On Monday, employers were provided guidance on an issue of increasing interest: whether an employee’s off-duty marijuana use that is lawful under state law can serve as grounds for termination. In Coats v. Dish Network, Case No. 13SC394, the Colorado Supreme Court held that employers may fire employees who test positive for marijuana, even if those employees are registered and lawful medical marijuana users under state law.

Brandon Coats was employed by Dish Network as a customer service representative. He is a quadriplegic medical marijuana patient who smoked marijuana in the evenings after work. During a random drug test at work, Coats tested positive for marijuana and his employment was terminated. Dish Network did not allege that Coats used marijuana while on company premises or that Coats was impaired while at work; however, under the company’s zero-tolerance program, any detectable amount of drug in the employee’s system is grounds for disciplinary action, up to and including termination.

Under Colorado law, medical and recreational marijuana use is legal. Under federal law, however, marijuana use remains unlawful. Coats challenged his termination under Colorado’s “lawful activities statute,” that makes it an unfair and discriminatory practice to discharge an employee based on that employee’s lawful activities outside of work. The Colorado Supreme Court determined that “lawful activities” referenced in the Colorado statute are only those that are lawful under both state and federal law. As marijuana is considered an illegal substance under federal law, employers are within their rights to terminate employees who test positive for marijuana, even if those employees use marijuana under a valid state medical marijuana license.

Over 20 states and the District of Columbia have legalized medical marijuana, and this decision is further support for employers to enforce their zero-tolerance drug policies.