CANOGA PARK (CNS) – Two men were badly burned today in an explosion in one unit of a Canoga Park commercial building that authorities said apparently was being used as a drug lab.

Firefighters were sent to the 7800 block of North Alabama Avenue about 11 a.m., along with a hazardous materials team and building inspectors.

The blast, which was reported in one unit of the building, also damaged two other units and resulted in a partial roof collapse, the Los Angeles Fire Department reported.

The two men apparently were using butane in the processing of processing of “honey oil,” a cannabis concentrate, Los Angeles police Sgt. Jeff Collado told reporters.

The injured men were taken to a hospital for treatment of serious burns, according to reports from the scene.