Colorado's Supreme Court ruled Monday that employers do not violate the constitution if they fire workers found to have used marijuana for medical reasons off-duty, despite the drug being recreationally legal in the state.

In the case, justices sided with Dish Network, who fired a quadriplegic employee named Brandon Coats in 2010 for failing a company drug test for marijuana. The company said that even though he had a doctor's note to use the drug, Coats violated Dish's zero-tolerance drug policy, which cites the fact that marijuana in any application is still illegal on the federal level. Medical marijuana has been legal in Colorado since 2000.

Coats contended that he had never used the drug or been under its influence while at work, which the company acknowledges. Colorado protects employees from termination for "lawful activities," but the court ruled the law applies only to activities which are legal under both state and federal law, CNN Money reports.

"Therefore, employees who engage in an activity such as medical marijuana use that is permitted by state law but unlawful under federal law are not protected by the statute," justices wrote.

Colorado also allows its businesses to prohibit their employees from using marijuana, even though the drug is effectively treated like beer or liquor under state laws.

Marijuana advocates say the court's decision strikes a dissonant precedent for the millions of Americans who legally use medical marijuana to treat symptoms––as well as a growing number who legally use it recreationally––but face severe punishments in their workplaces even for using it outside of work.

"This unfortunate ruling shows that even when we successfully remove the threat of criminalization for marijuana users, our movement still has a lot of work to do to erase instances of life-damaging discrimination that still exist in the private sector," Tom Angell, chairman of the Marijuana Majority, told ATTN:.

"Of course employers have a right to make sure workers aren't intoxicated on the job, but it should be none of their damn business if people imbibe on their own time and it doesn't impact their workplace productivity," he said.