On the evening of the incident, the victim and his co-worker picked up their job assignments from their supervisor. One of their assignments was to replace a damaged tire from a multi-piece wheel assembly from a passenger boarding bridge. Workers on the previous shift had removed the multi-piece wheel assembly and placed it in the maintenance shop. The valve stem was in place, but there was no other indication or communication about whether the wheel assembly had been deflated at the time it was placed in the maintenance shop. At approximately 11:15 p.m., the victim and co-worker began the process of disassembling the tire and wheel. The victim was standing over the tire and wheel assembly using an electrical impact wrench and socket to remove the nuts on the 12-bolt pattern while the co-worker laid on the floor to access the nuts on the bottom side and hold them in place. As they were removing the eleventh bolt and nut, the air pressure inside the tire exceeded the holding capacity of the remaining nut and bolt and an explosion occurred. The top portion of the wheel assembly struck the victim in the neck, propelling him several feet in the air and causing him to land on the concrete floor. The co-worker was knocked unconscious and had severe injuries. The noise of the explosion alerted other workers within the surrounding area. Emergency services were immediately notified and responded, but the victim was pronounced dead at the scene. The co-worker was transported to a local hospital where he was treated for his injuries and released several days later.

According to the death certificate, the cause of death was blunt force trauma to the head and neck.

The CA/FACE investigator determined that, in order to prevent future incidents, employers with workers who change multi-piece tires should:

Recommendation #1: Implement policies and procedures as part of a safety program to ensure that tires are deflated prior to wheel disassembly.

Discussion: In this incident, the victim and co-worker began working on the wheel assembly without deflating the tire. The employer had written safety procedures and training that included the deflation of tires, and the victim had performed this task many times in the past. According to employer procedures, the workers on the previous shift were responsible for deflating the tire prior to removal from the boarding bridge. It is not known why the tire was not deflated at the time it was removed and placed in the maintenance shop. It is also not known if the victim assumed that the tire was deflated prior to beginning work. The warning label (Exhibits 5 & 6) regarding deflation was present on the tire, and the valve was still present.

The victim was an experienced employee and had disassembled the tire safely on numerous occasions in the past. The company policy was to have workers deflate the tire prior to removing it from the boarding bridge. In this procedure, the valve stem must be removed, and the tire is then taken to the maintenance shop for disassembly. In this incident, the tire stem was in place and the tire inflated. It is not known if the victim may have assumed that the tire had been deflated, but he did not verify by checking the valve stem. Although the employee had received safety training, there was no written method or active communication to ensure that the tire was deflated by workers on the prior shift. Although there was a requirement that the valve stem should be removed prior to placing in the maintenance shop, there was no effective procedure to ensure that compliance with this occurred. For example, written check-off sheets and/or periodic and regular safety audits with direct observation can be used to ensure that safe work practices are followed. In addition, employee safety training should be verified through written testing, oral confirmation, or demonstration. If these procedures had been implemented, the victim may have realized that the tire was still inflated and this incident could have been prevented.

Recommendation #2: Remove all pneumatic tires and replace with solid tires.

Discussion: In this incident, pneumatic tires were used for the boarding bridge, and they required periodic changing due to wear. Changing a pneumatic tire always presents a potential hazard of explosion with serious injury. Solid rubber tires are often filled with compressed polymers (plastic) rather than air or can be a solid molded product. When solid tires are changed, they cannot explode and pose a risk to personnel. If a solid tire had been used at this work site, it could not have exploded, thereby preventing this fatality.

Recommendation #3: Consider providing employees with certified training in commercial tire service (CTS), or hire companies with CTS technicians.

Discussion: Tire changing is a task that requires specialized skills and training in order to ensure that the task is performed safely. Tire pressure entails a serious risk of explosion, and working with tires also has a number of other risks. Tires have increased in size and mass and, consequently, the tire pressure has also increased. Workers should receive specialized certifications to ensure safety measures are understood and implemented. For example, the Tire Industry Association is an organization that certifies employees in commercial tire service (CTS) and can augment safety training provided by the employer. Alternatively, the company could have hired an outside contractor with certified CTS technicians. If the tire had been changed by a CTS technician, this death may have been prevented.

Additional Exhibits

Exhibit 5. Warning sticker placed on all tire/wheel assemblies used on passenger boarding bridges.

Exhibit 6. Second warning sticker placed on all tire/wheel assemblies used on passenger boarding bridges.