A cannabis drug test sits on top of an employee agreement for a drug test.
NEWS AND COMMENTARY

Conflicting State, Federal Laws Make Drug Testing Policies Tricky

UPDATED
May 16, 2025
PUBLISHED
September 28, 2023
AUTHOR
Purdue Global Law School

As of August 1, 2023, 40 states and Washington, D.C., have legalized the medicinal or recreational use of cannabis. Two have decriminalized it, and seven allow the use of CBD oil containing low amounts of tetrahydrocannabinol (THC), the psychoactive ingredient in marijuana. Marijuana use — and CBD containing either any amount of THC or more than the federal limit of 0.3% THC, depending on the state — remains fully illegal in just four states: Idaho, Kansas, South Carolina, and Wyoming.

Gallup reports that as of November 1, 2024, 15% of Americans say they use marijuana, up from 7% in 2013. Americans in states where recreational cannabis is legal are 20% more likely to use it. Many of these cannabis users are in the labor force, creating a dilemma for employers that conduct drug testing.

Because of the ongoing U.S. labor shortage, employers have an incentive to relax drug testing policies to attract more workers. However, marijuana use remains illegal at the federal level. The number of workplace accidents and injuries involving employees under the influence of drugs is at an all-time high. Many employers will need to reevaluate their drug testing policies to reduce risk while ensuring compliance with conflicting state and federal laws.

Laws Requiring Drug Testing

Federal law does not generally require employers to conduct drug testing. The Drug-Free Workplace Act applies only to certain federal contractors, who must make a good-faith effort to prohibit the possession and use of drugs at worksites.

However, the U.S. Department of Transportation requires pre-employment testing of workers in safety-sensitive positions in the transportation sector. This includes drivers of commercial vehicles, commercial pilots and flight attendants, and mechanical employees of railroads, among others. These workers are subject to a range of drug tests, including pre-employment, post-accident, and random testing.

A few states also have drug-testing requirements. For example, Connecticut and Delaware require testing for the certification of school bus drivers, and Hawaii requires testing for civil service positions in the City of Honolulu. Several states offer employers discounts on workers’ compensation insurance premiums if they conduct drug testing and meet other criteria.

Federal Laws Restricting Drug Testing

Three federal statutes restrict the use of drug testing.

  • Americans with Disabilities Act (ADA). Employers can face discrimination charges for requiring employees who appear intoxicated to undergo drug testing. Several medical conditions protected by the ADA have symptoms that can mimic intoxication. Additionally, some courts have found employers in violation of the ADA for asking about legal drug use during pre-employment or pre-promotion drug testing.

  • Title VII of the Civil Rights Act of 1964. Employers must ensure that drug testing policies are generally applicable and do not single out individuals in a protected racial, gender, or ethnic category.

  • The National Labor Relations Act (NLRA). Drug testing procedures covering unionized workers must be negotiated through formal collective bargaining. This includes drug testing required by federal law. Any penalties that result from failing a drug test must also be negotiated.

State Laws Restricting Drug-Related Discrimination or Drug Testing

Eight states have laws prohibiting employers from discriminating against job applicants based on legal off-the-job marijuana use: California, Connecticut, Montana, Nevada, New Jersey, New York, Rhode Island, and Washington. Several local governments, including New York City, also have similar laws. These laws do not preempt federal or state laws that require drug testing or apply to applicants for positions that the employer has identified as safety-sensitive.

Generally, however, employers in those states cannot make initial hiring decisions based on non-psychoactive cannabis metabolites that remain present in the body weeks after use. Someone who is not impaired can test positive for marijuana. Additionally, drug testing determines only whether the individual has used marijuana, not the level of impairment.

Other states have specific procedures for drug testing, such as written policies and notification requirements. In some states, employees must be given an opportunity to explain or contest the results or have follow-up testing at their own expense. Employees may have the right to sue noncompliant employers for lost wages, attorney fees and costs, and other damages.

What Employers Should Do

A nonexistent or vague drug-testing policy can expose employers to liability. Applying the Department of Transportation requirements to all employees and disciplining employees inconsistently can create problems as well. Employers should carefully craft drug-testing policies and train supervisors on how to apply them.

Employers should work with legal counsel to determine which laws and regulations apply. In addition to understanding limitations on drug testing, employers will need to determine whether they can make hiring and firing decisions based on drug tests. They will also need to understand whether employees who are fired for failing a drug test are entitled to unemployment benefits and whether employees injured on the job while impaired are entitled to workers’ compensation. Employers with a multistate footprint may find that a single policy cannot apply to all employees.

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About The Author

Purdue Global Law School

Established in 1998, Purdue Global Law School (formerly Concord Law School) is Purdue University's fully online law school for working adults.