This is an excerpt from the article “Workplace Solutions: Lockout…”. For more information, please visit www.cdc.gov.
The NIOSH FACE program investigated the following incident in which a millwright was fatally injured because of an uncontrolled release of energy while he was repairing a debarker [NIOSH 2006]:
The teeth on the debarker feed rolls had become worn, and the worker had been assigned to weld additional metal to build up the feed roll teeth. He had not conducted this type of repair before.
To safely de-energize this machine, six electrical sources and one pneumatic energy source needed to be disconnected and locked out, and the pressure in the air line that automatically controls the up and down motion of the feed rolls needed to be bled off. The victim disconnected and locked out two of the electrical sources (See Figure 1), but he did not disconnect and lock out the other four electrical sources or the pneumatic energy source, and he did not bleed off the pressure in the air lines. In this condition, the machine’s automatic control system remained energized. As the victim welded metal to the feed roll teeth, he leaned forward and placed his head between the feed rolls to reach areas that required more metal. The feed rolls automatically cycled, and closed over his head.
His supervisor had left to check on another machine and when he returned, he found the millwright caught in the machine. Emergency medical services personnel arrived 20 minutes after receiving the 911 call and attempted cardiopulmonary resuscitation, but the millwright had died.
The millwright had been trained in general lockout/tagout procedures on the job, but the procedures failed to address the following:
- The use of locks to ensure that the electrical sources remain disconnected.
- The disconnect locations for the six electrical energy sources and one pneumatic energy source for the debarker.
- Procedures for bleeding, blocking, and verifying that stored pneumatic energy (air pressure) had been rendered safe.
- Clearly labeling each lock with a durable tag (or durable label or marking) to identify the worker assigned to a lock that is used to secure an energy control device.
NIOSH recommends that employers and workers take the following steps to prevent machine-related injuries:
NIOSH recommends that employers comply with the OSHA regulations outlined in 29 CFR* 1910.147, the control of hazardous energy (lockout/tagout). Results of NIOSH fatality investigations indicate that the following steps are particularly important.
- Develop and implement a written hazardous energy control program, including lockout/tagout procedures, employee training, and inspections before any maintenance or service work is done [NIOSH 1999].
- Be sure that workers have a clear understanding of when hazardous energy control procedures apply and training on how to properly apply the procedures.
- Ensure that procedures on lockout/tagout are developed that are specific to each machine [NIOSH 2006; Michalscheck 2008].
- Provide training to production workers in addition to maintenance workers in methods of energy isolation and control [see 29 CFR 1910.147(b)].
- To effectively isolate each energy source, ensure that workers are provided with a sufficient number of lockouts and tagouts and other hardware that may be needed [See 29 CFR 1910.147(c)(5)(i)].
- Clearly label isolation devices, such as breaker panels and control valves [NIOSH 1999].
- After removing the lockout or tagout devices but before starting the machine, be sure that all employees who operate or work with the machine, as well as those in the area where service or maintenance is performed, know that the devices have been removed and that the machine is capable of being re-energized [OSHA 2002; 29 CFR Part 1910.147 (e)(3)].
- Ensure that no one under the age of 18 works on machinery declared hazardous in the Child Labor Rules [29 CFR 570.120].
- Ensure that workers receive training in their primary language.
- Follow the regulations contained in your employer’s hazardous energy control program.
- Complete all employer-provided training on hazardous energy control procedures.
- Before beginning machine adjustment, maintenance, or servicing work, do the following [NIOSH 1999]:
1. De-energize all sources of hazardous energy:
– Disconnect or shut down engines or motors.
– De-energize electrical circuits.
– Block fluid (gas or liquid) flow in hydraulic or pneumatic systems.
– Block machine parts against motion.
2. Lockout and tagout all forms of hazardous energy, including electrical breaker panels and control
3. Block or dissipate stored energy:
– Discharge capacitors.
– Release or block springs that are under compression or tension.
– Vent fluids from pressure vessels, tanks, or accumulators, but never vent toxic, flammable, or
explosive substances directly into the atmosphere.
- Make sure that only one key exists for each of your assigned locks and that only you hold that key.
- Verify by test and/or observation that all energy sources are de-energized.
- Inspect repair work before removing your lock and activating the equipment.
- Make sure that only you remove your assigned lock.
- Make sure that you and your coworkers are clear of danger points before re-energizing the system (see 29 CFR 1910.147(e) and 29 CFR 1910.117(f).
Consider designing equipment that requires fewer and more easily accessible disconnect points to facilitate the use of safe lockout/tagout procedures for maintenance and repair [NIOSH 2006].