6.3 Leaks, Spills, Vapor Hazards & Tank Vehicle Fires

Most of the tank endorsement is about preventing leaks, fires, and rollovers. This section covers what to do when prevention fails. The goal is simple: protect people first, keep ignition sources away, and give trained responders accurate information.

First Priorities

1. Protect people, including yourself. No cargo is worth an injury.
2. Stop the vehicle in a safe place if you can. The manual's fire rules say to park in an open area away from buildings, trees, brush, other vehicles, and anything that might catch fire, and don't pull into a service station.
3. Shut off the engine and ignition sources, and don't smoke.
4. Stop the release only if it is safe, for example by using the remote emergency closure (Section 5.3). Don't walk through spilled product or vapor to reach a valve.
5. Protect the area with flashers and reflective triangles. No flares near a flammable-liquid or flammable-gas tank (49 CFR 392.25).
6. Notify authorities with the exact location, product, and what is happening.
7. Keep people away and wait for responders.

Leaks

The manual is clear that you may not carry liquids or gases in a leaking tank. If you find a leak:

• On the road: pull off safely, away from people, drains, and waterways where possible.
• During a transfer: stop flow with the valves or emergency closure and follow the facility's spill procedures.
• Small drips from a fitting: don't continue the trip. Report it and get it repaired.
• Don't try to plug a pressurized leak or tighten a manhole cover on a tank that may be under pressure.

Using the Emergency Response Guidebook (ERG)

The ERG is the U.S. DOT guide first responders use in the first minutes of a hazmat incident. Many hazmat drivers carry one.

The ID number is on the shipping papers and on the placards or orange panels of many tank vehicles. For hazardous materials, federal rules require the shipping paper to be within your reach while you are at the controls, and in a holder on the inside of the driver's door or on the driver's seat when you are away from the controls (49 CFR 177.817(e)).

Isolation distances for two common tank loads (ERG 2024)

Always look up the actual product. These two guides cover many tanker loads, but not all of them.

Upwind, Uphill, Upstream

The ERG's public safety advice is to stay upwind, uphill, and/or upstream.

• Upwind: keep the wind at your back as you face the scene, so vapors blow away from you.
• Uphill: spilled liquid flows downhill into ditches, drains, and low ground.
• Upstream: product that reaches water travels downstream.

The ERG notes that most flammable liquid vapors are heavier than air. They spread along the ground and collect in low or confined areas such as sewers and basements, and vapors may travel to a source of ignition and flash back. Keep bystanders, running vehicles, and other ignition sources well away from low areas near a spill.

When a Tank Is Exposed to Fire

A tank heated by fire can build pressure and rupture violently. For liquefied gases such as propane, this is the explosion hazard responders call a BLEVE (boiling liquid expanding vapor explosion): the heated shell weakens above the liquid level while pressure rises inside, and the tank can fail and release a fireball and fragments.

ERG guides for tanks in fire tell responders to:

• Always stay away from tanks in direct contact with flames.
• Withdraw immediately if there is a rising sound from venting safety devices or discoloration of the tank.
• Fight fire from maximum distance or use unmanned hose holders or monitor nozzles, and cool containers with flooding quantities of water, which is work for trained firefighters with the right equipment.

For a driver, the right move with a burning tank vehicle is to get away, keep others away, and call for help.

Fighting Small Fires: The Manual's Rules

A driver may be able to put out a small fire, such as a tire or brake fire, before it reaches the cargo. The general driving section says:

• Know how your extinguisher works before you need it.
• Pull off the road to a safe open area and notify emergency services.
• Keep the fire from spreading. With an engine fire, turn off the engine and don't open the hood if you can avoid it.
• Stay as far away as possible, position yourself upwind, and aim at the source or base of the fire, not up in the flames.
• Use the right extinguisher. The B:C type is for electrical fires and burning liquids. The A:B:C type also works on wood, paper, and cloth.
• Don't use water on a gasoline fire; it will spread the flames. Don't use water on an electrical fire.
• A burning tire must be cooled, and lots of water may be required.
• If you're not sure what to use, especially on a hazardous materials fire, wait for firefighters.
• Absence of smoke or flame does not mean the fire cannot restart.

Reporting Hazmat Incidents

Immediate telephone notice (49 CFR 171.15)

The person in physical possession of the hazardous material must call the National Response Center at 800-424-8802 (or 202-267-2675) as soon as practical, but no later than 12 hours after the incident, when, as a direct result of hazardous material:

• A person is killed
• A person is injured and admitted to a hospital
• The general public is evacuated for one hour or more
• A major transportation artery or facility is closed for one hour or more
• An aircraft's flight pattern or routine is altered

Calls are also required for certain radioactive material and infectious substance incidents, a marine pollutant release over 119 gallons of liquid, and any situation the person in possession judges should be reported, such as a continuing danger to life.

Written report (49 CFR 171.16)

A Hazardous Materials Incident Report on DOT Form F 5800.1 is due within 30 days of discovering a reportable incident, including any unintentional release of hazardous material.

Your carrier handles much of the paperwork, but the driver's call and accurate information start the process. Shipping papers also list an emergency response telephone number for the product.

Common Test Traps

• "Upwind or downwind of a spill?" Upwind, uphill, and upstream.
• "Water on a gasoline fire?" No; it spreads the flames.
• "Tank of gasoline on fire: how far to isolate?" At least 1/2 mile in all directions under ERG Guide 128.
• "Warning signs a heated tank may fail?" A rising sound from venting safety devices or discoloration of the tank; withdraw immediately.