(a) Steam cleaning units used underground shall be only electrically operated. Their use shall be confined to repair shops where ventilation shall be arranged to conduct their exhaust to return air with baffles installed to prevent distribution of oil and grease in the return airway.

(b) Machines shall be equipped with a pressure relief valve and a soft plug. Cutoff valves shall not be installed in the discharge nozzle.

(c) The area in which the machine is used shall be cleaned after each operation. Oil, grease and other residue shall be put in metal containers and removed from the mine.

(d) Steam cleaner operators shall be provided with a protective mask when chemical and detergent solvents are used.