OSHA Hazard Information Bulletins1
Unauthorized Modification of a Forklift Carriage Assembly

June 20, 1996




  • Acting Director
  • Directorate of Technical Support


  • Hazard Information Bulletin1: Unauthorized Modification of a Forklift Carriage Assembly

The Chicago Regional Office brought to our attention an accident that resulted in a fatality. At the time of the accident, the employer had engaged in the unsafe practice of modifying a forklift truck attachment.

Workers in a company that fabricates material handling equipment for the road paving industry were welding a 216 3/4-inch long 3" by 3" angle iron that was bent into a semicircular shape onto the top side of a cylindrical silo. This step occurs at the end of the silo fabrication process. When completed, the silo is about 11 1/2 feet in diameter, 50 feet long, and weights 10,000 lbs. To perform this task, the silo was placed on its side on a set of power-driven rollers with a crane. To weld the semicircular angle iron onto the silo, the welding end of the silo had to be lifted up. To lift the silo, an eight-foot long boom was attached to the fork carriage of a forklift. The forklift operator inserted the extended boom 3' into the silo, tilted the mast 15 degrees backward, and raised the fork carriage. A worker then went underneath the fork carriage to measure the diameter of the silo. He was crushed to death when the 500 lb. fork carriage and 250 lb. extension boom disengaged from the top truck carriage bar and fell on him.

Attaching an eight-foot boom to the fork carriage to do the above task is a modification of the forklift. This modification affects the capacity and the safe operation of the forklift and must have the forklift manufacturer's prior written approval [29 CFR 1910.178 (a)(4)]. Also, 29 CFR 1910.178 (m)(2) prohibits a worker from attempting to measure the diameter of the silo from under the fork carriage. It states, "No person shall be allowed to stand or pass under the elevated portion of any truck, whether loaded or empty".

The fork carriage was mounted on the top truck carriage bar with two top hooks engaged and two bottom hooks bolted onto the lower pads of the fork carriage. The fork carriage is an Industrial Truck Association Class II attachment with capacity ratings between two thousand and fifty-five hundred lbs. When the load of the silo was placed at the tip of the extended eight-foot boom, it may have exceeded the capacity of the attachment, causing the attachment to jump off the top truck carriage bar.

Compliance and consultation personnel should remind users of forklifts that any modifications that affect the capacity and safe operation of a forklift must have written approval from the manufacturer.

Please distribute this bulletin to Area Offices, State Plan States, Consultation Projects and appropriate local labor and industry associations.

1 The Directorate of Technical Support issues Hazard Information Bulletins (HIBs) in accordance with OSHA Instruction CPL 2.65 to provide relevant information regarding unrecognized or misunderstood health hazards, inadequacies of materials, devices, techniques, and safety engineering controls. HIBs are initiated based on information provided by the field staff, studies, and concerns expressed by safety and health professionals, employers and the public. Information is compiled based on a through evaluation of available facts, and in coordination with the appropriate parties.