Tennant has been a substance abuse consultant for the California Department of Justice, the California Highway Patrol (where he taught officers how to recognize symptoms of drug use)[REF] and hundreds of private companies, including Texaco and the Southern Pacific Railroad [REF].
Tennant became involved with methadone clinics in 1972 when he became director of UCLA's methadone treatment program, later creating the nonprofit Community Health Projects, Inc. which operated 29 methadone facilities in California.