Safety Issues



The Truck Driver

A 60-year-old construction company trucking operations supervisor was crushed while assisting a truck driver coupling a belly dump trailer to his truck when the trailer shifted. The victim was an experienced truck driver and a trucking supervisor who had been with his employer, a heavy civil construction company, for 27 years.


The Incident 

On a rainy January day shortly before 7 a.m., he was assisting a company truck driver who was unable to raise the landing legs of his belly dump trailer, also known as a bottom dump trailer. The driver had driven trucks for 34 years, but this was his first day pulling a belly dump trailer and he was unfamiliar with its operational features.

The landing legs supported the weight of the trailer on the pavement and needed to be raised for the truck to be able to couple with the trailer properly. The driver unsuccessfully attempted to pull the pin locking the legs in the down position. He had backed his truck toward the trailer and heard a sound that he believed indicated that the truck’s 5th wheel’s jaws had closed and locked onto the belly dump trailer’s kingpin, but he did not visually confirm the coupling had occurred.

The victim determined that the truck’s back was not elevated high enough to relieve the weight of the trailer so that the safety pins could be removed and the landing legs raised. He placed boards behind the truck’s rear tires with the intention of having the truck back onto the boards to raise it.

The victim was standing towards the rear of the truck in a narrow space between two trailers where the driver could not clearly see him. He told the driver to unlock the 5th wheel slide, which he did from the cab. He then told him to move the truck forward to allow the truck some movement before backing onto the boards.

As the truck moved forward, the kingpin, which was not properly secured, came loose from the 5th wheel jaws and slid across the 5th wheel plate, causing the trailer to shift sideways, crushing the victim between the fenders of the two belly dump trailers. 




Drivers should visually confirm that the 5th wheel closes and locks on to the trailer’s king pin.

Develop and implement written safety procedures for connecting belly dump trailers that reflect the operator’s manual and established best practices.

Ensure that drivers are familiar with and know how to use the specific operational features of the trucks and trailers to which they are assigned; if they are not, then train them and observe that they are able to use them. 

Never work between closely parked trucks and trailers.

When performing duties outside of trucks, always wear an ANSI class 2 or 3 high-visibility safety vest or other safety apparel.

Washington State Department of Labor & Industries

Safety and Health Assessment and Research for Prevention (SHARP)

PO Box 44330

Olympia, WA 98504-4330


Safety Issues is presented by the National Institute for Occupational Safety and Health (NIOSH) in partnership with the National Truckers Association (NTA), with major contributions from State partners funded by NIOSH through the Fatality Assessment and Control Evaluation (FACE) Program.  The goal of the FACE Program is to prevent occupational fatalities across the nation by identifying and investigating work situations at high risk for injury and then developing and disseminating prevention strategies to those who can intervene in the workplace. State partners who contribute Safety Issues postings based on recent investigative reports are California, Iowa, Kentucky, Massachusetts, Michigan, New York, Oregon, New Jersey, and Washington.

The full report of this incident can be found at

The Safety Issues and Investigation Reports which are the products of NIOSH Cooperative State partners are presented here in their original unedited form from the states. They are intended for educational purposes only. The findings and conclusions in each report are those of the individual Cooperative State partner and do not necessarily reflect the views or policy of the NIOSH.

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