Employment Law

Cannabis Drug Testing Rules for California Employers

By Ingrid Rainey · February 24, 2026 · 7 min read

Updated July 8, 2026

Editorial photo illustrating Drug Testing After AB 2188: What California Employers Can Still Do

California law prohibits most employers from discriminating against applicants or employees based on off-duty cannabis use away from the workplace, and from relying on tests that detect non-psychoactive cannabis metabolites. Metabolites can remain detectable for weeks and say nothing about current impairment, which is the policy rationale. Employers retain the right to a drug-free workplace — but the testing method and the documentation behind an adverse decision now matter a great deal.

Key takeaways

Decisions cannot rest on tests detecting non-psychoactive cannabis metabolites.
Impairment testing, and testing for psychoactive THC, remains permissible.
Building and construction trades and positions requiring federal background clearance are excepted.
Employers may still prohibit possession, use, and impairment on the job.

What the law restricts

The restriction is on the basis of the decision, not on testing generally. An employer may not refuse to hire, terminate, or otherwise penalize a person because of cannabis use off the job and away from the workplace, or because of a test result showing non-psychoactive metabolites.

Separately, employers generally may not ask applicants about prior cannabis use, and criminal history inquiries about certain cannabis convictions are limited.

What employers may still do

Maintain a drug- and alcohol-free workplace policy covering possession, use, and impairment on duty.
Test using methods that identify psychoactive THC rather than inactive metabolites.
Act on observed impairment documented through a reasonable-suspicion process.
Comply with federal contractor or federal funding requirements where they apply.

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Exempt categories

The building and construction trades are excluded, as are positions requiring a federal government background investigation or security clearance. Employers subject to federal testing regulations — DOT-covered drivers, for instance — continue to follow those rules.

Exemptions are read narrowly. A company that does some construction work does not exempt its office staff.

Updating the policy without creating new risk

Change the panel with your testing vendor and get written confirmation of what the new panel detects.
Rewrite the policy to speak in terms of impairment and on-duty conduct rather than any positive result.
Train supervisors on documenting observed behavior — specific, contemporaneous, and behavior-based.
Keep test results confidential and out of the general personnel file.
Coordinate with disability accommodation obligations when a medical condition is disclosed.

Frequently asked questions

Can we still do pre-employment drug testing?

Yes, provided the test does not screen for non-psychoactive cannabis metabolites as a basis for the hiring decision. Other substances may still be screened normally.

What if an employee appears impaired at work?

You may act. Document specific observations, follow a reasonable-suspicion protocol with a second observer where possible, and apply the policy consistently.

Does this protect employees who use cannabis at work?

No. On-the-job possession, use, and impairment can be prohibited and disciplined.

Are safety-sensitive roles exempt?

Only if they fall within the statutory exceptions or a federal testing regime. Safety-sensitive as an internal label is not itself an exemption.

This article is general information, not legal advice, and does not create an attorney-client relationship. Outcomes depend on the facts of each matter.

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