Drug Testing, Alcohol Testing, and the ADA
"Although most laws concerning drug testing are at the state level, federal law must be considered when employers do test for ethanol (i.e., alcohol). The Americans with Disabilities Act (ADA) (Pub. L. No. 101-336) protects individuals with disabilities from discrimination in the workplace. Individuals with current alcohol-induced impairments and past alcohol problems are covered under the ADA. Thus, applicants cannot be tested or questioned about alcohol-use disorders until after a job offer has been made, and, even then, the law restricts when and under what conditions employees can be tested for alcohol use and other alcohol-use disorders. Moreover, employment decisions, particularly negative ones, cannot be based on these test results unless the employer can establish impairment caused by alcohol use (Hartwell, Steele, and Rodman, 1998). On the other hand, use of illegal drugs and of prescribed drugs used illegally and the drug-use disorders associated with such use are not covered under the ADA."
Ramchand, Rajeev; Pomeroy, Amanda; Arkes, Jeremy, "The Effects of Substance Use on Workplace Injuries" Center for Health and Safety in the Workplace (Santa Monica, CA: RAND Corporation, 2009), p. 27.