This subchapter shall not be interpreted to apply to the use of toxic inhalants, or the condition produced by the use of such substances, where the use is made, and condition produced by or under the express direction or written prescription of a licensed physician for medical purposes, or is necessarily incident to employment, or is necessary to effectuate a legitimate purpose or activity. This is an affirmative defense which must be pleaded and proved by the defendant.
(Ord. 306, passed 9-14-1987)