Last week (Drug testing and legalization, linked below) we raised the question: if marijuana use is legal in your state, is it legal or not legal for your employer to require drug tests for it, and to fire you for using? An astute reader pointed us toward some of the current answers, and the present answer is, it is probably legal--although if you work in Arizona or Delaware, probably not.
In Colorado, the Colorado Court of Appeals has ruled (for Dish Network against Brandon Coates) that even though Coates used marijuana under the state's medical marijuana use law, he could be terminated by the company for failing a drug test. The court determined that the state's "Lawful Off-Duty Activity Statue" did not cover use of marijuana, because it remains illegal under federal law. This is the intermediate level of the Colorado court system; an appeal has been made to the Colorado Supreme Court, but initial comments suggest that that court is inclined to uphold the Court of Appeals ruling.
Meanwhile, the Washington state Supreme Court, in Roe v. TeleTech Customer Care Mgmt. LLC, Dkt. 83768-6, ruled that the state's Medical Use of Marijuana Act ("MUMA") does not prevent employers from terminating employees who use the drug legally within the state. The Washington law specifically stated that it had no effect on employment situations. The court rejected a variety of claims in this case, including stating that a requirement to accommodate persons with disabilities specifically excludes any requirement that federal law be violated in the process.
Similar rulings have come out of state Supreme Courts in California (Ross v. RagingWire), Montana (Johnson v. Columbia Falls Aluminum Company), and Oregon (Emerald Steel Fabricators, Inc. v. Bureau of Labor & Industries), and from a Federal District Court in Michigan (Casias v. Wal-Mart Stores, Inc.). The U. S. Supreme Court recently refused to legalize marijuana use by court decree, putting the issue of federal regulation on Congress.
This is not universally the case. Laws in Arizona and Delaware specifically protect authorized medical marijuana users from employment discrimination, excepting impairment on the job or drug use policies necessary for compliance with federal law, such as defense contractors. Other states have less explicit laws which offer some protection to employees using marijuana under the direction of a physician, including Connecticut, Rhode Island, Maine, and possibly (in a new law) Illinois. In the main, however, it appears that your employer has the right to terminate you if you fail a test for marijuana use, even if it is legally authorized medical use in your state and there is no evidence that you were using it on the job--even in Colorado.