DETROIT (AP) -- A person briefed on the matter says leaking coolant is the likely cause of fires that broke out in the Chevrolet Volt's battery after government crash tests.
The person says General Motors engineers are developing structural changes to make the electric car and the battery pack more crash-resistant.
The person says the coolant did not catch fire, but it crystallized and created an electrical short that caused the fires. The person didn't want to be identified because the findings are not final.
Federal safety regulators started investigating the Volt's battery last month after three fires.
The flames came seven days to three weeks after the crash tests. GM says there's no threat of fire right after a crash. It also says no Volts have caught fire after real-world crashes.