# Guide 117: Gases - Toxic - Flammable (Extreme Hazard)

- **operation:** document
- **citation:** ERG 2024 Guide 117
- **title:** Guide 117: Gases - Toxic - Flammable (Extreme Hazard)
- **source type:** guidance
- **agency:** U.S. DOT / Transport Canada / SICT
- **status:** guidance
- **official:** true
- **published on:** 2024-04-04
- **effective on:** Not available
- **summary:** ERG2024 response Guide 117: Gases - Toxic - Flammable (Extreme Hazard).
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- **app url:** https://regulus.evalyn.ai/document/phmsa-erg-2024-guide-117
- **source url:** https://www.phmsa.dot.gov/erg/guide?number=117
**body:**

GUIDE
117
Gases - Toxic - Flammable
(Extreme Hazard)
POTENTIAL HAZARDS
HEALTH
•
TOXIC; Extremely Hazardous.
•
May be fatal if inhaled or absorbed through skin.
•
Initial odor may be irritating or foul and may deaden your sense of smell.
•
Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
•
Fire will produce irritating, corrosive and/or toxic gases.
•
Runoff from fire control or dilution water may cause environmental contamination.
FIRE OR EXPLOSION
•
These materials are extremely flammable.
•
May form explosive mixtures with air.
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May be ignited by heat, sparks or flames.
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Vapors from liquefied gas are initially heavier than air and spread along ground.
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Vapors may travel to source of ignition and flash back.
•
Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
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Runoff may create fire or explosion hazard.
•
Cylinders exposed to fire may vent and release toxic and flammable gas through pressure relief devices.
•
Containers may explode when heated.
•
Ruptured cylinders may rocket.
•
•
•
•
•
PUBLIC SAFETY
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
not available or no answer, refer to appropriate telephone number listed on the inside back cover.
Keep unauthorized personnel away.
Stay upwind, uphill and/or upstream.
Many gases are heavier than air and will spread along the ground and collect in low or confined areas
(sewers, basements, tanks, etc.).
Ventilate closed spaces before entering, but only if properly trained and equipped.
PROTECTIVE CLOTHING
•
Wear positive pressure self-contained breathing apparatus (SCBA).
•
Wear chemical protective clothing that is specifically recommended by the manufacturer when there is
NO RISK OF FIRE.
•
Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.
EVACUATION
Immediate precautionary measure
•
Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
Spill
•
See Table 1 - Initial Isolation and Protective Action Distances.
Fire
•
If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 1600 meters (1 mile) in all
directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions.
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ERG 2024

Gases - Toxic - Flammable
(Extreme Hazard)
GUIDE
117
EMERGENCY RESPONSE
FIRE
•
DO NOT EXTINGUISH A LEAKING GAS FIRE UNLESS LEAK CAN BE STOPPED.
Small Fire
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Dry chemical, CO2, water spray or regular foam.
Large Fire
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Water spray, fog or regular foam.
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If it can be done safely, move undamaged containers away from the area around the fire.
•
Damaged cylinders should be handled only by specialists.
Fire Involving Tanks
•
Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles.
•
Cool containers with flooding quantities of water until well after fire is out.
•
Do not direct water at source of leak or safety devices; icing may occur.
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Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank.
•
ALWAYS stay away from tanks in direct contact with flames.
SPILL OR LEAK
•
ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.
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All equipment used when handling the product must be grounded.
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Do not touch or walk through spilled material.
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Stop leak if you can do it without risk.
•
Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled
material.
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Do not direct water at spill or source of leak.
•
If possible, turn leaking containers so that gas escapes rather than liquid.
•
Prevent entry into waterways, sewers, basements or confined areas.
•
Isolate area until gas has dispersed.
•
Consider igniting spill or leak to eliminate toxic gas concerns.
FIRST AID
Refer to the “General First Aid” section.
Specific First Aid:
•
In case of contact with liquefied gas, only medical personnel should attempt thawing frosted parts.
•
In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove
clothing if adhering to skin.
In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product.
Please consult the shipping paper and/or the "ERAP" section.
ERG 2024
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