If a large leak of refrigerant occurs, such as from a filled cylinder in an enclosed area, what action should be taken when no self-contained breathing apparatus is available?

a) Use butyl-lined gloves and try to stop the leak.
b) Use a leak detector to locate the leak and try to stop the leak.
c) Vacate and naturally ventilate the area.
d) Make sure the unit is de-energized, close the service valves, and try to stop the leak.

C. In the event of a large refrigerant leak in an enclosed area and no self-contained breathing apparatus is available, the safest action is to vacate and naturally ventilate the area. This prevents exposure to potentially harmful refrigerants. Ensuring safety should always be the primary concern.

If a large leak of refrigerant occurs from a filled cylinder in an enclosed area and no self-contained breathing apparatus is available, the best course of action is to vacate and naturally ventilate the area (option c). This ensures the safety of all individuals by avoiding exposure to potentially harmful refrigerants.

Taking other actions such as trying to stop the leak without appropriate breathing apparatus or protective equipment can be dangerous. Always prioritize safety by evacuating the area and allowing for natural ventilation before attempting any further steps or repairs.