The OSHA lock-out procedure is a system designed to keep workers safe while performing maintenance or other work on machinery. The idea is to prevent the accidental release of energy while anyone is near a machine's dangerous moving parts.

When there are a lot of people around working on different things, communication tends to break down. The electricians might not know what the millwrights are doing, the operators don't know what the engineers are up to, and management doesn't have a clue. Sometimes work continues for more than one shift, and responsibility has to be transfered to another person. The last thing someone wants when he's cleaning out the hydropulper is his coworker pressing the start button because he doesn't know he's in there.

Everyone working on a piece of equipment must follow the lock-out procedure

  1. Identify the types of energy sources used, potential hazards, and all control devices. Some machines have multiple energy sources, such as electricity, compressed air, hydraulics, and gravitational potential energy. Make sure you have identified all the sources of power. To verify the correct control devices, test the machinery by starting it briefly. Shutting off the wrong control device doesn't help anyone.

  2. Notify all affected employees that you will be locking out the equipment. This means anyone else who will be working on it, anyone who might want to try turning it on, and the manager in charge of the area. Communication is important.

  3. Turn off all operating controls and properly shut down the machine.

  4. Isolate all energy sources that you identified in Step 1. Pull electrical disconnect switches or fuses as appropriate, bleed and vent hydraulic pressure and compressed air, relax springs or secure them in position, and set blocks under anything that might fall (such as a 100-Ton Press).

  5. Lock-out the system. Put a lock with your name on it on every source of power you isolated. This means that you accept responsibility for your own safety. No one is allowed to remove your lock except for you, except as noted below.

  6. Test the controls. Make sure the machine is dead by pressing the start button. This is the step that is most often skipped, but it is the most important. You want to make sure you locked out the correct power sources. Even if you are familiar with the machine or have worked on it before, the power source may have been changed since you last worked with it. Return all controls to the off position when finished, so it does not start back up unexpectedly when you remove your lock.

  7. Perform the work safely and to the best of your ability. Leave your lock on the power sources until you are finished.

  8. Once the work is complete, the equipment has been put back into operating condition, all guards have been replaced, you have cleaned up your tools and the work area, and you have notified all affected employees, remove your lock and only your lock. The last person to remove his lock accepts responsibility that the machine is ready to operate.

Never put yourself in the way of a machine's moving parts without following every step in the above procedure. OSHA's lock-out procedure saves over a hundred lives and prevents thousands of injuries every year by ensuring equipment is safe to work on. Many companies have severe penalties for ignoring the lock-out procedure, including dismissal.

Occasionally, a worker will leave for the day without removing his lock. If the machine is needed, contact the employee so he can return and remove his lock. If he cannot be contacted, his supervisor is to take every precaution available to make sure the machine really is safe to be put back into operation, and then remove the lock. This usually means contacting everyone else who worked on the machine and carefully inspecting that it is back in working condition. Whenever a supervisor has to remove an employee's lock, written documentation of the event must be kept and the employee should be subject to disciplinary action.