A June 2 California OSHA letter that recommends that the state's medical marijuana industry doesn't need special safety rules, saying that existing regulations are already adequate.  can be found at 

Cal/OSHA's review of potential marijuana regs included a 2016 meeting that attracted 120 participants. The meeting revealed that there was a lack of knowledge among medical marijuana growers, processors and dispensary operators of Cal/OSHA regulations. Worker advocates have called for specific rules to protect workers from explosion hazards during the manufacturing of concentrated forms of tetrahydrocannabinol, or THC, from cannabis buds. The process uses high-pressure gases to extract the chemical.