California Code, Government Code - GOV § 12954

(b) Except as specified in subdivision (c), it is unlawful for an employer to request information from an applicant for employment relating to the applicant's prior use of cannabis.

(c) Information about a person's prior cannabis use obtained from the person's criminal history is subject to subdivisions (a) and (b), unless the employer is permitted to consider or inquire about that information under Section 12952 or other state or federal law.

(d) This section does not permit an employee to possess, to be impaired by, or to use, cannabis on the job, or affect the rights or obligations of an employer to maintain a drug- and alcohol-free workplace, as specified in Section 11362.45 of the Health and Safety Code, or any other rights or obligations of an employer specified by state or federal law or regulation.

(e) This section does not preempt state or federal laws requiring applicants or employees to be tested for controlled substances, including laws and regulations requiring applicants or employees to be tested, or the manner in which they are tested, as a condition of employment, receiving federal funding or federal licensing-related benefits, or entering into a federal contract.

(f) This section does not apply to applicants or employees hired for positions that require a federal government background investigation or security clearance in accordance with regulations issued by the United States Department of Defense pursuant to Part 117 of Title 32 of the Code of Federal Regulations, or equivalent regulations applicable to other agencies.

(g) This section shall become operative on January 1, 2024.