Mandatory alcohol and drug testing is required by the United States Department of Transportation for some occupations and industries. This mandatory testing includes trucking, aviation, maritime, pipeline, railroad, and transit employees in safety-sensitive occupations. A safety-sensitive employee in the transportation industry is an individual who provides a safe work and transportation environment for co-workers and the traveling public.
The legal limit for being considered impaired by alcohol while driving is .08. However, the blood alcohol concentration that is considered impaired is a lower number than the standard driving BAC. The United States Department of Transportation regulations mandate that a .04 a positive alcohol test requires removal of an employee from driving or other safety-sensitive tasks.