The National Highway Traffic Safety Administration is investigating the safety of lithium-ion batteries after a Chevrolet Volt caught fire at its test facility several weeks after being crash tested by the federal agency. “NHTSA has concluded that the crash test damaged the Volt's lithium ion battery and that the damage led to a vehicle fire that took several weeks to develop after the test was completed,” NHTSA says in a statement.

General Motors and NHTSA said there have been no other reports of fires in Chevy Volts that have been sold to consumers, The Detroit News reports. “News of the fire comes as automakers try to convince American motorists that electric cars are a viable alternative to traditional gasoline-powered vehicles.”

Jim Federico, General Motors chief engineer for electric vehicles, says in a statement, “First and foremost, I want to make this very clear: the Volt is a safe car. We are working cooperatively with NHTSA as it completes its investigation.”

The Chevrolet Volt’s lithium-ion battery is made by LG Chem Ltd., Bloomberg reports, and will undergo further testing by NHTSA and the Energy Department “to see if they can replicate the condition that led to the fire.” Nissan, Tesla and Ford also use lithium-ion batteries in their electric vehicles.

NHTSA says, “Let us be clear: NHTSA does not believe electric vehicles are at a greater risk of fire than other vehicles.” NHTSA lists some tips on its site for drivers of electric vehicles and first responders in the event of a crash.

The 2011 and 2012 Chevrolet Volt received five out of five stars from NHTSA in side crash tests, as well as for rollover risk. The Volt is rated four stars in frontal crash tests and has a five-star overall safety rating.

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