29 CFR Part 1630, Regulations to Implement the Equal Employment Provisions of the ADA (Title I Regulations with amendments issued through May 2016)

(c) Drug testing—

(1) General policy. For purposes of this part, a test to determine the illegal use of drugs is not considered a medical examination. Thus, the administration of such drug tests by a covered entity to its job applicants or employees is not a violation of §1630.13 of this part. However, this part does not encourage, prohibit, or authorize a covered entity to conduct drug tests of job applicants or employees to determine the illegal use of drugs or to make employment decisions based on such test results.

(2) Transportation employees. This part does not encourage, prohibit, or authorize the otherwise lawful exercise by entities subject to the jurisdiction of the Department of Transportation of authority to:

(i) Test employees of entities in, and applicants for, positions involving safety sensitive duties for the illegal use of drugs or for on-duty impairment by alcohol; and

(ii) Remove from safety-sensitive positions persons who test positive for illegal use of drugs or on-duty impairment by alcohol pursuant to paragraph (c)(2)(i) of this section.

(3) Confidentiality. Any information regarding the medical condition or history of any employee or applicant obtained from a test to determine the illegal use of drugs, except information regarding the illegal use of drugs, is subject to the requirements of §1630.14(b) (2) and (3) of this part.