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During the administration of President Ronald Reagan, there was a national focus on drug use in the United States and the President issued an executive order on September 15, 1986 to allow the Health and Human Services to certify laboratories and begin testing Federal employees.
In 1985 there were two New York subway accidents with fatalities, where the operators were found to have been using Marijuana. In 1987 there was a railroad accident involving an Amtrak train and Conrail train in which two Conrail engineers were found to be using Marijuana. In this accident, 16 people were killed and 170 injured.
In 1988, the Department of Transportation published the first rule for workplace drug testing
regulations, which is found in 49 CFR Part 40. Alcohol testing was added in 1994. Part 40 is the source for information on drug and alcohol testing in the DOT – regulated industry.
In 2000, the DOT rewrote Part 40 into current plain language format. On May 2, 2023, oral fluid testing was added as an alternative to urine testing.