Federal Rules Allowing or Mandating Drug Testing
"The federal government does not impose rules regulating or prohibiting testing in the private sector and instead gives direct governance to specific agencies for employees under their jurisdictions and to the states. Two federal departments (Department of Transportation and Department of Defense) require random drug testing for contractors and employees holding certain jobs and in certain circumstances (e.g., after an accident). In addition, there is a federal law (the Omnibus Transportation Employee Testing Act, Pub. L. No. 102-143) that requires testing for specific types of transit operators. For private industries, state laws cover drug testing for both job applicants and employees. The details of laws across states vary: Random testing may be explicitly prohibited but may also be required for certain jobs, such as school-bus drivers. Some states also have conditions detailing the confidentiality afforded to test results or the policies and procedures for conducting such tests (ACLU, 2000)."
Ramchand, Rajeev; Pomeroy, Amanda; Arkes, Jeremy, "The Effects of Substance Use on Workplace Injuries" (Santa Monica, CA: RAND Corporation, Center for Health and Safety in the Workplace, 2009), pp. 26-27.