Two men are arrested by Longmont Police in connection with a fire in a garage at 30 James Circle on Wednesday. A third man was transported to Longmont United Hospital with severe burns. (Matthew Jonas/Times-Call)

Longmont police: Garage explosion set off by THC extraction

Longmont police believe an attempt to extract THC, the active ingredient in marijuana, caused an explosion in a James Circle garage Wednesday in south Longmont.

Arriving officers found three men still in the garage dealing with flames and burning items. Police initially suspected that the explosion might have been caused by methamphetamine production or the extraction of THC from marijuana. One man suffered serious burns, a second had some burns to his face, and a third was uninjured. The man with serious burns was taken to Longmont United Hospital for treatment.

Longmont police Cmdr. Jeff Satur later said that police suspect the men were extracting “hash oil,” a potent derivative of marijuana.

The process uses butane as a solvent to remove the oil from marijuana plant matter. There is no flame used, but the butane, which is heavier than air, can explode if it comes into contact with a spark or flame.

According to a Federal Emergency Management Agency alert released earlier this year, “explosions in residences and hotels around the country are being traced back to (the) process. … Reported fires and explosions have blown out windows, walls and caused numerous burn injuries. …”

“Initial explosions can lead to secondary explosions and fires,” the FEMA alert said. “In states with legalized use and availability of medical marijuana, these incidents appear to be increasing.”

All three were arrested on suspicion of fourth-degree arson and conspiracy to commit fourth-degree arson. The man who was hospitalized also was wanted on two outstanding warrants.

A resident called police for help at 12:41 p.m. and reported that one man in the garage called out, “Don’t call the police!”

Dan Krauss, a neighbor, said he heard glass breaking, saw flames and immediately hurried over to see what he could do to help.

“I thought someone got blown to bits,” he said. “I ran over and asked, ‘Is anyone injured? Does anyone need my help?’ Everyone told him they were OK,” Krauss said, adding that police arrived while he was still checking on his neighbors.

He said he only knew the man who rented the house in passing, but said he was friendly.

Pierrette J. Shields can be reached at 303-684-5273 or

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