In a closely watched case involving legal protections for medical marijuana users, the Colorado Supreme Court decided yesterday that the state’s “lawful products” statute does not apply to activities that violate federal law.

Medical marijuana use is legal in Colorado, but because marijuana is still an illegal drug under federal law, the Court found that Plaintiff Brandon Coats was lawfully discharged by Dish Network after he tested positive for marijuana.

Mr. Coats has been a medical marijuana user since 2010, when he discovered that marijuana helped calm violent seizures and muscle spasms caused by injuries received in an accident that he’d had as a teenager. After he failed a cheek-swab random drug test in 2010, Dish Network terminated him under its zero-tolerance policy.

Mr. Coats sued for wrongful termination, contending that his termination violated the state’s protections for employees who engage in “legal activities” during non-working hours.

In yesterday’s decision, the state Supreme Court said that it was not a violation of the Colorado “lawful activities” statute for an employer to take action against an employee for violating federal law. The Court affirmed a lower court decision that had reached the same result.

Colorado is one of about 30 states that have laws protecting employees from discrimination based on their engaging in lawful activities or using lawful products during non-working hours. The original intent of these laws was primarily to protect tobacco users from discrimination.

Use of medical marijuana has been legal in Colorado since 2000, when voters approved an amendment to the state constitution. The Colorado law specifically provides that employers do not have to “accommodate” medical marijuana use. (Recreational marijuana use has been legal since 2012.)

Similarly, the supreme courts in California, Montana, and Washington state have held that employers are not required to make reasonable accommodations to users of medical marijuana because it is still illegal under federal law.

Roughly 25 states and the District of Columbia now have medical marijuana laws, and a few states – including Arizona, Delaware, Minnesota, Nevada, New York, and Rhode Island – also protect holders of medical marijuana cards from discrimination.

Employers should stay abreast of the ever-changing legal landscape in this area, whether they’re in “medical marijuana” states or not. And if you’re in a medical marijuana state, be sure that your substance abuse policies provide you with maximum protection to ensure the safety of your workplace and the public, but without violating applicable state laws.