An explosion at a backyard hash oil laboratory on Yolanda Avenue left a 10-foot area scorched black and led police to more than 100 pounds of marijuana in the house Friday, Santa Rosa police said.
Police were concerned that one or more of the people involved in the operation may have been seriously hurt in the blast and fled the scene, Sgt. John Cregan said in a statement.
A woman inside the house, Jessica Hahn, 25, of Santa Rosa was arrested on suspicion of manufacturing a controlled substance and possession of marijuana for sale.
Police said it appeared she was inside the house when the explosion occurred about 4:15 p.m. in the yard behind a home in the 300 block of Yolanda Avenue.
Several residents called 911 to report hearing multiple explosions, police said.
The hash oil lab included multiple burners attached to butane bottles, Cregan said. The blast destroyed a canopy covering the lab, scorched two outbuildings in the yard and left shards of broken glass scattered around the yard.
Detectives searched the house and found a large amount of hash being manufactured in an interior processing area, along with the marijuana in various forms and a large amount of cash, Cregan said.
Police said it appears the lab was making "honey oil," a form of hash extracted from marijuana, often with highly flammable butane gas.
Police said the explosion was set off when the butane was "ignited by a heat source."
A man found inside the house with Hahn was released, police said.