At last count, 14 states have adopted laws legalizing use of medical marijuana. Some employers in those states have expressed concerns over workplace safety and productivity issues arising from employee use of legal marijuana. These employers fear that if they take disciplinary action against an employee with a valid marijuana prescription, they could be subject to wrongful discharge or failure to accommodate disability discrimination claims.

Last month, the Oregon Supreme Court held that employers have no accommodation obligation for medical marijuana users despite that state's legalization of such use. The court concluded that the federal Controlled Substances Act gives employers the ability to exclude marijuana users from the workplace regardless of the reason for such use. Lower courts in other states with legalized medical marijuana have issued similar rulings.

A number of other states' medical marijuana laws explicitly prohibit employers from taking action against prescribed employees who test positive for marijuana, assuming there is no evidence of use at work, and if the employees are not subject to DOT or other federal testing requirements. No appellate court decisions have yet interpreted the interplay of these laws with federal prohibitions on marijuana possession and use.

Employers with operations in states that have legalized medical marijuana should monitor these developments, and tailor their drug testing and use policies to meet each states' interpretation of their laws.