

and zooplankton die.5.5 Whitefish and grayling die.5 Perch and pike die.4.5 Eels and brook trout die.

TABLE 35.5 Effects of Acid Precipitation on Plants

pH Plant Effects

2.5 Bean Foliar aberrations, decrease in growth3.1 Yellow birch Foliar lesions, decrease in growth3.1 Bean, sunflower Foliar lesions3.4 Hybrid poplar Foliar lesions3.4 Sunflower Foliar lesions4.04 Bean Reduction in dry weight

In 1975, sulfuric acid was added to an experimental lake in Canada, causing the pH inthe lake to drop from 6.8 to 5, which killed many fish species. Shrimp and minnows diedat about pH 5.8, followed by the young trout. At pH 5.6, crayfish began to die as theirexoskeletons lost their calcium and became infested with parasites. The sensitivities ofaquatic organisms to the lowering of pH based on studies in Scandinavian lakes are sum-marized in Table 35.4.

35.7.4 Plants

Direct contact of concentrated sulfuric acid with plants will result in perforation of the planttissue and the plant may subsequently die. The most common response of plants to acidicprecipitation is low growth and the formation of foliar lesions or areas of dead tissue on theupper surface of the leaves. Necrotic spotting of the epidermis of the leaves after exposureto sulfuric acid mist has been reported in previous investigations. The effects of acid pre-cipitation on plants are shown in Table 35.5.

35.8 SURVEY OF PAST SPILLS, LESSONS LEARNED, ANDCOUNTERMEASURES APPLIED

Sulfuric acid is the most frequently spilled high-volume hazardous chemical in industry.Unlike spills of other chemicals, some spills are large, especially those that involve rail andship transport. Spills from pipes, bottles, and cylinders are often small. While very few deathshave been reported as a result of these spills, respiratory distress is common.


35.8.1 Sulfuric Acid Spill at a CPR Train Derailment Near MacTier,Parry Sound, Ontario

On February 12, 1984, 14 railcars were fully derailed and another jumped the tracks, spillingsulfuric acid into Beers Lake, 29 km south of Parry Sound in Ontario. Each car contained93 tons of sulfuric acid. Three cars went through the ice, 9 cars were on the bank leadingto the lake, and 1 straddled the tracks. Four cars were leaking from the dome and 1 lost halfits contents

On the night of the spill, a pH reading of 6.5 was measured at the outlet of the lake. Thenext day, tests were taken across the lake and down the center and pH levels ranged from5.0 to 6.0, with one location at 4.5. Officials at the scene believed that most of the acidremained on the shore and in the water nearest the accident. Emergency crews workedthrough the night to contain the spill. One outlet was blocked with sandbags to prevent anyflow of acidic water. Three cars were offloaded during the night. The Canadian TransportCommission investigated a broken wheel as a possible cause of the derailment. Samplingand pH measurements continued as officials from the Ontario Ministry of the Environmentmonitored the spill. Work crews from the Canadian Pacific Railways (CPR) were dispatchedand 15 cars of limestone were sent from Toronto and two truckloads from Sudbury toneutralize the acid spill.

35.8.2 Sulfuric Acid Spill Near Springhill, Nova Scotia

On December 13, 1978, an eastbound CN freight train travelling at approximately 40 mph(64 km/h) derailed close to Springhill, Nova Scotia. A total of 51 cars were derailed. Onerailway tank car containing concentrated sulfuric acid (93%) ruptured and almost its entirecontents spilled. The acid pooled in a swale parallel to the south side of the tracks andflowed downslope along three distinct paths (one major, two minor). Most of the spilled acidflowed into an underground pit or cavity of unknown origin. Because of the highly fracturednature of the bedrock in the area, most of the acid that reached the pit quickly probablyfound its way into the groundwater, although no adverse effects on groundwater were re-ported.

Overland flow of the acid was fairly restricted. Although the spill occurred at the top ofa slope, eyewitnesses from Environment Canada (R. Simmons, L. Tripp) indicated that thethree rivulets of acid flowed only partway down the slope. No acid reached the ditch on thenorth side of the highway at the bottom of the slope. The following factors may havecontributed to this:

1. The amount of acid flowing overland was greatly reduced because most of it flowed intothe underground cavity.

2. The surface materials on the slope were highly permeable.3. Although it was early winter and the ground was lightly snow-covered, the ground was

not yet frozen. This was confirmed by members of the spill response team, who indicatedthere was no frost in the ground when an emergency road was bulldozed to the site.

The Environment Canada report on the spill indicated that a CN employee and a localresident were injured as a result of stepping in a pool of acid (Environment Canada, 1986).

After the derailment, the priority was to restore service on the mainline. No action wastaken to neutralize the spilled acid until a truckload of sodium hydroxide solution arrivedon the site on December 14, 25 hours after the spill occurred. By the time the truckload ofsodium hydroxide was pulled up to the trackside the following day, almost two days hadpassed since the spill. Neutralization was done selectively where pockets of acid could bereached. Sodium hydroxide was allowed to percolate through the new roadbed material to


neutralize the acid underneath. Sgnificant amounts of sodium hydroxide were pumped intothe cavity where much of the acid had flowed. (A solid block of sodium sulfate, the productof neutralizing sulfuric acid with sodium hydroxide, remains in the pit to this day.)

The top of the slope where the spill occurred was severely impacted by physical distur-bance associated with response to the spill. All of the natural vegetation was bulldozed andthe site covered with up to 90 cm of sandy fill. Much of this fill remained almost barren ofvegetation, which is the major long-term disturbance associated with the spill.

The direct effects of the spill itself are relatively subdued after seven growing seasons.The ground vegetation in acidic areas is superficially indistinguishable from unaffected areas.Shrubs are reinvading areas where acid-induced shrub mortality was high. The main signsof the spill are the standing remains of dead shrubs. It is surprising that even after sevenyears all the spilled acid has not leached through. This clearly shows that the hydrogen ionsare held in place by more than simple adsorption forces. Some effects on exchangeable soilminerals were also studied.

35.8.3 Sulfuric Acid Leak

In October, 1993, a 2.5-cm transfer line suddenly failed as workers were transferring sulfuricacid from a 3,785-L storage tank to a 378-L day tank (Loss Prevention, 1993). The leakcaused an 18-m spray from where the leak occurred. A worker was sprayed by the acid mist,which penetrated his clothing and caused second-degree burns on his back. The victim waswashed down in a shower and later taken to a medical facility for treatment.

The bulk storage tank, which contained a 93% sulfuric acid solution, was connected totwo tanks, the day tank and an acid regeneration tank (also called the dilute tank), by 2.5-cm carbon steel lines. The valve in the line connecting the bulk storage tank and the dilutetank was located near the dilute tank. The acid spray was caused by a failure in the linewhere it was connected to the valve. The procedure for transferring acid from the bulk tankto the day tank required that the valve at the dilute tank be closed and a transfer pump beused to facilitate the transfer of acid from the bulk tank to the day tank. When the accidentoccurred, the valve at the dilute tank was closed and the transfer pump had been started.The pump built up pressure in the pipe, causing the acid to spray out.

The failed line was constructed of carbon steel and appeared to be a Schedule 40 pipe,although the engineering drawings specified use of Schedule 160 pipe, which is about twiceas thick. In addition, it was known that the flow of acid through the line normally reducesthe thickness of the pipe wall by about 5 �m per year. The section of the line that failedwas approximately 10 years old. As soon as the leak was discovered and the transfer pumpshut down, the area was barricaded and thoroughly washed. All piping was subsequentlyinspected using nondestructive evaluation (NDE) techniques, and pipes of insufficient thick-ness were replaced.

Lessons Learned

The following lessons were learned from this incident:

1. When system components are replaced or repaired, all engineering documents must bechecked to ensure that the correct materials are used.

2. A preventative maintenance program, including a replacement schedule, must be in place.Management must ensure that all hazardous materials and processes are identified andthat procedures are developed and implemented to ensure safety.

3. Implementation of relevant standards related to mechanical integrity, procedures, andtraining would have prevented the use of incorrect schedule piping.


35.8.4 Sulfuric Acid Spill in Richmond, California

In July 1993, 20 to 50 tons of fuming sulfuric acid spilled at the General Chemical Corp.plant in Richmond, California, a major industrial center near San Francisco. The releaseoccurred when oleum was being loaded into a nonfuming acid railroad tank car that containedonly a rupture disk. The tank car was overheated and this rupture disk blew. The resultingcloud of sulfuric acid drifted northeast with prevailing winds over a number of populatedareas. More than 3,000 people subsequently sought medical attention for burning eyes,coughing, headaches, and nausea. Almost all were treated and released on the day of thespill. By the day after the release, another 5,000 people had sought medical attention. Thespill forced the closure of five freeways in the region as well as some Bay Area RapidTransit System stations. Health officials stated that most of the people affected would sufferno long-term effects from the exposure and that environmental effects would be minimal.

Lesson Learned

Again, a sound preventative maintenance program is crucial to eliminate such accidentalspills.

35.9 CONCLUSIONS

Sulfuric acid is an important substance that is widely used in industry. The effects of sulfuricacid spills are very localized, and evidence suggests that sulfuric acid and oleum do notconstitute a serious threat to the Canadian public at large.

35.10 REFERENCES

Amdur, M. O. 1989. ‘‘Sulfuric Acid: The Animals Tried to Tell Us,’’ Applied Industrial Hygiene, vol.4, pp. 189–197.

Amdur, M. O., and L. C. Chen. 1989. ‘‘Furnace Generated Acid Aerosols: Speciation and PulmonaryEffects,’’ Environmental Health Perspectives, vol. 79: pp. 147–150.

American Industrial Hygiene Association (AIHA). 1988. Emergency Response Planning Guidelines,AIHA, Fairfax, VA.

Bailar, J. C., H. J. Emeleus, R. Nyholm, and A. F. Trotman-Dickenson, eds. 1975. ‘‘Halides,’’ in Com-prehensive lnorganic Chemistry, Pergamon Press, New York, NY, pp. 1124–1280.

Budavari, S. 1989. The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals, 11th ed.Merck & Co., Rahway, NJ.

Camford Information Services, Inc. (CIS). 1997. ‘‘Sulfuric Acid,’’ in CPI Product Profiles, CPI, Scar-borough, ON.

Duecker, W. W., and J. R. West, eds. 1959. The Manufacture of Sulfuric Acid, Robert E. Krieger,Huntington, NY, pp. 1–134.

Environment Canada. 1986. Follow-up Study of Sulfuric Acid Spill Near Springhill, Nova Scotia.Environment Canada. 2000. National Air Pollution Surveillance (NAPS) Network—Annual Summary for1998, Report EPS 7/AP/31, Environmental Protection Service, Ottawa, ON.

Fingas, M., N. Laroche, G. Sergy, B. Mansfield, G. Cloutier, and P. Mazerolle. 1991. ‘‘A New ChemicalSpill Priority List,’’ in Proceedings of the 8th Technical Seminar on Chemical Spills, EnvironmentCanada, Ottawa, ON.


Inco Limited. 1985. Sulfur Dioxide Abatement Project, Final Report-December 1988, Sudbury SmelterComplex, SO2 Emission Control Regulation 660 /85, December 12.

Kirk-Othmer Encyclopedia of Chemical Technology. 1983. 3rd ed., vol. 22, Wiley-Interscience, NewYork, NY.

Linn, W. S., E. L. Avol, K. R. Anderson, D. A. Shamoo, R. C. Peng, and J. D. Hackney. 1989. ‘‘Effectof Droplet Size on Respiratory Responses to Inhaled Sulfuric Acid in Normal and Asthmatic Volun-teers,’’ American Review of Respiratory Disease, vol. 140, pp. 161–166.

Lippmann, M. 1989. ‘‘Background on Health Effects of Acid Aerosols,’’ Environmental Health Per-spectives, vol. 79, pp. 3–6.

Loss Prevention. 1993. ‘‘Acid Line Breaks—Worker Burns,’’ p. 4.Muller, T. L. 1997. ‘‘Sulfuric Acid and Sulfur Trioxide,’’ in Encyclopedia of Chemical Technology, 4thed., ed. M. Howe-Grant, vol. 23, John Wiley & Sons, New York, NY, pp. 363-407.

RRETCS On-Line. 1999. Registry of Toxic Effects of Chemical Substances, Department of Health andHuman Services, Centers for Disease Control, National Institute for Occupational Safety and Health,Washington, DC.

Schlesinger, R. B., L.-C. Chen, and K. E. Driscoll. 1984. ‘‘Exposure Response Relationship of BronchialMucociliary Clearance in Rabbits, following Acute Inhalations of Sulfuric Acid Mist,’’ ToxicologyLetters, vol. 22, pp. 249–254.

U.S. Department of Health, Education and Welfare. 1974. Occupational Exposure to Sulfuric Acid,Criteria for a Recommended Standard.

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