Workplace Drug Testing in Missouri

Missouri has no statute addressing drug testing in private employment.

By , J.D. · University of Missouri School of Law

Has your Missouri employer or prospective employer asked you to take a drug test? Federal law places few limits on employer drug testing: Although the federal government requires testing by employers in a few safety-sensitive industries (including transportation, aviation, and contractors with NASA and the Department of Defense), federal law doesn't otherwise require – or prohibit drug tests.

For the most part, state and local laws determine whether an employer may test employees and applicants for drugs.

No Missouri Drug Testing Laws

Missouri is one of a small number of states that has no law addressing drug testing in private employment. This means that drug testing is not prohibited or restricted, unless it violates other legal provisions (such as a law prohibiting discrimination; see below).

Drug Testing for Recreational and Medical Marijuana in Missouri

In 2022, Missouri voters approved Amendment 3, a ballot measure that legalized the use of marijuana for recreational purposes. However, unlike in some states, recreational marijuana users don't have any specific employment protections in Missouri.

With one important exception, employers can generally test their employees for the presence of marijuana and take disciplinary action against those who test positive.

The exception in Missouri is for medical marijuana users. State law prohibits employers from discriminating against employees who hold medical marijuana cards, and they cannot fire, discipline, or otherwise discriminate against such users based solely on a positive test for marijuana. However, medical marijuana users aren't protected if they use the drug in the workplace or show up to work under the influence of marijuana.

Legal Claims for Drug Testing

Because Missouri law doesn't put any limits on workplace drug testing, employees who believe their test was illegal will have to rely on other legal theories. For example, an employer may run into legal trouble based on who is tested or how the test is conducted. Here are some examples:

  • Disability discrimination. An applicant or employee who is taking medication for a disability is protected by the Americans with Disabilities Act (ADA). Some prescribed medications turn up on drug tests, and some drugs that would otherwise be illegal (such as opiates) are legitimately prescribed for certain conditions. If an applicant is turned down because of a positive drug test, and the applicant's medication was legally prescribed for a disability, the company could be liable (unless the drug is medical marijuana).
  • Other discrimination claims. An employer who singles out certain groups of employees – for example, by race, age, or gender– for drug testing could face a discrimination claim.
  • Invasion of privacy. Even an employer that has a legitimate reason to test might violate employee privacy in the way it conducts the test. For example, requiring employees to disrobe or provide a urine sample in front of others could be a privacy violation, depending on the circumstances.
  • Defamation. An employee might have a valid claim for defamation if the employer publicizes a false positive result, if the employer acts in bad faith and knew (or should have known) that the result was incorrect.

Contact an Attorney

If you think your employer drug tested you in violation of the law—for example, your employer's "random" drug tests weren't truly random—consider contacting an attorney to discuss your legal options.

And if you're a medical marijuana patient in Missouri and you were disciplined based solely on a positive drug test, you might have a legal claim against your employer. An attorney can advise you on the best way forward.

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