A clear decision has been made by Washington's Supreme Court, and the end result is that the state's Medical Use of Marijuana Act does not protect employee medical marijuana use.
In addition to siding with employer drug policies, the court made another interesting statement:
The state's Human Rights Commission, which is charged with investigating workplace discrimination, has no authority to investigate cases involving medical marijuana.
Passed by voters in 1998, Washington's Medical Use of Marijuana Act permits patients to utilize medical marijuana. While the law permits employers to ban employee medical marijuana use on-site, it is silent as to whether they can punish employees for use off-site.
The plaintiff in this case, a medical marijuana user fired for failing a drug test, argued that the law implies protection for employees who use medical marijuana off-site so long as it doesn't impair their performance. To say otherwise would be contrary to voter intentions.
The court didn't agree, citing the fact that medical marijuana use is illegal under federal law. It is contrary to public policy to "require an employer to allow an employee to engage in illegal activity."
The court also noted that, because medical marijuana use is a federal crime, it cannot form the basis of a reasonable accommodation claim under discrimination law. Therefore, state authorities have no jurisdiction over cases that involve employee medical marijuana use.
The overall effect of this opinion is quite simple:
As an employee, medical marijuana users have little to no recourse if fired within the state of Washington. Not under the Medical Use of Marijuana Act, nor under employment discrimination law.