§40.25
If the applicant admits that he or she had a positive or a refusal to test result on a pre-employment test, the employer is not permitted to use the applicant to perform safety-sensitive duties until and unless the applicant documents successful completion of the return-to-duty process.
This Part 40 requirement applies whether or not the pre-employment positive or refusal occurred before, on, or after August 1, 2001.
Should no proof exist that the return-to-duty process was successfully complied with by the applicant, a current return-to-duty process must occur before the individual can again perform safety-sensitive functions.