Last week, a fire broke out at the General Motors Technical Center battery research lab in Warren, Michigan. General Motors has since said the fire was caused by a battery that was being tested under "extreme stress." Engineers were trying to get the pack to fail, which it did, but not to ignite, which it also did when gases leaked out and somehow caught fire.

There's one detail we have not heard yet, and that's how much the fire could end up costing GM: up to $5 million, the The Detroit News reports, based on information that the automaker's representatives submitted in a police report. The local fire department has estimated that the damage could be closer to $3 million, with one million of that due to property loss – at least two labs were damaged – and $2 million worth of damage to the labs' contents. An investigation into the cause and extent of the fire continues.

The battery pack involved was not the same as the one used in the Chevrolet Volt and GM says that the incident has not negatively affected Volt sales. Media reports have suggested the battery is be intended for the Spark EV program and that the prototype battery pack was made by A123 (which has had other battery issues recently). Multiple people were injured in the fire but only one remains in the hospital because of "an estimated four-inch gash to the back of his head."