Police say an attempt to extract hash oil from a marijuana plant caused an apartment explosion in Mount Vernon Thursday that sent at least three people to the hospital.
It happened around 11:45 p.m. at the Ridgewood Apartments in the 400 block of Stanford Drive.
Mount Vernon police say officers arrived to find flames coming from one of the units. The impact of the blast sent glass several feet into the parking lot and walls were forced off their studs.
Lt. Chris Cammock says the injured people drove themselves to Skagit Valley Hospital. Cammock believes a fourth person also checked themselves in later with injuries. None of the injures appear to be life-threatening.
The Washington State Patrol bomb squad investigated to make sure there were no other explosives.
The complex was evacuated for two hours to determine which units were safe to return to. Five units remained closed for the investigation.
Police say the process of extracting oil from marijuana involves mixing parts of the plant with butane gas. It appears a two-liter pop bottle was being filled with butane when Thursday’s explosion happened.
Hash oil explosions are becoming more common according to the U.S. Fire Administration. The agency posted a warning earlier this year to say such incidents were becoming more common. The process is considered extremely dangerous because of improper butane ventilation.
Anyone with information that can help police is asked to call (360) 336-6271 or (360) 428-3211.
KING 5's Jake Whittenberg contributed to this report