A car exploded at the parking lot of BJ’s Wholesale Club in Stoneham on Sunday afternoon, according to Massachusetts State Police. State Police Lieutenant Daniel Richard said no one was injured in the explosion, which occurred at about 3:40 p.m. at the parking lot of the store, located on Cedar Street. State troopers from the Medford barracks responded, well as the State Police Bomb Squad, and Stoneham fire and police. State Fire Marshal Stephen Coan reported that the explosion was caused by a remote key that, when hit, caused vapors in the car to ignite. The vapors, he said, were present due to plumbing equipment the owner was storing in the car. Several other vehicles in the parking lot were also damaged.