Training for EV fires

“The fire that erupts with lithium is more violent, and it erupts quickly and at high heat,” said Jennifer Mecham, fire inspector at San Mateo Consolidated Fire Department. “The smoke will self-ignite and so it's different than a normal fire.”

While water typically helps suppress fires in part by restricting oxygen, Mecham said EV fires are different.

“There’s an added level of complexity in that it’s its own oxidizer. It doesn’t need oxygen to survive, so pouring water on it doesn’t suffocate it,” she added.

The problem is further exacerbated in parking garages and subgrade structures. The fires produce high temperatures at a much quicker rate, and the smoke can self-ignite, increasing the risk of spalding, or weakening concrete, subsequently putting an entire building structure at risk.

“When you're dealing with an EV vehicle in subgrade structures, tactics-wise it's very difficult because they produce a lot of smoke, and sometimes they can ignite,” said Andy Martinez, fire captain at San Mateo Consolidated Fire Department. “That poses a lot of risks, especially when you're talking about these large buildings that they're going to start building over the next few years.”

With EVs, firefighters are trained to contain the immediate area while letting the fire eventually burn out on its own.

“The practice for us is to protect the exposure to the building and try to let the vehicle burn itself out,” Martinez said. “Because then the batteries aren’t a threat of going into thermal runaway.”

According to data from the California Energy Commission, about a quarter of all car sales in San Mateo County last year were EVs, and this year is trending in a similar direction.

While there haven’t been a large number of EV fires recently — apart from some in South City and another in San Mateo — it still poses serious safety risks for firefighters who are not properly trained, Martinez added. In Palo Alto, firefighters were injured when transporting batteries that went into thermal runaway. Other injuries have occurred in fire departments in Sacramento and other states, like Arizona and Colorado. Just a few months ago, firefighters in Madrid died after responding to an EV fire in a parking garage, which turned into a thermal runaway event.

And it’s not just EVs with which fire departments have to contend. House fires with solar panels and lithium battery-infrastructure is always a concern. The presence of e-bikes and e-scooters in a home necessitates a more thorough protocol that can result in more time getting to the fire itself — especially when in a multi-residential building.

“No more can we just go in there and focus solely on the fire. We have to be aware if there is an e-bike or scooter, because you can't just go past it,” Martinez said. “What was once a clean run to the scene of the fire can now be compromised.”