The process of extracting hash oil from marijuana is a growing and dangerous trend. In recent weeks, hash oil has been linked to three powerful explosions in Northern California.
"Hash oil isn't necessarily something new, but this process appears to be a relatively new way to do it," said Lt. Paul Garaven with the Tustin Police Department.
Garaven says two men suffered severe burns in July after they attempted to make hash oil in their Tustin garage. The powerful blast blew off the garage door and pushed out walls.
YouTube is full of "how to" videos that show how to make hash oil.
"It requires marijuana to be processed with butane and the resulting oil or liquid that comes out of that process results in concentrated liquid cannabis," said Garaven. "You're getting a stronger dose and a more significant high."
But the process is highly flammable. In February, FEMA put out a web advisory to fire and law enforcement agencies warning about the dangers associated with hash oil, saying "the extraction method appears to be more common on the West Coast."
Officials say the explosions caused by the process can sometimes be misidentified as a pipe bombs or meth labs.
"Anytime you get chemicals, particularly explosive chemicals, there is always a concern, particularly in residential areas," said Garaven.
Tustin police say that while legal medical marijuana is allowed in the state of California, production of hash oil is not. In fact, the two men in that July case, in which their garage exploded, have been charged with felonies.