Employer implementation of mandatory drug testing in a unionized environment raises significant legal issues apart from the legality of the testing measures themselves. Often, the contemplated testing measures will so affect terms and conditions of employment as to require collective bargaining prior to implementation. The duty to bargain extends not only to the decision whether to institute drug testing, but also to the particulars of testing procedures, purposes for which test results will be used, and severity of discipline for positive results or refusal to submit. The unionized environment also provides a benefit to employers in addition to the potential burden imposed by the duty to bargain. Employees' drug testing-related State law claims against employers will often be preempted by Federal law and resolved not in the courts, but through the less formal and less risky contractual grievance and arbitration procedures. These claims include wrongful discharge suits brought by employees discharged for failure to submit to testing or on the basis of positive test results, and emotional distress claims relating to wrongful discharge. 44 notes. (Author abstract modified)