The U.S. Department of Transportation’s (DOT) Office of Drug and Alcohol Policy Compliance has issued a Notice to address the recent passage of state initiatives purporting to legalize marijuana use for recreational purposes. The DOT requires testing of applicants and employees in safety-sensitive transportation positions for marijuana, cocaine, opiates, amphetamines, and phencyclidine. Applicants must be drug tested before they begin performing DOT-covered safety-sensitive duties, and employees must be drug tested in certain circumstances, including following an accident, randomly, and when reasonable suspicion of drug use exists. During that review process, the test subject is permitted to provide the medical review officer (MRO) with information that would explain the positive test result, such as a prescription. If the test subject provides a legitimate medical explanation for the confirmed positive test result, then the MRO will report the test result to the (prospective) employer as verified negative. If the test subject does not provide a legitimate medical explanation, he or she must be removed from safety-sensitive duties and referred to a substance abuse professional for evaluation. Applicants for and employees in safety-sensitive transportation positions will not be allowed to explain away a confirmed positive test for marijuana based on recreational or medical use purportedly authorized by state law.