illegal use of drugs
(B) Illegal use of drugs The term “illegal use of drugs” means the use of drugs, the possession or distribution of which is unlawful under the Controlled Substances Act [ 21 U.S.C. 801 et seq.]. Such term does not include the use of a drug taken under supervision by a licensed health care professional, or other uses authorized by the Controlled Substances Act or other provisions of Federal law.
Source
29 USC § 705(10)(B)
Scoping language
None identified, default scope is assumed to be this section only