NO! OSHA clearly specifies a 1 padlock 1 key system to maintain the integrity of the program and ensure the safety of the worker. A 1 key system gives the worker complete control over the energy source and prevents accidental or un-authorized access by others. In the event of key loss the padlock has to be destroyed. Having a Master Key negates the system and could lead to a catastrophe if the key is used by an unauthorized person.
Master Keyed padlocks are quite popular in several countries for various reasons, viz: to control specific groups of locks by supervisors and prevent lock destruction in the event of key loss. When Master Keyed padlocks are employed in any organization, the responsibility lies with the supervisor or manager to secure the keys in a proper location and prevent unauthorized access.