The Department of Transportation (DOT) requires employers to have a 2-Year Drug & Alcohol History Check on file for safety-sensitive employees under 49 CFR part 40.25, with the exception of pilots subject to the Pilot Records Improvement Act (PRIA). PRIA requires a 5-Year Drug & Alcohol History Check.

The 2-Year Drug & Alcohol History Check shows if an applicant or employee has tested positive on a drug or alcohol test administered by a DOT-regulated employer. The results of the check would prompt the operator to see if a Return-to-Duty and Follow-Up testing is necessary.