Okla. Stat. tit. 40, § 502
The provisions of Sections 11 through 14 of this act shall not apply when the restriction on smoking relates to a bona fide occupational requirement or an applicable collective bargaining agreement which prohibits or allows off-duty use of tobacco products.
Laws 1991, HB 1590, c. 172, § 13, emerg. eff. May 8, 1991.