Reports are surfacing that the explosion in a Butchertown apartment building was caused by a marijuana drying operation.The explosion was reported shortly after 10:00 this morning at 914 Franklin Street, a three-unit apartment building. According to Louisville Fire and Rescue, the occupant of one apartment was using a butane torch to dry marijuana. The fire spread to clothes, and caused several butane canisters to explode.Originally, MetroSafe responded by sending its clandestine lab team, because it was possible the explosion was caused by a meth lab. Arson investigators remain on the scene.One person was transported to University Hospital with minor burns.