During the fall of 2000, a 46-year-old worker at a tire assembly plant was caught and crushed in a tire assembly machine. The machine was making prototype agricultural tires, which differ significantly in assembly procedure from other tires manufactured at this facility. The large computer-controlled machine normally operates in automatic mode while workers build tires on a routine basis during their work shift. On the day of the incident, the machine malfunctioned while working on a prototype tire, and a maintenance crew was called in. The operator cut out the partial tire and removed it from the machine. When they finished the repair, the machine was reset to zero, in manual mode, to a ‘start’ position, in order to build another tire. However, the machine’s computer control system jumped to an "operational mode" and caught the victim off guard from his backside, crushing him in the left pelvic region. Co-workers immediately assisted the man, and he remained alert and conscious during transport to the hospital and during his evaluation prior to surgery. Following surgery he was placed in intensive care where he deteriorated and died 33 days later from multiple system failures and sepsis. Initial investigation of the tire assembly machine determined that computerized command and control information from the previous tire production run was still stored in the machine's computer system, even though it had been manually reset to zero. Consequently, the tire machines unanticipated operation resulted from this "residual" computerized command and control information. The tire company immediately shut down the machine and later addressed the software problem. Company officials also shut down a similar machine being used at a different tire plant in another state. Multiple safeguards were incorporated into the operation of the machines to eliminate the possibility of recurrence. Recommendations based on our investigation are as follows: 1. Employers should ensure that machines are safeguarded to protect all employees in the machine area. Computerized machining processes should allow the machine to operate in fail-to-safe mode during and following repairs or general maintenance. Lockout/tagout requirements specified in 29 CFR 1919.147 shall be followed (if employees are not protected by machine guarding). 2. Job Hazard Analysis should be performed and Safe Operating Procedures should be developed with subsequent training of employees to follow on machines and equipment (including modifications and/or new processes) to which employees are exposed.
Region-7; Accident-analysis; Accident-prevention; Accidents; Injuries; Injury-prevention; Traumatic-injuries; Work-operations; Work-analysis; Work-areas; Work-performance; Work-practices; Safety-education; Safety-equipment; Safety-measures; Safety-monitoring; Protective-measures; Training; Machine-operation; Equipment-design; Equipment-operators; Equipment-reliability; Computer-aided-manufacturing; Computer-software