The drug and alcohol testing regulations require operators of gas, hazardous liquid and carbon dioxide pipelines, other than operators of master meter systems and liquefied natural gas (LNG) facilities to have anti-drug and alcohol misuse prevention programs applicable to persons who perform operating, maintenance, or emergency-response functions covered by the DOT pipeline safety regulations in 49 CFR Parts 192, 193 or 195, and to conduct drug and alcohol testing in accordance with the regulations. Drug testing under Part 199, Subpart A is to be conducted prior to employment, after an accident, randomly, upon reasonable cause, and upon the return to duty of an employee who fails or refuses a drug test conducted under Part 199. Alcohol testing under Part 199, Subpart B is to be conducted upon reasonable suspicion, upon the return to duty of an employee who fails or refuses an alcohol test conducted under Part 199.