Turlock Police believe narcotics manufacturing was the cause of a Tuesday night explosion at the Briarwood Apartment complex in Turlock.

Turlock Police Drug Unit was called out to the Briarwood Apartments to investigate the cause of the explosion. The unit determined the explosion was caused by the attempted extraction of THC from marijuana, said Turlock Police Lt. Ron Reid.

THC, the main mind-altering element of marijuana, is most commonly extracted by passing pressurized butane gas through a tube containing marijuana. The butane then evaporates, leaving behind concentrated THC known as butane hash oil or “honey oil.”

Police originally responded to reported vandalism in progress at the 3300 block of Fosberg Road Tuesday night when they became aware of the explosion. Witnesses saw two people running away from the apartment.

No known injuries have been reported at this time. The explosion did blast a door off its hinges and broke several windows.

The Briarwood Apartments are located on the corner of Monte Vista Avenue and Fosberg Road near the California State University, Stanislaus.