Flaming forklift badly burns warehouse co-workers
By Myron J. Boyajian, Contributing Writer
Determining an accident’s cause may only be the first step in providing both safe equipment and a safe work environment.
At a warehouse, incoming loads were removed and consolidated for local delivery. A supervisor temporarily operated a forklift for a dockman-trucker who left to deliver a rush order. About a half-hour into unloading, the foreman’s
co-workers heard a boom followed by a fireball, and then cries for help from the foreman, whose clothing was aflame.
Co-workers ran to help. One took off his own shirt to smother the flames and was also burned. The fire department and responders put out a few small fires and took the injured men to a hospital for burn care, with the foreman eventually needing skin grafts and reconstructive surgeries.
Both men filed suit against the forklift manufacturer and an independent service company. They in turn filed suit against the warehouse, alleging failure to properly train the forklift operators to check their trucks before operation. Retained to determine the cause of the accident, I traveled to the accident site to inspect and document the burned forklift.
It became quickly apparent that the LP fuel tank, mounted on a swinging bracket on top of the counterweight, had come loose, and the tank support bracket hit the trailer’s cargo door frame and, in turn, punctured the tank. The LP fuel gushed out, hit the hot truck exhaust system and ignited.
The actual cause of the fire was clear, but other issues blurred the case. Witnesses said the spring-loaded latch randomly opened, letting the tank swing loose. And perhaps the driver didn’t check the latch at the beginning of his shift before the foreman borrowed it, although the truck was used several hours without a loose tank.
To cut through the fog, I tried to determine what could prevent unlatching in the first place. My opinion report stated that gasoline and diesel-fueled forklifts have tanks typically hidden in secure locations protected from impact. In LP-fueled vehicles, the LP tank must be in a convenient place for removal for refueling — typically on top of a truck’s rear counterweight, but rigidly latched within the confines of the truck’s body and frame. But on this forklift mounting the LP tank on a latched, hinged bracket let the tank swing clear of the counterweight top to allow the driver’s seat/engine cover to be tilted backward between the rear overhead guard legs for engine access.
I made the argument that this swing-out bracket, convenient for maintenance, created a hazard by its exposure to impact. Since the swing-out bracket aids maintenance and is not likely to be eliminated by the manufacturer, I suggested a design that could prevent inadvertent opening and warn the driver that the bracket was open. The first was easy as I resurrected the manufacturer’s original patent design used for early production using a nut and a bolt to secure the tank bracket, but dropped in favor of the spring-loaded latch.
The second was to suggest the use of a microswitch to sense that the latch was open or closed and to light a warning lamp and cut off engine ignition if the tank bracket became unsecured. This sensing and warning system was already in use by a competitor of the forklift manufacturer in this case. I built a model of the latch with a sensor and warnings, and demonstrated it during my deposition in this case, which settled in favor of the injured workers.
This story has not ended, however. Swing-out brackets have gained popularity and the potential for serious operator injury and property damage may grow. The final chapter of this story will be my goal of seeing an industry standard developed that will provide safer operation of forklifts with movable LP tank systems.
Contributing Writer Myron J. Boyajian, P.E., is president of Engineering Consultants, a consulting service for forensic and design activities. This case is drawn from his files. You can reach him at firstname.lastname@example.org.