BACKGROUND: A truck driver was unloading wood chips from his open-top tractor-trailer unit via a movable floor unloading system on a mid-winter day in the Northeast. The trailer had a cross-stability bar centrally located at the top of the trailer. When using the movable floor unloading system to offload wood chips, these wood chips would routinely jam at the cross stability bar.
PERSONAL CHARACTERISTICS: The driver, in his late 40s, had been employed by the company for 10 years. He was considered experienced.
UNSAFE ACT OR CONDITION: The driver positioned the truck to unload the chips, unlocked and opened the trailer’s rear gate, and activated the movable floor unloading system. Witnesses observed the victim climb the exterior fixed ladder on the trailer and walk along the top edge of the trailer towards the rear of the trailer. This was reported as a common practice, especially when entering the trailer to clear chips jammed at the trailer’s cross stability bar. Although there were no witnesses after that point, it appears that the driver stepped from the top edge of the trailer onto the chip pile to clear the jam.
ACCIDENT: It appears that when the driver stepped on to the load, a void within the chip pile caused the pile to give way. The driver fell through, into the pile, and the chips engulfed and suffocated him. The movable floor unloading system continued operating, offloading the chips. Eventually the victim was offloaded from the trailer through the trailer’s rear gate along with the chips.
Approximately twenty minutes had gone by when the company owner and a co-worker realized that they had not seen the driver. The company owner went over to the trailer and noticed that the movable floor unloading system and the truck were still running. A pile of chips had accumulated on the ground and was now blocking the rear gate opening and preventing the remaining chips from being offloaded. The company owner then moved some chips from the top middle section of the pile and noticed the victim’s head.
The company owner turned off the movable floor unloading system and placed a call for emergency medical services. The local police arrived at the incident location within minutes and then placed calls to the local fire department and the medical examiner’s office. The driver was pronounced dead at the incident location.
INJURY: The medical examiner listed the cause of death as cardiac arrest due to compression asphyxia.
RECOMMENDATIONS FOR CORRECTION:
- Minimize load jamming by ensuring that chip trailers equipped with both cross stability bars and movable floor unloading systems are not loaded up to or above the cross stability bar.
- Provide employees frequent training on safe trailer loading, unloading, and jam clearing procedures.
- Develop, implement, and enforce a permit space program for permit-required confined spaces, such as loaded chip trailers (as OSHA requires).
- Ensure that trailers with movable floor unloading systems are either equipped with automatic sweeping tarps or that manual sweeping does not begin until after the entire trailer has been offloaded.
- Conduct routine hazard assessments of equipment and how tasks are completed to identify potential hazards to which workers are exposed.
Courtesy of the Forest Resources Association: https://www.forestresources.org/