Multiple hash oil laboratories across the county were raided this week after a year-long undercover operation by the Drug Enforcement Administration.

Nine people were arrested Tuesday during Operation Shattered Dreams, when DEA agents served search warrants to a number of locations in San Diego, Spring Valley, Chula Vista and El Cajon.

Inside some of the spots, investigators discovered active, illegal butane hash oil laboratories

Agents seized a large amount of hash oil, $25,000 in cash, an assault rifle, marijuana and hash oil packaged for sale.

Nicknamed “dabs,” “earwax” and “shatter” on the street, hash oil is made from marijuana using flammable butane to extract concentrated levels of THC – the active, mind-altering ingredient in cannabis.

Hash oil has THC levels of between 75 to 85 percent, compared to marijuana’s 23 to 35 percent, the DEA says, and a gram of the oil sells for $40 to $80.

However, using butane makes the production dangerous. Without proper ventilation, butane can explode if something sparks.

The DEA says hash oil labs are to blame for roughly 20 explosions and fires in San Diego County since Oct. 2013.

In many of the incidents, people have been injured and residents displaced.

“The number of explosions and fires that we have had in San Diego County just this year make Hash Oil cases a priority,” said DEA Special Agent in Charge William R. Sherman in a release. “The people who are using dangerous chemicals to extract Hash Oil do so without concern for anything other than making a profit”

San Diego Hazmat teams will now work to clear the busted hash oil labs of dangerous chemicals and equipment.

The nine people arrested face a slew of charges, including manufacturing a controlled substance, cultivation of marijuana, possession of marijuana for sale, possession of concentrated cannabis, child endangerment and possession of an illegal assault rifle.