Fatality Assessment and Control Evaluation (FACE) Program
Worker Falls to His Death in a Telescoping Boom Forklift Overturn
During the summer of 2003, a 19-year-old construction worker died after falling 30 ft. (9 m) from the forks of a telescoping boom forklift. He was member of a five-man crew hired by a local greenhouse company to dismantle and relocate a large old barn. The company owner rented the forklift from a local rental service, where he received training in the basic operations of the machine. The owner’s adult son was operating the forklift at the time of the incident. It was positioned partially on a driveway on the west side of the barn. The right wheels were on the driveway ramp and the left wheels were at a lower elevation on grass. The frame leveling control was set at its maximum position (12 degrees) to compensate for the sloping ground. The crew was removing the second rafter section that morning, taking apart joints and lowering sections to the ground. The victim was on the ground and rode up on the forks of the forklift, attaching the rafter to the forks with nylon straps, one strap to each fork. The operator then raised the rafter section up off the barn, with the victim standing on the forks, riding down with the load. At the top of this movement, the rafter piece and the machine suddenly shifted to the left. The machine fell over on its left side; the rafter crashed to the ground; and the victim jumped or fell to a grassy area on the ground. Emergency rescue was immediately called, and quickly transported the victim to a local hospital, but the man was dead on arrival due to severe internal bleeding. The operator of the forklift received minor injuries.
Recommendations based on our investigation are as follows:
During the summer of 2003, a 19-year-old man was killed while helping to dismantle a barn, using a telescoping boom forklift. The Iowa FACE program was notified of this incident a few days later and began an investigation. Sources of information included newspapers, the county Sheriff, the medical examiner, individuals from the company, the forklift manufacturer, the rental company which owned the machine, eyewitnesses, OSHA, and an insurance company. Photographs of the scene were received from the county Sheriff.
The employer was a small local greenhouse company. The owner had hired a work crew to dismantle and relocate an old barn. He rented a telescoping boom forklift and received operational instruction from the rental company, but it is unknown how much of this training was transferred to his son, who operated the forklift. Little information is available about this company, for the owner and his son were unwilling to talk about this incident.
The greenhouse company had purchased an old barn (peg barn), and was dismantling it for construction at a new location. The company owner hired five workers who were experienced in mortise and tenon / peg joinery construction. They had removed the roof and siding of the barn, and on the day of the incident, were disassembling the large rafter timbers supporting the roof (see Photo 3). Three of the men were climbing in the rafters. The victim was on the ground, and the fifth man was holding a rope to guide the rafter sections as they were lowered.
The greenhouse company owner rented a telescoping boom forklift from a local rental company, which provided basic training in operating the machine. No specific safety training was provided. The owner’s son operated the machine on site. It is unknown how much training he received in operating this machine and related safety issues. The machine was a JCB model 508C, manufactured in 2000. It had 8000 lb. (3600 kg) lift capacity, and a maximum lift height of 41.5 ft. (12.5 m). The forklift had a frame leveling system, which could compensate for about 12 degrees of incline to either side. The tires were fluid-filled. The machine had no stabilizers (outriggers).
The dimensions of the barn were approximately 90 x 48 ft. (27 x 14.5 m). The frame was built of fir timbers, mostly 6”x 8” (150*200 mm) or 8” x 10” (200*250 mm) in size. At the time of the incident, the forklift was located on the west side of the barn. The terrain around the barn was sloping to the north. The roof and sides of the barn had been removed earlier and were lying in piles of debris on each side of the barn. The five men hired to dismantle the barn were experienced in relocating old barns of this type, and had recently moved another barn using a similar boom forklift from the same local rental company.
The men had already lowered one section of the rafters that morning. The forklift was re-positioned for the next section near the barn driveway / ramp on the west side of the barn. The operator positioned the forklift in the middle of the rafter section. This put the right wheels of the forklift in the driveway / ramp area, with the left wheels lower in grass to the side (see Photo 4). The frame leveling control was used to compensate for the sloping ground, and it was in its maximum position. It was the crew’s normal procedure for one man to ride up on the forklift to secure the beams to the forks, then, ride back down with the load. There was no personnel platform attached to this forklift, but the victim rode up on the forks of the machine. The forks were raised above the center portion of the rafter section and the section was secured with nylon slings to the forks. While the forklift provided support, other workers used pry bars and other tools to carefully remove pegs and loosen the joints. Once loose, the forklift would raise the section until it was free from the barn and then lower it to the ground in front of the forklift.
When the rafter section was raised sufficiently to clear the barn, it began to sway slightly. This was not unusual, as it was difficult to determine the exact center of gravity for the rafter sections. The forklift boom was not fully extended at this point, but was elevated to approximately 30 ft. (9 m). Suddenly, as the operator began to lower the rafter section, the load and the forklift began to fall to the left (north). The co-workers yelled and warned the victim but he had no safe escape. The forklift fell to the ground and the rafter section crashed and broke up next to the pile of roof debris. The victim rode partway down with the load, then, jumped and fell into the grass north of the barn. Rescue workers were called, and arrived in a few minutes, but the man had received internal injuries and was declared dead when transferred to the local hospital.
The forklift was tested later by the rental company and was found to be in normal working condition. The machine was not damaged in the incident, therefore, it received minor repairs and was put back into service.
The company was cited by OSHA for failure to provide a guardrail system, safety net system, or personal fall arrest systems for its workers. They were also cited for not providing adequate training to the forklift operator regarding safe operation of the machine, the limitations of the machine, and the requirements for stability.
Cause of Death
The official cause of death was, “chest trauma, lacerated left ventricle due to fall.” An autopsy was performed, which confirmed these findings.
Recommendation #1: A telescoping boom forklift should not be used on an incline which exceeds the limits of the frame leveling system.
Discussion: The frame-leveling system for this forklift was set at maximum tilt to compensate for the sloping ground. However, it appears that the incline was greater than the capacity of the leveling system. When a load is carried low, the machine is fairly stable. However, the weight and height of the load will work together to change the overall center of gravity of the machine. If the center of gravity at any time shifts beyond the tires of the machine, the machine will overturn. Factors that appear active during this incident are the ground sloping at / over the capacity of the leveling system, the raised boom, forces from the weight and swinging of the load, lack of outriggers, and machine movements. Other factors which could contribute to overturning include: tire pressure, soil/surface conditions, wind speed and direction, swaying of the load, and movements (driving, turning, braking) of the machine. In addition, the ground slope was not uniform for front and rear wheels. The ramp incline created a greater slope angle for the front wheels compared to the rear wheels. This might have also compromised the machine’s stability or influenced the effectiveness of the frame-leveling system.