Hazard

Employees servicing tires were exposed to the hazard of being struck by material released during an exploding wheel separation.

Process

Employees were servicing a flat tire mounted on a multi-piece wheel on a forklift truck.

Activity at time of incident:

An employee was attempting to loosen a tire lock by tapping on it with a ratchet.

Incident Description

Setting:

A 20-ton forklift truck with dual front wheels and single rear wheels is parked in the maintenance shop. The left front inner tire on the forklift is flat, and three employees - the port manager, a crane operator, and a stevedore - are attempting to remove the outer tire to access the inner flat tire.

Incident:

At the time of the incident, the crane operator had removed all but two nuts from the wheel retaining clamps that held the tire lock. All three employees were standing next to the tire. While the outer tire was still pressurized, the crane operator began to tap on the tire lock with a ratchet to get the lock loose. The tire exploded and components of the wheel assembly struck the three employees and threw them approximately 15 feet from the forklift. The impact killed the crane operator and seriously injured the two other employees.

Relevant Factors:

None of the employees were trained in the proper procedures for servicing tires such as the one involved in the incident.

The wheel involved in the incident had numerous safety deficiencies. The tire was overinflated (the tire manufacturer recommended a maximum pressure of 50 psi and a pressure of 70 to 80 psi was maintained in the tires on the forklift), and the side wall of this overinflated tire was severely worn.

Additionally, the tire's split rim lock had been damaged during installation and was welded in place in order to seat the rim and tire. Moreover, the wheel flange was badly damaged.

The split rim tires were frequently repaired on site. However, there was no restraining device, such as a cage, rack, or other device capable of withstanding the maximum force that would be transferred to it during an explosive wheel separation. Additionally, the inflation hose was not equipped with a clip-on chuck nor was there sufficient hose to permit an employee to inflate the tire remotely, away from the danger zone.

Applicable Standards and Control Measures

• 29 CFR 1917.44(o)(3)(i): General rules applicable to vehicles - Servicing multi-piece and single piece rim wheels - Employee training. "Only employees trained in the proper procedures for servicing multi-piece rim wheels shall be assigned such duties."
• 29 CFR 1917.44(o)(5)(i): General rules applicable to vehicles - Charts and manuals. "The employer shall provide a chart containing as a minimum the instructions and information provided in the United States Department of Transportation, National Highway Traffic Safety Administration (NHTSA) publication 'Safety Precautions for Mounting and Demounting Tube-Type Truck/Bus Tires' and 'Multi-Piece Rim Wheel Matching Chart,' and pertinent to the type(s) of multi-piece rim wheels being serviced. The chart shall be available in the terminal's service area."
• 29 CFR 1917.44(o)(5)(ii):General rules applicable to vehicles - Charts and manuals. "A current rim manual containing the manufacturer's instructions for mounting, demounting, maintenance and safety precautions relating to the multi-piece rim wheels being serviced shall be available in the terminal's service area."

This hazard could have been prevented if the employer had ensured that the employee did not strike the tire rim or other wheel components while the tire was still inflated. Rather, the tire should have been deflated prior to its removal. Additionally, this hazard could have been prevented if the wheel assembly had been properly inspected and the rim's defective split lock had been replaced. During repair of the split rim tire, a restraining device should have been used. Also a clip-on chuck should have been used during inflation of the split rim wheels. Moreover, the employer should have ensured that only adequately trained employees, with demonstrated ability, be permitted to service the tires on the forklift. Specifically, the employer should have made available the applicable charts and manufacturer's instructions and should have ensured that employees follow the procedures set forth in these documents.

Other Relevant Standards and/or Control Measures

Tires should be inflated to the maximum allowable pressure indicated by the manufacturer. In this case, the tires should never have been inflated to more than 50 psi. Proper training in tire servicing, as described above, should address this very important aspect of tire safety.