An employee of an interstate moving company reported he observed to co-workers smoking marijuana in a hotel room while the team was on the road. He reported it to his manager, who in turn confronted the co-workers with the accusation. The co-workers denied the charge. The complainant announced he was quitting because he couldn't work with substance abusers who could jeopardize his safety. He picked up his pay check late last week and said he was going to sue.
Federal law requires interstate truck drivers to be drug free.
The employer is required to investigate charges of drug use impartially. In this case, you had one person's word against two. The two co-workers had a motive to deny using marijuana. Although not permissible in many industries, in interstate trucking drug testing is encouraged, and in some cases mandated by federal law. Your failure to give a drug test would seem to call into question the validity of the investigation.