Many occupational deaths and injuries occur when workers fail to lock out and block out machinery before working on it.  Electrocution injuries, severe crushing injuries or the loss of fingers, hands and arms can occur when machinery is

inadvertently started while it is being repaired or maintained.  Here are a few true stories.

          **Three men were doing maintenance inside an asphalt mixer.  One employee was still inside

              when the power was turned back on and the mixer starter.  He was instantly killed.

          **An employee turned off an air-operated valve he was working on, but did not disconnect and lock it out. 

              During the repair operation he slipped and inadvertently turned on the switch letting air into the valve.

              His hand was caught and crushed in the valve.

Lockout/blockout requires that any energy source (electrical, hydraulic, mechanical, compressed air, or any other source that might cause unexpected movement) must be disengaged or blocked.  Electrical sources must be de-energized and locked.  There is a difference between turning off a machine and actually disengaging a piece of equipment. 

When working on machinery, take these four steps to protect yourself from injury:

1.       De-energize the machine.  Positively disconnect it from the power source.  If there is more than one source of power, disconnect them all.

2.      Lock out the disconnect switches.  Every employee will have a lock and key for each disconnect before working on machinery.

3.      Tag the disconnect switches.

4.      Keep key with you or with your direct supervisor.  Locking devices and tags may be removed only by the employee who placed them.  Locking devices and tags shall be removed upon completion of the work and after installation of protective guards.

Each employee working on machinery must lock out and tag the power disconnect.  Never assume the machine you are working on has been disconnected and locked, unless you have done it yourself.

Accidents have also occurred when workers did take the necessary steps of disconnecting the main power source.  But they did not take a crucial step to complete this procedure.  Always test equipment to make sure the machinery is de-energized.