After a DOT drug or alcohol violation, an employee may not perform safety-sensitive functions for any DOT employer until completing the return-to-duty process (49 CFR 40.305):

1. Evaluation by a SAP.
2. The education and/or treatment the SAP recommends.
3. A follow-up evaluation in which the SAP confirms compliance.
4. A negative return-to-duty test (directly observed for drugs; below 0.02 for alcohol).
5. Follow-up testing as set by the SAP.

The employer decides whether to return the employee to duty; completing the process makes the employee eligible but does not guarantee the job. For CDL drivers, each step is also reported to the Clearinghouse.