Accidents involving alternative fuel vehicles are not inherently more dangerous than accidents involving gasoline or diesel fuel vehicles. However, they do have varying safety considerations first responders need to be aware of to ensure the safety of themselves and others.
The different fuels and fueling systems of alternative fuel vehicles bring unique characteristics to cars and trucks on the road. These include high-voltage electricity, compressed or liquefied gases, and high-pressure tanks. When damaged, alternative fuel vehicles require treatment different than conventional cars and trucks.
An important first step when responding to an accident is to identify the type of fuel the vehicle uses. Most manufacturers place labels on their vehicles that display what type of fuel a vehicle uses. For passenger vehicles, these are typically found on the back of the vehicle. This is the first clue telling first responders what they need to be prepared for.
The distinct properties of each fuel type necessitate specific safety considerations. The rest of this article covers the major safety themes associated with several alternative fuels and provides resources for additional in-depth guidance.
Fuel Safety Highlights and Resources
For a comprehensive guide on alternative fuel safety, see National Fire Protection Association (NFPA) Emergency Field Guide for all alternative fuels. This guide is free to download and provides important safety information for first responders.
Hybrid Electric & Electric
Batteries in hybrid and electric vehicles can catch fire if a thermal runaway is triggered by a collision. Battery fires require more water than fires in conventional vehicles because batteries need to be cooled down for the fire to be fully suppressed. The water should be directed toward the high-voltage battery, often located beneath the vehicle, in order to cool it down and stop thermal runaway.
An additional step is to ventilate the passenger interior of the vehicle. Damaged batteries can release flammable gas which can accumulate in the passenger area.
Finally, electric shock risks are low. There are steps to take to ensure the high-voltage battery does not electrify the entire vehicle, however the batteries are designed not to electrify the vehicle chassis even when damaged. Further, the water applied when cooling a battery down is unlikely to become significantly electrified.
- NFPA Emergency Response to Incident Involving Electric Vehicle Battery Hazards Report Best Practices and FAQs from Part 3 of report on pages 191-200.
- NFPA collection of emergency response guides from 35+ alternative fuel vehicle manufacturers.
- Video – Overview of tactical considerations and best practices for extinguishing fires in hybrid and electric vehicles.
- Video – Lithium-Ion Battery Fires in Electric Vehicles and the Safety Risks to Emergency Responders.
- NFPA Electric and Hybrid Vehicle Quick Reference Guide Access
- Tesla Supercharger Charging Station Emergency Response Guide
Liquefied Natural Gas
Liquified natural gas is stored at extremely cold temperatures and under high pressure. Personal Protection Equipment must be used to prevent any liquid from touching exposed skin and causing frostbite. If there is a fire at the accident site, the LNG tanks must be kept cool by applying water to them. The tanks can explode if temperatures become too high.
- First Responder Guide: CNG and LNG Vehicle Fuel Systems.
- Liquified Natural Gas Firefighting. See relevant sections.
Compressed Natural Gas
Compressed natural gas tanks are different than liquefied natural gas tanks. In the event of a fire, the tanks have Pressure Relief Devices activated by heat which will vent the natural gas out of the tank. The vent is often located away from the tank. Water should not be applied to cool the tank because it will prevent the Pressure Relief Device from activating. This risks a high-pressure explosion.
Biodiesel
Biodiesel is less flammable than conventional diesel and gasoline. Not all biodiesel vehicles operate on 100% biodiesel fuel and are instead blended with conventional diesel. There is a higher risk for fire in situations where blended biodiesel is used.
E85/Flex Fuel
Ethanol fuel interacts differently with water than gasoline or diesel. Consequently, ethanol fires must be put out using alcohol-resistant foam instead of water. Fires involving fuels with a high concentration of ethanol, like E85, will not produce large amounts of smoke when burning. These fires may not be easily visible unless the flames can be seen.
- Video – Ethanol Emergency Response Considerations
Hydrogen
Hydrogen requires less energy to ignite than gasoline or natural gas. If the storage tank is damaged in a vehicle collision and hydrogen is being released, it is likely a fire will break out. However, hydrogen fuel cell vehicles are designed to avoid this scenario even in vehicle accidents.
- Training – Center for Hydrogen Safety First Responders Micro Training Learning Plan.
Failing to plan is planning to fail. Being aware of the unique safety considerations for alternative fuels is key to protecting its users and first responders.
