The National Highway Transportation Safety Administration said Friday it had been looking at the Volt for months, and based its concern on a crash-test in May and three tests last week on its lithium-ion battery, CNN reported.
"The agency is concerned that damage to the Volt's batteries as part of three tests that are explicitly designed to replicate real-world crash scenarios have resulted in fire," the administration said in a news release. "NHTSA is therefore opening a safety defect investigation of Chevy Volts, which could experience a battery-related fire following a crash."
Although it said it knows of no "real-world" occurrences of fires resulting from battery problems following a collision involving a Volt, the NHTSA said, "Volt owners who have not been in a serious crash do not have reason for concern." The statement said no recall order has been issued but that could change "if NHTSA identifies an unreasonable risk of safety."
GM spokesman Greg Martin said the company has not been able to duplicate the fires, CNN reported.
The Volt has been given a five-star safety rating because it passed other tests for protecting vehicle occupants, CNN said.
A Chevy Volt whose lithium-ion battery was damaged in a U.S. government crash test caught fire this spring after sitting in storage for three weeks.
Martin says GM believes the fire occurred because NHTSA did not follow GM's recommended safety protocol.
"Had those safety protocols been followed for this test, this incident would not have happened," he said, noting this is the only crashed Volt ever to catch fire.