Some of the first states that legalized the use of medical or recreational marijuana did so with warnings to users that state law provided no protections from drug testing or loss of employment due to the presence of marijuana in such test results. As legal marijuana use in these states has become normalized, some are reconsidering whether it makes sense to allow such use while still subjecting workers to the loss of their jobs.

Last week, California Governor Gavin Newsome signed legislation that will prohibit California employers from discriminating against applicants or employees due to off-duty marijuana use. The new measure, which takes effect on January 1, 2024, means that the mere presence of marijuana in an employee’s system, or their admission of use away from work, cannot serve as the basis for disciplinary action.

The new law contains a few important exceptions. First, it does not affect employers’ ability to use pre-employment testing to identify and exclude persons based on the presence of psychoactive cannabis metabolites. Most current drug tests identify non-psychoactive metabolites, and the law is unclear on exactly what tests can be used for this purpose. Presumably, these tests would measure impairment at the time of testing.

The law also excludes the construction and building trades industries from the new prohibitions. It does not change limitations on employee drug testing already in place under California law. The law also does not apply to workers subject to federal drug testing or use requirements.

Other states that legalized marijuana some time ago may follow this example. States that have more recently passed marijuana legalization laws are more likely to address this issue up front, setting forth in the legalization legislation employers’ ability to exclude users from the workplace.