Larkspur Man Pleads Not Guilty to Drug Charges from Alleged Hash Oil Explosion in San Anselmo

A 22-year-old Larkspur man pleaded not guilty Thursday to multiple drug charges related to a Feb. 28 explosion and subsequent fire in the garage of his parents' Tunstead Ave. home.

Addison Zweig entered his plea before Marin County Superior Court Judge James Ritchie. He faces a maximum of 7 years in prison if convicted of felony manufacturing of illegal narcotics. Zweig also faces charges of maintaining a place where narcotics are manufactured, possession of concentrated cannibis, unlawfully causing a fire and possession of a controlled substance. Some of the charges resulted from a search of the brothers' apartment in the Larkspur Landing area.

The charges stem from a Feb. 28 incident in which Zweig and his 20-year-old brother Elliot were taken to Kaiser Permanente Medical Center with burn injuries after firefighters responded to a fire in the garage of a Tunstead Ave. home owned by their parents. 

Based on interviews with the two men, the Marin County District Attorney's Office decided not to pursue charges against Elliot Zweig, according to Deputy District Attorney Sean Kensinger.

In Thursday's hearing, Ritchie overruled defense attorney Douglas Horngrad's assertion that the allegation against Zweig – that he was using butane gas to withdraw concentrated THC out of cannibis to make hash oil – did not rise to the level of manufacturing illegal narcotics. The charge often involves operation of a methamphetamine lab or mixing "recursor" chemicals into an illegal substance.

Both Horngrad and Kensinger said afterward that they intend to hold settlement talks on the matter.

"My expectation is that the case will settle," Horngrad said. "My client is very remorseful."

Horngrad said Zweig is "mostly fully recovered" from second-degree burns on his arms.

Ross Valley Fire Department personnel responded to the Feb. 28 to find the garage adjacent to the house was ablaze. Elliot and Addison Zweig sustained first-degree burns to the face and second-degree burns on his arms, respectively, according to fire officials.

An ensuing investigation by the Marin County Major Crimes Task Force established evidence that the men were allegedly engaged in making “honey oil,” an extract from marijuana, according to Sgt. Pierre Ahuncain.

Ahuncain explained that the process involves the use of butane gas and “there were dozens of cannisters” in the garage. He said a build-up of butane gas in the garage, which had poor ventilation, was probably triggered by an unknown source of ignition. 

Ahuncain said honey oil has grown in prevalence over the past year or two; it is similar to hashish oil but more potent.