For: 1994-2002 Dodge Cummins 5.9L - Manual Switch PowerHalt: Air Intake Emergency Shut-Off Valves Many work environments where diesel engines are used have a possibility of exposing the engine to combustible vapors. Emergency shut-off valves are used to comply with safety regulations and directives enforced by both industry and government agencies. These agencies require air intake shut-off valves in all hazardous work areas, as well as an alternative safety option for diesel engine shut-down. Using an emergency shut-off valve prevents diesel engine runaway and protects against catastrophic damage to equipment, facilities and personnel when a runaway condition occurs.