The call comes in to emergency dispatch: An electric vehicle is on fire near the interstate exit ramp. Fire crews rush to the scene. If the blaze involves the car’s lithium-ion battery, putting out the fire could be a challenge.
“There’s a lot of material online that we’ve read where some people say 30,000 gallons to extinguish them and up to 60,000 gallons, whereas a gas-combustion engine is around 500 to 1,000 gallons,” said District Chief Scott Douglas, public information officer for the Oklahoma City Fire Department in Oklahoma City, Okla. “It’s a lot longer on scene, a lot longer process. That’s a lot of water that you don’t want to just squirt on the ground for no reason.”
Firefighters will encounter electric vehicle fires more frequently as a growing number of Americans take to the road in the vehicles. Cox Automotive, a vehicle industry analysis and information firm, forecasted in June that automakers will sell 1 million electric vehicles this year in the United States. That’s a record and double the number sold in 2021, Cox reported. The International Energy Agency estimates the United States had a combined total of about 3 million battery electric vehicles and plug-in hybrid electric vehicles on the road in 2022.
The Oklahoma City Fire Department has taken a proactive approach by searching for new technology to extinguish EV fires quickly.
“We have a lot of vehicles coming through the Oklahoma City area,” Douglas said, “which is why we’re trying to stay ahead of the game a little bit and be more prepared for these electrical vehicle fires.” Interstates 35 and 40 intersect in the city. The department, which has 38 fire engines, also serves more than 600,000 residents in an area encompassing 621 square miles.
Douglas said fire crews can extinguish gas-combustion engine vehicle fires relatively easily because they can open the vehicle’s hood to get access to the fire.
“The bad thing with the electric (vehicle) fires that we’ve seen with the lithium batteries is that they have what they call a thermal runaway,” he explained. “Basically, in the internal mechanism of the battery, they call it a short-circuit. Once the car battery short-circuits, it can then produce basically its own fire.”
The majority of flames and heat stay inside the battery, which makes them difficult to hit with water, he said. Firefighters have to drench the battery’s outer shell with water to cool it enough to stop the thermal runaway. That can be a problem if the EV fire is on an interstate highway where there are no fire hydrants and access to water is limited, according to Douglas.
In its search for new technology to combat EV fires, Douglas said the Oklahoma City Fire Department first tested fire blankets.
Most fire blankets seem to be made of a fiberglass material with a silicone coating, he said. Two firefighters wearing personal protective equipment deprive the fire of the oxygen it needs to keep burning. The blanket also contains the heavy smoke common with EV fires, Douglas said. That prevents the smoke from obscuring the vision of passing drivers and possibly causing other accidents. Once the fire dies down, firefighters can cool the battery with water to fully extinguish the blaze.
For the test at the department’s training site, firefighters set a gas-combustion engine car ablaze and allowed it to become fully involved, Douglas said.
“We had a thermal-imaging camera going the whole time, so it showed us the variations in temperature,” he said. “It (the fire) goes from 800 to 1,000 degrees. And then, once we put the fire blanket over it, it goes down to like 150 degrees. So it’s basically suppressing the flames. Once the fire blanket was over the car for a minute or so,” he added, “we would take a hand line and squirt some water up under the fire blanket, and that cooled the environment even more. Then you pull the fire blanket off, and it allows you to access the areas you need to.”
A fire blanket can help firefighters extinguish a vehicle blaze faster and with less water, Douglas said.
“You have many storm drains around Oklahoma City that we’re trying to protect as well,” he said. “So we don’t want to squirt a bunch of water and have all this runoff going back into our water system.”
As of September, however, Oklahoma City hadn’t purchased any fire blankets because of the cost.
“They’re around $2,000 to $6,000 is kind of the range we’ve been looking at,” Douglas said. “And the bad thing is they’re not an item that you can use and reuse again. … So they’re saying anywhere from one to five uses, depending on the severity of the fire.”
Douglas said his department will continue searching for a good option for extinguishing EV fires.
The department maintains good relationships with fire departments in other communities, so Oklahoma City firefighters can call those departments to ask what they are using for EV fires, he said. That includes fire departments in California and New York, where more electric vehicles are on the road, he added.
At fire service conferences, our firefighters will talk with other firefighters, Douglas said. “You know, ‘How are you doing with this? What are you all seeing? What tools are you using?’ So the fire service is great at helping one another out.”
Oklahoma City fire staff also read numerous fire service magazines and articles. “We’re just trying to get our hands on any information we can and just making sure we’re proactive with making sure we can get these fires extinguished in a good amount of time and get our firefighters back in service,” he said. “With extinguishing agents, fire blankets, different fire-suppression efforts, there’s just not enough data out there to build a solid foundation on the route we need to go,” he added. “So we’re just kind of exploring it and trying to find the best route.”