The National Higway Traffic Safety Administration has officially closed the book on its investigation into the Chevrolet Volt. The result finds that "no discernible defect trend exists" and "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."

NHTSA supports the modifications developed by General Motors to address "specific attributes" particular to electric vehicles in the event of a crash. GM is retrofitting the nearly 8,000 Volts sold with additional side reinforcements and a sensor to detect coolant leaks, which was found to be the cause of the short-circuiting battery and resulting fires. The agency also issued guidelines for first responders and auto shops coming who encounter Volts that have been involved in accidents.

That means the safety fire has been put out, but a political fire still burns in Congress. General Motors CEO Dan Akerson and NHTSA head David Strickland will face a House panel in a few days to answer questions about the timeline of the investigation. Follow the jump to read NHTSA'* statement on the investigation.