On June 15, 2015, the Colorado Supreme Court affirmed an appeals court decision ruling that employers can lawfully fire employees for use of medical marijuana.

Brandon Coats, a quadriplegic medical marijuana user and Colorado resident, sued his employer (Dish Network) for wrongful discharge after it fired him for testing positive for marijuana during a random drug test. Colorado law prohibits employers from discharging an employee for engaging in a “lawful activity” conducted off premises and during nonworking hours. Coats argued that because his marijuana use was lawful under Colorado’s medical marijuana law, he could not be terminated for that use. Dish Network countered that Coats’ marijuana use was not a “lawful activity” under the Colorado statute because medical marijuana, although legal in Colorado, remains prohibited by federal law. The trial court sided with Dish Network and dismissed Coats’ claim. The court of appeals affirmed, and Colorado’s highest court agreed, explaining that “any activity such as medical marijuana use that is unlawful under federal law is not a ‘lawful’ activity” under the Colorado statute.

This decision appears to follow the trend of federal court rulings on employees’ drug use. The Sixth Circuit concluded in 2012 that Wal-Mart’s discharge of an employee who violated its drug use policy was lawful, even though the employee’s medical marijuana use was permitted under the Michigan Medical Marijuana Act. Similarly, the Ninth Circuit held in 2012 that the Americans with Disabilities Act does not protect medical marijuana use, even though such use is permissible under California law.

Although the U.S. is becoming increasingly pot-friendly as legalization continues state-by-state, employers and employees are reminded that the federal Controlled Substances Act is still valid law and quite the big stick in employment cases.