DENVER — A string of explosions caused by people trying to make super-strong marijuana products with butane gas has Colorado firefighters on edge.
"It's probably just a matter of time until someone gets killed," said Mark Watson, spokesman for the Denver Fire Department. "We go in and there's cases and cases of butane. It's highly explosive."
Officials say there have been 31 confirmed hash oil explosions in Colorado this year, with 17 more confirmed in other states. Denver alone has seen five confirmed hash oil explosions in 2014, with at least three more under investigation.
• In San Francisco, two people were critically burned last month in a homeless encampment when their hash oil rig exploded inside a tent, authorities said.
• Bellevue, Wash., police are seeking manslaughter charges against a man they say was making hash oil when he blew up an apartment building on Nov. 5, 2013, causing more than $1.5 million in damage and injuring the town's former mayor, who later died from complications due to her injuries.
• New Jersey fire officials in January 2013 issued a special warning to the state's firefighters, saying they were seeing a "marked increase" in the problem and reminding them to wear breathing apparatus when responding to calls involving hash oil extraction.
Hash oil or "wax" is made by running butane or another solvent through a container filled with dried marijuana clippings, left over after the flowers have been cut off for smoking. The solvent strips the THC, or psychoactive compound, out of the plants, leaving behind an oily liquid that can be further solidified by heating the mixture to evaporate the butane.
Because it's heavier than air, the butane sinks to ground level, where it can be ignited by a stove's pilot light or a refrigerator's compressor motor. People making hash oil also sometimes store it in their refrigerator, where the butane continues to evaporate.
The problem isn't contained just to urban areas. A cabin in the remote town of Leadville, Colo., deep in the Rocky Mountains, blew up April 28. Authorities there say hash oil stored in a refrigerator was probably to blame, with the explosion blasting out the cabin's windows, according to photos distributed by the Lake County Office of Emergency Management.
Explosions caused by hash oil processors aren't new. In February, federal officials warned local fire and police departments about the dangers posed by hash oil extraction, which they said was predominantly a West Coast trend.
"This is absolutely a big issue for us here in Colorado, but also across the rest of the country," said Kevin Wong, an intelligence analyst with the Rocky Mountain High-Intensity Drug Trafficking Areas task force.
Hash oil production is legal in Colorado, but many commercial manufacturers have switched to more expensive but safer carbon dioxide extraction. While marijuana plants can contain about 20% THC, hash oil can contain 60% to 80% THC, Wong said.