GM battery lab explosion outside Detroit injures five (Update)

UPDATE: An explosion and fire this morning triggered by a lithium-ion battery injured five people at the General Motors Tech Center in Warren, Mich., just outside Detroit. GM says the incident required the evacuation of the Tech Center; the Detroit Free Press reports that one worker is in critical condition at an area hospital.Video from the scene shows windows blown out of the lab, part of the sprawling campus where GM engineers and designs future vehicles. Warren fire officials have said the blast was caused by a lithium-ion battery reaction, but GM has declined to specify a cause.