Prohibitions on the abuse of drugs apply

Workplace drug and alcohol policies typically prohibit any inappropriate use of drugs or other substances that cause impairment (B), which can include illegal drugs, prescription drugs taken other than as prescribed, over-the-counter medications, alcohol, and even inhalants if they lead to impairment on the job. The prohibition is not limited to illegal and prescription drugs alone (A), only illegal drugs (C), or only misuse of prescription drugs (D), as impairment from any substance can create safety hazards. (Fundamentals of Crew Leadership, Fourth Edition, NCCER, Section 3.4.1 Understanding Substance Abuse in the Workplace)