28 CFR 35.131 - Illegal use of drugs.
(1) Except as provided in paragraph (b) of this section, this part does not prohibit discrimination against an individual based on that individual's current illegal use of drugs.
(2) A public entity shall not discriminate on the basis of illegal use of drugs against an individual who is not engaging in current illegal use of drugs and who -
(i) Has successfully completed a supervised drug rehabilitation program or has otherwise been rehabilitated successfully;
(ii) Is participating in a supervised rehabilitation program; or
(iii) Is erroneously regarded as engaging in such use.
(b) Health and drug rehabilitation services.
(1) A public entity shall not deny health services, or services provided in connection with drug rehabilitation, to an individual on the basis of that individual's current illegal use of drugs, if the individual is otherwise entitled to such services.
(2) A drug rehabilitation or treatment program may deny participation to individuals who engage in illegal use of drugs while they are in the program.
(c) Drug testing.
(1) This part does not prohibit a public entity from adopting or administering reasonable policies or procedures, including but not limited to drug testing, designed to ensure that an individual who formerly engaged in the illegal use of drugs is not now engaging in current illegal use of drugs.
(2) Nothing in paragraph (c) of this section shall be construed to encourage, prohibit, restrict, or authorize the conduct of testing for the illegal use of drugs.