We all know the electrical industry can be a pretty dangerous place. Fortunately, safety devices, such as audible alarms and sensors, and safety procedures like lockout/tagout can help prevent injuries and save lives — but only if they are properly maintained, repaired, and followed. Employees at a chrome-plated aluminum automobile wheel manufacturer learned this lesson the hard way when one of their coworkers, a 44-year old male electrician who had been with the company for 10 years, was crushed to death early one morning.
At the time of the incident, the facility’s wheel chrome plating process involved a three-dip procedure consisting of separate vats. A computer-controlled hoist moved the product through the stages of dipping and stopped for pre-programmed amounts of time in each vat. The hoist was equipped with a safety sensor device designed to stop the hoist if anything came in contact with the sensor.
At approximately 5:30 a.m., the victim entered the chrome plating area through an entrance in the middle of the tank area. The hoist operator stated he was not aware that the victim was on the walkway between the tanks. No witnesses saw the victim enter the chrome plating area, and none were present in the vicinity of the catwalk.
Based on information from coworkers, the victim most likely was leaning over the edge of the tank as the hoist passed him. Regrettably, the safety sensor on the hoist was not operational at the time. As the hoist automatically moved toward the man, instead of shutting off when it made contact with him, it continued on its path, pinning the electrician between the tank and the pipes on the rim of the tank. The hoist operator saw the man pinned, immediately shut the hoist off, and informed his supervisor, who called 911. Paramedics transported the victim to a local hospital where he underwent emergency surgery, but he was pronounced dead in the operating room. The official cause of death was listed as blunt force trauma.
To avoid similar tragedies, NIOSH recommends the following:
Employers should ensure moving machinery is inoperable when an employee accesses a danger zone.
In this case, the use of gate interlocks, visual or auditory warning alarms, or sensing devices that would stop the hoist whenever an employee entered the danger zone could have been used. As an alternative, a lockout/tagout procedure that would shut down hoist operation whenever an employee was required to enter the danger zone of crane operation could have been implemented.
Employers should ensure that emergency safety devices are maintained in operating condition.
Post-incident inspection of the hoist safety sensor revealed that the local tank atmosphere resulted in sensor corrosion, rendering the stop inoperable. Therefore, when the safety sensor device made contact with the victim, the crane failed to stop operation.
In addition, the employer did not perform routine inspection and maintenance of the hoist safety sensor device. There was no documentation that the device was tested or deemed operable by company maintenance personnel. It is not known if the victim or hoist operator knew the safety sensor device was inoperable. Had the safety sensor device on the hoist been inspected and repaired, the crane would have stopped when it made contact with the victim and ultimately prevented his death.
Reprinted with permission from the National Institute for Occupational Safety and Health (NIOSH), Division of Safety Research (DSR). All electrical-related FACE reports can be viewed in their entirety at www.cdc.gov/niosh/face/default.html.