A safety investigation into the Chevy Volt is now behind General Motors.
The National Highway Traffic Safety Administration on Friday said that it has ended an inquiry into potential safety problems with the battery-run Chevy Volt.
"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 in a statement.
Last year, the NHTSA started a safety defect investigation after a side-impact collision test caused a fire three weeks after the test. That and subsequent tests led GM to make modifications to reinforce the battery pack and the coolant system.
The impact test caused a leak in the liquid coolant leaked system and, after three weeks, the coolant crystallized. Current from the battery, which had not been drained, caused the coolant to ignite.
The NHTSA said that "no discernible defect trend" exists and that the changes GM made should lessen the potential for problems.
There have not been any real-world battery-related fires with Volts. All vehicles run some risk of fires in a collision, the NHTSA noted. Consumers, emergency response workers, and tow truck operators should be aware of the attributes of electric vehicles to be safe and take safety precautions, such as draining the battery after a severe collision.