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Marijuana in the US Workplace

Fiona W Ong and Parker E Thoeni of Shawe Rosenthal explore the legality of marijuana, both medical and recreational, in a US employment context where state and federal law can diverge wildly.

Published on 15 November 2022
Fiona W. Ong, Shawe Rosenthal, Chambers Expert Focus
Fiona W Ong
Ranked in 1 practice area in Chambers USA 2022
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Parker E. Thoeni, Shawe Rosenthal, Chambers Expert Focus
Parker E Thoeni
Ranked in 1 practice area in Chambers USA 2022
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Although marijuana remains illegal under US federal law, a majority of states have already legalised the medical use of marijuana, while an ever-increasing number of states are moving towards legalising recreational use as well. The workplace impact of these various laws poses challenges for US employers, particularly those with multi-state operations. This is complicated by the fact that, unlike for alcohol, there is currently no test for marijuana intoxication, and individuals may test positive for weeks following an incidence of marijuana use.

Relevant federal laws and regulations

There are several federal marijuana-related laws and regulations of which employers should be aware. Under the Controlled Substances Act (CSA), marijuana is a Schedule I controlled substance, meaning that it “has no currently accepted medical use in treatment” and therefore may not be legally sold, possessed or used for any purpose. Although marijuana’s illegal status arises from the CSA, the CSA is not an employment law and there are no consequences to employers under the CSA for employee use of marijuana, whether medicinal or recreational, as permitted by state law.

Employers in the transportation industry that are governed by the US Department of Transportation (DOT) regulations are required to test “safety-sensitive” employees for various controlled substances, including marijuana. The DOT regulations do not allow employees to use marijuana when off-duty, even if the marijuana was legally prescribed under state law and used outside the workplace.

"The Americans with Disabilities Act, which applies to all private employers with 15 or more employees, explicitly excludes those using illegal drugs from its coverage."

The Drug-Free Workplace Act of 1988 (DFWA) requires federal contractors with any grant or single government contract (valued at USD100,000 or more and not involving the acquisition of commercial goods) to provide a drug-free workplace. Notably, while the DFWA requires those contractor employers to take certain specific actions to establish and maintain a drug-free workplace, it does not mandate drug-testing of employees. Thus, some federal and state courts have found that compliance with the DFWA does not necessarily preclude medical marijuana use as permitted by state law.

The Americans with Disabilities Act, which applies to all private employers with 15 or more employees, explicitly excludes those using illegal drugs from its coverage. It is unclear whether the use of medical marijuana would be required as a reasonable accommodation, however. The ADA’s definition of “illegal drug” does not include the use of a Schedule I controlled substances taken under supervision by a licensed health care professional, as required for medical marijuana. Nonetheless, at least one federal court has rejected that argument, finding that such use must also be authorised by the CSA, which marijuana is not.

State medical marijuana laws

As of September 2022, 37 states and the District of Columbia have legalised the use of medical marijuana under the supervision of a doctor. Whether these state laws address any impact in the workplace varies widely. 22 of those states prohibit employment discrimination on the basis of medical marijuana use, while the remainder are silent. Regardless, an employer is (thus far) not required to allow an employee to use or be under the influence of marijuana while at work.

Beyond that, while Nevada’s law specifically requires employers to provide reasonable accommodations for medical marijuana users (ie, permitting off-duty use and/or exemptions from testing), most other laws are not that definitive. Some courts, such as those in Massachusetts, have interpreted a state’s disability discrimination law to incorporate the reasonable accommodation requirement as to medical marijuana. On the other hand, some of these laws allow – or have been interpreted by the courts or state agencies to allow – employers to maintain a zero-tolerance drug policy, even for off-duty medical marijuana use.

State recreational marijuana laws

As the use of marijuana becomes increasingly normalised in our society, many states have taken action to decriminalise marijuana possession, making it a civil offence (akin to a parking ticket) rather than a criminal one. Going even further, 18 states, as well as the District of Columbia, have legalised recreational use, with several others poised to do the same. While seven of those states have included employment protections in their law (subject to exceptions, as discussed in the next section), the others are generally silent on any workplace impact, meaning that, in some instances, employers may still enforce zero-tolerance drug policies that encompass off-duty marijuana use.

"Some of the states that have legalised medical and/or recreational marijuana have expanded employment protections for such marijuana use."

Relatedly, a number of states have laws generally prohibiting employers from taking adverse employment action against employees for legal off-duty conduct, and there have been several cases in which employees have sought to invoke these protections with regard to their off-duty use of legalised recreational marijuana. Noting that marijuana is still illegal under federal law, however, courts have thus far rejected this argument.

Additional employment protections for marijuana use

More recently, some of the states that have legalised medical and/or recreational marijuana have expanded employment protections for such marijuana use. Several laws prohibit employers from taking adverse action based on an employee’s off-duty use of marijuana, whether recreational or medical. New Jersey’s law also prohibits employers from considering certain marijuana-related criminal convictions in making employment decisions.

Certain state and local jurisdictions have also passed laws that address testing for marijuana. Some prohibit pre-employment testing for marijuana, while others also prohibit or severely restrict testing of employees. Several laws do not ban testing but prohibit employers from taking employment actions based on a positive test.

Notably, all of these laws contain exceptions where an employee’s marijuana use is prohibited by law or regulation, or would jeopardise federal funding or contracts. Some also have exceptions for employees in safety-sensitive positions (with widely varying definitions of “safety-sensitive”), either barring them from use altogether or barring use for a certain period (eg, 24 hours) before commencing work.

Permitting all use?

Some employers may decide that trying to navigate the differing requirements from state to state is simply too challenging, and that they will simply allow employees to use marijuana without restriction. While this approach may work for some employers, for others it may create liability. As noted above, certain employers may be required to prohibit marijuana use of some or all employees, perhaps with confirmatory testing, by law, regulation, or government contract. Additionally, employers with employees in safety-sensitive positions (which can include the use of heavy or dangerous equipment, or the direct care of children or sick/vulnerable adults) may need to ensure that employees are not performing such duties while under the influence of marijuana. Failure to do so could open them up to litigation by individuals who are injured by marijuana-using employees.


As this article makes clear, the workplace issues arising from employees’ use of medical and recreational marijuana are complicated. Regardless of whether an employer wishes to ban all use, permit use for any reason, or take an approach that falls somewhere in between, it is critically important for employers to consult with experienced employment counsel to ensure that they are fully compliant with all applicable laws.

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