US auto safety regulators declared General Motors's electric Chevy Volt safe on Friday after months of investigation into the risk of post-crash fires in its lithium battery.
The National Highway Traffic Safety Administration said that its tests concluded that "no discernible defect trend exists" in the Volt, the company's main entrant in the market for plug-in electrics.
In addition, it said, recent modifications to the car by GM will reduce the chance that the battery will be damaged in side impacts.
"Based on the available data, NHTSA does not believe that Chevy Volts or other electric vehicles pose a greater risk of fire than gasoline-powered vehicles," the agency said.
"NHTSA remains unaware of any real-world crashes that have resulted in a battery-related fire involving the Chevy Volt or any other electric vehicle," it said.
The government undertook a safety investigation into the Volt after a damaged lithium battery in the car caught fire three weeks after a crash test.
Two other batteries caught fire in subsequent tests in which regulators intentionally damaged the battery compartment and broke its coolant line.
The safety regulator said its testing showed that a fire is only possible when the battery is smashed and coolant has leaked.
After the initial reports, GM moved to have dealers reinforce an existing portion of the Volt's safety structure to better protect the battery pack, as well as modifications to prevent coolant overfill.
GM has sold 8,000 Volts since its launch just over a year ago, less than the 10,000 units forecast.