Can the Use of Medical Marijuana Affect a California Workers’ Comp Claim?

 Posted on October 02, 2026 in Denied Claims and Appeals

California allows medical cannabis use for qualifying patients. Still, marijuana use can raise questions after a workplace injury. This is especially true if an employer claims that cannabis played a role in the accident.

Medical marijuana use does not automatically prevent you from receiving workers’ compensation benefits. However, the cause of your injury could be an important factor. If cannabis becomes an issue in your claim in 2026, our Santa Clara County, CA workers’ compensation lawyer can review what happened and explain your rights.

When Can Marijuana Use Affect a California Workers’ Comp Claim?

California workers’ compensation is generally a no-fault system. However, marijuana use can affect a workers’ compensation claim if an employer argues that the worker was intoxicated and that the intoxication caused the injury.

Under California Labor Code Section 3600, an injury is not covered if it was caused by intoxication from alcohol or the unlawful use of a controlled substance. The employer must prove that the worker was intoxicated and that the intoxication was a proximate or substantial cause of the injury.

For example, a worker could use marijuana the night before work and later fall when a ladder breaks. The earlier marijuana use does not explain why the ladder failed. However, marijuana use could become relevant to the claim if there is evidence that the worker was impaired and that the impairment contributed to the accident.

Does a Positive Marijuana Test Prove You Were Intoxicated at Work?

A positive marijuana test does not automatically prove that cannabis caused a workplace accident. A test can detect prior cannabis use after its effects have worn off.

Because of this, proof of cannabis use is not always proof of impairment at the time of an injury. Other evidence can help show what caused the accident.

This can include medical records, witness statements, incident reports, and details about workplace conditions. An employer that raises intoxication as a defense must support that claim with their own evidence.

Does California Protect Marijuana Use Outside of Work?

According to California Government Code Section 12954, covered employers generally cannot punish an employee for lawful cannabis use off the job and away from the workplace. The law also limits employment decisions based on certain drug tests that show past cannabis use.

However, the law does not allow employees to use or possess cannabis at work. It also does not protect workers who are impaired while working. Some workers are also excluded from the law, including employees in the building and construction trades.

These rules protect certain off-duty conduct, but they do not decide whether a workplace injury qualifies for workers’ compensation. If marijuana use becomes part of a workers’ comp dispute, the issue is whether it affected the injury.

Can Medical Cannabis Be Used to Treat a California Work Injury?

Medical cannabis now has a specific place in California’s workers’ compensation treatment guidelines. In June 2025, California added a Cannabis Guideline to the Medical Treatment Utilization Schedule (MTUS). It addresses the use of cannabis for certain types of pain.

The MTUS helps doctors and insurers evaluate whether treatment is medically necessary for a work injury. However, the Cannabis Guideline does not recommend cannabis for typical work-related conditions. It found insufficient quality evidence that cannabis is effective for common problems such as back pain, chronic radiculopathy, neuropathic pain, and other acute or chronic pain conditions.

The addition of the guideline therefore does not mean workers’ compensation will pay for medical cannabis. Instead, it provides evidence-based guidance for evaluating cannabis as a treatment.

What Should You Do if Marijuana Use Becomes an Issue in Your CA Workers’ Comp Claim?

Do not assume that your workers’ compensation claim will be denied simply because marijuana use comes up after your injury. The evidence still needs to show what caused the accident.

If cannabis becomes an issue, you can take steps to protect your claim:

• Be honest with your doctor about cannabis use and other medications.
• Keep copies of medical records and accident reports.
• Write down the names of anyone who saw the accident.
• Save photographs or other evidence showing how the injury happened.
• Speak with an attorney if the insurer claims cannabis caused your injury.

Keep this information organized in case the insurer questions whether marijuana played a role in your injury. Your attorney can help you investigate and challenge the insurer's claims.

Contact a Santa Clara County, CA Workers’ Compensation Lawyer

If your employer or its insurer has raised concerns about cannabis use, the attorney at Raul Martinez Injury Law Firm can help you with your claim. Attorney Raul Martinez has over 15 years of legal experience and understands the challenges of the California workers' compensation process.

For a free consultation, contact our Gilroy, CA workers’ compensation attorney or call 408-848-1113 to discuss your claim.