A report of a structure fire in Lower Lake last Thursday led officials to discover what they called a large-scale lab for making ultra-concentrated "honey oil" from marijuana, the Lake County Sheriff's Office said.

Officials have made no arrests in the case, said Lt. Steve Brooks in a report issued Monday.

Firefighters responding to the structure at 20,000 block of Morgan Valley Road late Thursday morning reported seeing what they thought was a lab. They also reported that people were leaving the area.

The Sheriff's Narcotics Task Force responded and found the lab, where butane was used to heat marijuana and concentrate it into a product called honey oil, Brooks said.

Detectives got a search warrant for the property and found several thousand burned butane canisters, along with nearly two thousand full canisters, Brooks said. They also found 237 pounds of marijuana trimmings in plastic bags outside the burned home.

In a nearby metal storage container, they found 8.1 pounds of butane honey oil, which Brooks said can sell for $8,000 per pound. The total value of the oil was estimated at more than $22,500.

The fire appears to have started when a PVC tube used in the extraction process exploded, Brooks said.

Producing butane honey oil commercially is a growing trend and a felony crime, Brooks said.

Anyone with information on this or other labs should call 263-3663.