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Federal safety board: Battery fires pose risks, urges automakers to craft response guides

Riley Beggin
The Detroit News

Washington — The National Transportation Safety Board urged automakers to create comprehensive emergency response guidelines for fires caused by high-voltage lithium-ion batteries used in electric vehicles — after determining they pose a safety risk to first responders.

The report released Wednesday comes after four investigations by the board finding that the batteries are dangerous to firefighters and medics at high-speed EV crashes, as they may reignite even once they've been put out a first time. There are also gaps in research on the batteries' risks, they found.

The agency recommended that automakers create emergency response guides for fighting fires caused by the batteries — including how to prevent them from reigniting and how to safely store them when they've already been damaged — and prioritize research on battery hazards.

It also recommended that the National Highway Traffic Safety Administration consider whether an automaker has created such a guide when it determines its safety rating under the New Car Assessment Program.

A Tesla SUV crashed into a garage in Orange County, Calif. in 2017 and the battery caught on fire. The battery later reignited while the vehicle was being loaded onto a tow truck.

The recommendations come at a time when automakers are rolling out multiple new electric vehicle models, with many in the industry perceiving an inflection point in switching from gasoline power to cleaner electricity.

The four investigations by NTSB all involved Tesla Inc. vehicles, three of which burst into flame after severe high-speed crashes and one from internal battery failure. The three damaged in crashes reignited after firefighters put them out.

Tesla did not immediately respond to a request for comment on the board's recommendation. 

The agency also notes other manufacturers have had problems with battery fires, including General Motors Co.'s Chevrolet Volt in 2011, two BMW AG EV models in 2017 and 2019, and Mitsubishi Motors Corp.'s Outlander PHEV. Late last year, General Motors also voluntarily recalled tens of thousands of Chevrolet Bolt EVs after discovering battery fires.

The Alliance for Automotive Innovation, an advocacy group representing major automakers that sell vehicles in the U.S., released a statement Wednesday saying its members "will carefully review the board’s recommendations."

"As the industry transforms to an electric future, we are continuing to work with the National Fire Protection Association, NHTSA, the Society of Automotive Engineers, and others to further enhance safety," the statement read.

The agency in its Wednesday report also asked firefighter and auto towing associations to inform members about fire risks and how to deal with energy remaining in the battery after a crash, and on how to safely store a vehicle with a damaged battery.

NHTSA also should build a coalition to research ways to de-energize batteries and reduce hazards from thermal runaway, a chemical reaction that causes uncontrolled battery temperature and pressure increases.

A Tesla SUV crashed into a highway barrier in Mountain View, Calif. in 2018. The battery, which set on fire during the crash, reignited while the vehicle was being stored in an impound lot and again five days later.

“The risks of electric shock and battery reignition/fire arise from the ‘stranded’ energy that remains in a damaged battery,” the agency said.

In an 80-page report the NTSB wrote that a review of emergency response guidelines from 36 manufacturers found that all had ways to mitigate the risk of high-voltage shocks including methods for disconnecting the battery.

But none of the guides spoke to limiting the risk of energy stored in the batteries, such as procedures for minimizing reignition or instructions on where and how to spray water to cool the batteries, the agency said.

One way to deal with damaged batteries is to pull them from the vehicle and soak them in a saltwater bath to discharge the energy, the NTSB wrote.

The Associated Press contributed.