31 hazardous materials: scene safety and control
TRANSCRIPT
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Hazardous Materials: Scene Safety and Control
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Objectives (1 of 4)
• Describe hazardous materials personal protective equipment.
• Identify the purpose, advantages, and limitations of structural firefighting protective clothing, high temperature-protective clothing, chemical-protective clothing, liquid splash-protective clothing, and vapor-protective clothing.
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Objectives (2 of 4)
• Discuss respiratory protection in a hazardous material incident.
• Describe the levels of hazardous materials personal protective equipment.
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Objectives (3 of 4)
• Identify skin-contact hazards encountered at hazardous materials incidents.
• Describe the safety precautions to be observed, including those for heat and cold stress, when approaching and working at hazardous materials incidents.
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Objectives (4 of 4)
• Describe the physical capabilities required and limitations of personnel working in personal protective equipment.
• Describe techniques used to isolate hazard areas and deny entry.
• Describe the importance of the buddy system and back-up personnel.
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Introduction
• Scene control, site management, and personal accountability are critical.
• Safe handling of hazardous materials incident determined in the first five minutes
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Levels of Damage
• Threshold Limit Value/Short-Term Exposure Limit (TLV-STEL)
• Threshold Limit Value/Time Weighted Average (TLV-TWA)
• Threshold Limit Value/Ceiling (TLV-C)• Threshold Limit Value/Skin (TLV-S)• Permissible Exposure Limit (PEL) • Immediately Dangerous to Life and Health
(IDLH)
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TLV-STEL
• Maximum concentration a person can be exposed to in 15-minute intervals, up to four times a day without damage.– Minimum one hour rest between exposures
• Lower the TLV-STEL, the more toxic the substance.
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TLV-TWA
• Maximum concentration a person could be exposed to 8 hours a day, 40 hours a week without damage
• The lower the TLV-TWA, the more toxic the substance.
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TLV-C
• Maximum concentration a person could be exposed to, even for an instant.
• The lower the TLV-C, the more toxic the substance.
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TLV-S
• Indicates that direct or airborne contact could result in a possible and significant exposure by absorption through the skin, mucous membranes, and eyes
• Take appropriate measures to minimize contact with the skin.
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PEL
• Maximum, time-weighted concentration to which 95% of healthy adults can be exposed over a 40-hour workweek without damage– Also called the REL (Recommended
Exposure Level)– Comparable to the TLV-TWA
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IDLH (1 of 3)
• An atmospheric concentration of any toxic, corrosive, or asphyxiant that poses an immediate threat to life or could cause irreversible or delayed adverse health effects
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IDLH (2 of 3)
• Three types of IDLH atmospheres:– Toxic– Flammable– Oxygen-deficient
• IDLH atmospheres require the use of SCBA or equivalent protection.
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IDLH (3 of 3)
• Below IDLH levels, most healthy individuals could escape the atmosphere without respiratory protection without irreversible damage to their health.
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Determining Atmospheric Safety
• Atmospheric monitoring requires specific training and equipment.
• Three types of atmospheres at a hazardous materials incident:– Safe– Unsafe– Dangerous
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Selection of Proper PPE
• Turnout gear will not protect against many hazardous materials.
• PPE is selected based on the specific properties of the products involved.
• The IC should approve the level of PPE to be used on an incident.
• Fire fighters should not use PPE they have not been trained to use.
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Types of PPE
• Clothing and Work Uniforms
• Structural Firefighting Protective Clothing
• High-Temperature Protective Clothing
• Chemical Protective Clothing and Equipment
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Hazardous Materials Protection (1 of 2)
• Clothing and Work Uniforms– Offers no protection from hazardous
materials
• Structural Firefighting Protective Clothing– Offers almost no chemical protection
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• High-Temperature Protective Clothing– Offers protection
from high temperatures only
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Hazardous Materials Protection (2 of 2)
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Chemical Protective Clothingand Equipment (1 of 2)
• Designed to prevent chemicals from coming in contact with the body– Have varying degrees of resistance
• Chemical-resistant materials – Designed to inhibit or resist the passage of
chemicals into and through the material
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Chemical Protective Clothingand Equipment (2 of 2)
• Important Concepts– Penetration– Permeation– Degradation
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Penetration
• Flow or movement of a hazardous chemical through closures, seams, porous materials, pinholes, or other imperfections
• Liquids and solids can penetrate.
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Permeation
• Process by which a hazardous chemical moves through a material at the molecular level
• Implies the chemical going through the material itself, rather than through an opening in the material
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Degradation
• Physical destruction or decomposition of a material due to chemical exposure, general use, or ambient conditions
• Usually evidenced by signs such as charring, shrinking, swelling, color changes, or dissolving
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Garment Construction
• Single-piece– Completely encloses wearer – Known as an encapsulated suit or acid suit
• Multi-piece– Works with the wearer’s respiratory
protection, an attached or detachable hood, gloves, and boots
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Material Used In Construction
• Butyl rubber
• Tyvek®
• Saranex
• PVC
• Vitron
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Liquid Splash-Protective Clothing
• Protects skin and eyes• Does not protect
against gases or vapors• Should not be used for
incidents involving liquids that emit vapors
• May be worn over or under structural firefighting clothing
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Vapor-Protective Clothing
– Must be used when hazardous vapors are present
– Traps heat and perspiration
– Must be used in conjunction with respiratory protection
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Respiratory Protection Devices
• Self-contained breathing apparatus (SCBA)
• Supplied air respirator (SAR)
• Air-purifying respirator (APR)
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SCBA
• Prevents exposure through inhalation or ingestion
• Should be mandatory for fire service personnel
• Fire fighters must know the limitations of SCBA
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SAR
• User is connected to an external air source by a hoseline that connects to the facepiece.
• Useful during extended operations– Decontamination – Clean-up
• Hoseline may restrict movement.
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APRs (1 of 2)
• Filter particulates and contaminants from the air
• Should only be used when:– Type and amount of
contaminants are known
– Atmosphere is not oxygen-deficient
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APRs (2 of 2)
• Limitations:– Filtering cartridges are contaminant-
specific.– Atmosphere must be continuously
monitored.
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Level A Protection
• Fully encapsulating suit
• Highest level of protection– Effective against
vapors, gases, mists, dusts
• Requires SCBA or SAR
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Level B Protection
• Consists of chemical-protective clothing, boots, gloves, and SCBA
• Used when high respiratory protection but less skin protection required
• Type of gloves and boots worn depends on the chemical involved
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Level C Protection
• Standard work clothing plus chemical-protective clothing
• Appropriate when:– Type of airborne
substance is known– Concentration is
measured– Criteria for using an APR
is met– Skin or eye exposure is
unlikely
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Level D Protection
• Lowest level of protection
• Used when:– Atmosphere contains no
known hazard. – Work functions preclude
splashes, immersion, or potential for inhalation.
• Should be used for nuisance contamination only
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Skin Contact Hazards (1 of 4)
• Principal dangers of hazardous materials are toxicity, flammability, and reactivity.
• Hazardous materials can harm the inadequately protected body.
• Assume the worst and leave the largest possible safety margin.
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Skin Contact Hazards (2 of 4)
• Skin can absorb harmful toxins without any sensation to the skin itself.– Do not rely on pain or irritation as a
warning of absorption.
• Some substances are lethal if only a few drops contact the skin.
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Skin Contact Hazards (3 of 4)
• Skin absorption is enhanced by cuts, abrasions, heat, and moisture.
• Absorption rate depends on body part.– Chemicals absorbed through the skin on
the scalp much faster than through the forearm
– Eyes have one of the fastest means of exposure.
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Skin Contact Hazards (4 of 4)
• Corrosives do not have to be absorbed to do damage.– Acids– Have affinity for moisture
• Can burn respiratory tract
– Alkalis• Cause deep burns• Turns tissue to soapy liquid
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Safety Precautions
• Standard safety precautions for firefighting apply to hazardous materials incidents.
• In addition, special attention must be paid to temperature and stress.
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Excessive Heat Disorders
• Fully encapsulating and chemical-protective suits do not “breathe.”– Personnel in such suits are at greater risk
for heat-related emergencies.
• Heat-related emergencies:– Heat Exhaustion– Heat Stroke
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Heat Exhaustion (1 of 2)
• Mild form of shock caused by overheating when the body cannot dissipate heat
• Signs and symptoms include:– Elevated core temperature– Weakness– Profuse sweating– Dizziness
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Heat Exhaustion (2 of 2)
• Emergency Action:– Remove victim from the source of heat– Rehydrate– Provide cooling
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Heat Stroke (1 of 2)
• Life-threatening condition resulting from the total failure of the body’s temperature-regulation capacity
• Signs and symptoms include:– Reduction or cessation of sweating – Body temperature at or above 105ºF – Rapid pulse
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Heat Stroke (2 of 2)
• This is a true medical emergency requiring immediate transport to a medical facility.
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Prevention of Heat-Related Emergencies
• Prehydrate with 8 to16 oz. of water before donning PPE.
• Rehydrate with 16 oz. of water for each SCBA cylinder used.
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Cold-Related Emergencies (1 of 3)
• Two types of cold exposure:– Materials-related
• Liquified gases and cryogenic materials• Gases released under pressure
– Weather-related• Wind speed and temperature
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Cold-Related Emergencies (2 of 3)
• Despite temperature, fire fighters will sweat. – Wet clothing extracts heat from the body
up to 240 times faster than dry clothing. – May lead to hypothermia
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Cold-Related Emergencies (3 of 3)
• Prevention – Wear appropriate, layered clothing. – Warm up in heated shelters or vehicles. – Keep layers next to skin dry.
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Physical Capability Requirements
• Hazardous materials responses are physically and psychologically stressful.
• A health and safety management program is needed to ensure responders are capable of meeting challenges of the work.
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Medical Surveillance Program(1 of 2)
• Part of the health and safety management program.
• Includes:– Fitness for duty determinations– Detection of changes in body systems due
to physical and/or chemical exposures
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Medical Surveillance Program(2 of 2)
• Pre-entry values should be attained within 15 to 20 minutes after leaving environment.
• Treat and transport anyone who does not return to normal values within 20 minutes.
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Response Safety Procedures
• Actions for Awareness-level responders– Isolate and deny entry.– Try to identify products.– Follow the NAERG.– Follow SOPs.– Eliminate possible ignition sources.
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Control Zones (1 of 2)
• Designated areas at a hazardous materials incident based upon safety and the degree of hazard
• Types:– Hot zone– Warm zone– Cold zone
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Control Zones (2 of 2)
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Hot Zone
• Area immediately around the incident site
• Contains personnel and equipment needed to control the release
• Is contaminated
• Access is limited.
• Entries and exits are logged.
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Warm Zone
• Staging area for entering and leaving the hot zone
• Contains an access corridor and a decontamination corridor
• Only essential personnel allowed.• Personnel must be in appropriate PPE.
– Generally one level below what is used in the hot zone
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Cold Zone
• Safe area where special protective clothing is not needed
• Restricted area
• Cold zone operations include:– Personnel staging– Command post– Medical support area
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Isolation Techniques (1 of 2)
• Approach from uphill.
• Resist the urge to rush in.
• Establish a perimeter.
• Ensure perimeter control devices do not impede rapid evacuation.
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Isolation Techniques (2 of 2)
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Buddy System and Back-up Personnel
• Back-up personnel must be ready to respond quickly into the hot zone to rescue any personnel if an emergency occurs.
• Work in teams of two.
• Do not rely solely on radios for communication in the hot zone.
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Summary (1 of 4)
• PPE is product-specific.– No such thing as generic chemical-protective suit– PPE has limitations; fire fighters must know them.
• Four recognized levels of protective clothing– Level A provides the most protection.– Level D provides almost no protection.
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Summary (2 of 4)
• Use of respiratory protection is essential on most hazardous materials incidents
• Be aware of and know how to handle both heat- and cold-related emergencies
• Monitor responder vital signs before, during, and after a hazardous materials incident.
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Summary (3 of 4)
• Resist the urge to rush in.
• Only fire fighters trained to the technician or specialist levels should enter the hot zone.
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Summary (4 of 4)
• Work in teams of two in the hot zone.
• Ensure a back-up team is prepared to enter the hot zone to effect a rescue.
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