Flames gutted a storage unit near Dulles Airport on Sunday.
The two-alarm fire jumped from the first to second floor at the Public Storage facility in Herndon, Va. A column of smoke visible from six miles away hung over the scene throughout the afternoon.
Investigators said a halogen light in one of the storage units exploded, sparking the fire.
One civilian sustained minor burns and was quickly released from the hospital.
Firefighters required several hours to subdue all hot spots. Centreville Road was shut down during the operation.
Damages have been estimated at $1.6 million.