SANTA CRUZ -- Three men making hash oil were critically injured in an explosion and fire, Santa Cruz police said Monday.
Fire crews responded to the blast at an apartment building in the city around 1:30 p.m. Sunday. The men -- all Santa Cruz residents in their 20s -- sustained life-threatening burns, police said.
They were taken to a San Francisco Bay Area trauma center, where they were in critical condition.
Efforts to extinguish the fire were hampered by additional explosions from butane canisters, police said. But crews were able to contain the blaze and minimize damage to surrounding structures.
Hash oil is a potent marijuana byproduct that is extracted with butane from parts of the plant that are often discarded.
Without proper ventilation, butane vapors can build up and be easily ignited by an open flame or static electricity. Explosions involving hash oil production are not uncommon.
The primary blast area in Sunday's explosion points to the water heater pilot light, police said.
Sophia Tolson, who lives next door to the men, said she ran outside to see what was happening after hearing a "huge boom."
"I heard the boom and guys came out screaming," she told the Santa Cruz Sentinel (http://bit.ly/15Eisi8). "I saw one had his eyebrows missing, his shirt was melting. He looked at me and said, 'Please call 911.' "
Information from: Santa Cruz Sentinel, http://www.santacruzsentinel.com