Last updated : July 14, 2025
With more than half of all states permitting the sale, possession, and use of marijuana on either a medical or recreational basis, employers throughout the country are finding it harder and harder to enforce drug-free workplace laws. While testing for marijuana in states where medical or recreational use is legal can seem like a dicey prospect, there are many situations in which such testing is not only necessary, but appropriate.
However, it’s important to learn more about the legal principles supporting cases in which marijuana drug testing has been upheld to ensure that you’re operating within the bounds of the law. Failing to do so could set you up for a potential wrongful termination lawsuit, and even if you prevail, defending your business can be an enormous expense. Read on to learn more about the circumstances in which you can test employees for marijuana use.
Permissible Reasons To Drug Test
Industries or businesses that are subject to federal regulations may be required to drug test employees for health or safety reasons. For example, airline pilots, commercial truck drivers, and ship captains may be required to submit to periodic drug tests in order to maintain their respective licenses. However, the vast majority of private businesses aren’t subject to any laws or regulations requiring them to drug test their employees.
On the other hand, there are a number of legitimate reasons for an employer to voluntarily conduct its own drug testing program, including:
- Maintaining workers’ compensation coverage
Most states require employers to maintain a workers’ compensation insurance policy. The terms and conditions of these policies can vary by state and provider, but many will require employers to drug test employees (or offer discounts or incentives for employers that have a drug testing program).
- Promoting employee safety and reducing insurance costs
Many studies have shown the negative effects employee drug and alcohol use can have on workplace productivity. Having a drug testing policy can promote employee retention by helping you select only the highest-quality workers. In addition, umbrella insurance policies or other employer-targeted liability insurance policies can offer discounts and rate incentives if you provide proof that you test your employees for illicit substances.
Drug Testing for “Legal” Substances
Most of the states that have legalized recreational marijuana, and some states that have legalized medical marijuana, have carved out specific exceptions permitting employers to continue their existing drug testing policies. If your state has such a provision in its marijuana legalization law, it’s likely you’ll be able to continue to drug test without worrying about the legality of marijuana.
There are only a few court cases that have directly addressed an employer’s ability to fire (or refuse to hire) an employee who tests positive for marijuana. However, despite the increasing pressure for marijuana legalization nationwide, these cases have almost all been decided in favor of the employer. Many of these cases have been decided on the basis of marijuana’s continuing illegality under federal law (essentially rendering moot any state laws prohibiting employers from drug testing for “legal” substances) and may no longer apply if the federal government opts to change the way it classifies marijuana.
Because the federal government maintains that marijuana is a controlled substance with no medicinal value, most doctors are reluctant to “prescribe” it to patients for fear of having their prescription privileges revoked. As a result, it may be necessary to delineate between legally-prescribed drugs versus legally-recommended drugs to ensure that your workplace’s drug-testing policy addresses marijuana use.
But in general, as long as your drug testing policy is established and implemented to further a legitimate business purpose (like maintaining workers’ compensation coverage, reducing the risk of work-related accidents, or reducing your liability insurance premiums), you should be able to continue your current drug testing policy without concern.
