The employer shall use every reasonable means and precaution to assure himself that each employe is mentally and physically qualified to perform his work in accordance with this subchapter, and that he is not addicted to the use of intoxicants and habit-forming drugs.
34 Pa. Code § 39.514
This section cited in 34 Pa. Code § 39.501 (relating to general requirements); and 34 Pa. Code § 39.511 (relating to distribution and enforcement of rules).