Missouri Employers Beware: Employment Protections Under Constitutional Amendment 3

Date   Dec 15, 2022

On November 8, 2022, Missouri voters passed Constitutional Amendment 3 (the “Amendment”), which made limited marijuana use lawful in the State of Missouri for persons over the age of 21.  The Amendment took effect December 8, and as a result, persons over the age of 21 may purchase and possess up to three (3) ounces of marijuana, and may grow a limited number of plants if registered with the Missouri Department of Health and Senior Services for cultivation of marijuana plants.  In addition, the Amendment provides for expungement of certain marijuana-related offenses and provides a mechanism for persons incarcerated to petition the sentencing court to vacate the conviction.

For Missouri employers, the most critical provision is the prohibition on discrimination against persons who are medical marijuana qualifying patients.  Unless an employer would lose monetary benefits or a licensing-related benefit under federal law, an employer cannot discriminate in hiring or any aspect of employment or otherwise penalize a person based on their status as a qualifying patient or primary caregiver with a valid identification card.  This prohibition includes a bar to discrimination based on the person’s legal use of a lawful medical marijuana product off the employer’s premises during non-working hours, unless the person is “under the influence” of medical marijuana on the employer’s premises or during the hours of employment.  An employer cannot discriminate against a cardholder based on a positive marijuana drug screen, unless the person used, possessed marijuana, or was “under the influence” at the place of employment, or during the person’s working hours.

However, the restrictions above do not apply to an employee in a position in which legal use of lawful medical marijuana affects a person’s ability to perform job-related employment responsibilities, the safety of others, or conflicts with a bona fide occupational qualification reasonably related to the person’s employment.

Key Takeaways: 

  • The Amendment does not affect an employer’s ability to test for drugs (to include marijuana) so long as the testing program is not administered in such a way as to discriminate against medical marijuana cardholders.
  • The Amendment does limit an employer’s right to discharge an employee based on a positive marijuana drug screen, but only if the employee is a Medical Marijuana Qualifying Patient; thus, recreational users have no statutory protection.
  • Changes are likely needed to current drug testing policies as “illegal drugs” no longer covers marijuana as it is “legal” in Missouri; policies should be amended to specifically mention marijuana for employers who want to continue testing for THC.    
  • “Under the influence of marijuana” has no legal definition and there is no definitive test that will indicate whether a person is “under the influence.”  Until further guidance is possible from case law or otherwise, employers should use caution before carrying out disciplinary action against a qualifying patient based on a positive test for the presence of marijuana.

If you have any questions regarding this Alert, or other issues regarding Amendment 3 or marijuana use in Missouri, please contact the authors, Karen Milner, partner in our St. Louis office at, or Daniel Cardno, Associate in our St. Louis office, at Of course, you can also contact the FordHarrison attorney with whom you usually work.