On Sept. 19, California Gov. Gavin Newsom signed Assembly Bill 2188 into law, enacting restrictions effective Jan. 1, 2024, on employers’ use of cannabis metabolite testing to penalize existing employees and candidates for employment. AB 2188 lends definition to an emerging nationwide landscape of adjustments in state employment regulation to increasingly permissive medical and recreational cannabis laws. AB 2188 does not apply to employment in the building and construction trades. It also does not apply to employment in positions requiring federal background investigations or security clearances, or positions otherwise subject to testing requirements under state or federal law. Cannabis metabolites are detectable days or weeks after cannabis use, and do not indicate impairment. The new law targets cannabis testing that captures off-hours, off-site use, and does not prohibit employer penalization of impairment, including via tests that identify psychoactive cannabis constituents in bodily fluids. The law cites the availability to employers of “multiple types of tests that do not rely on the presence of nonpsychoactive cannabis metabolites,” including tests which “measure an individual employee against their own baseline performance.” AB 2188 explicitly does not permit any employee to possess, use or be impaired by cannabis at work.