By Amy Materson
The accident: A truck driver was unloading wood chip material from his open-top trailer via a moveable floor conveyor unit. During the unloading process, the load became jammed, and the driver climbed to the top of the trailer to clear the obstruction. The load gave way as the driver stepped onto it, engulfing him in the material. He was pronounced dead at the scene from cardiac arrest due to compression asphyxia.
The bottom line: A post-accident investigation determined the trailer was equipped with a cross stability bar at the top of the trailer which would cause loads to jam if the trailer was overfilled. The investigation found the trailer had been loaded with material all the way to the bar, requiring someone to enter the confined space of the trailer to clear the jam manually. Also, employees would routinely climb into the trailer to sweep the unit’s floor before the unloading operation was complete.
Know your equipment
Moveable floor systems are more suitable for heavier trailers designed without cross stability bars, which allow the load to flow continuously from the rear of the trailer with no obstructions. If you find your trailer is equipped with both a conveyor floor and a cross stability bar, you must not load the trailer up to or above the bar. Also, if your trailer is equipped with a moveable floor system, ask if the trailer has automatic sweeping tarps installed. If not, never begin sweeping the trailer’s floor until unloading is complete.
Know the situation
A trailer with a full load may be identified as a permit-required confined space, and requires development of a permit safety program. Your employer is required to provide safety measures such as ensuring an attendant is stationed outside the space while you enter the trailer, among other requirements.
Know the procedure
Your employer will have a training program on loading, unloading and clearing jammed loads from the trailer. You should undergo annual training, which should be updated to include hazards defined during hazard assessments as well as any new procedures to be implemented.
Information for this Safety Watch is taken from an accident report and from the Center for Disease Control’s NIOSH Fatality Assessment and Control Evaluation Program. It is for general information only.