SUMMARY : CASE 192-036-01
A tree trimmer was pruning walnut trees in an orchard. He used a lift bucket (a "cherry picker") attached to a mobile platform, which he could raise, lower and move along the rows of trees while standing in the bucket. At the edge of the orchard, high voltage power lines crossed over the last row of trees just above the tree tops. The power company was usually called in to trim these trees.
However, on this day the worker began pruning the last row of trees. He raised his lift bucket to the top of one tree. His pruning shears touched the power line and he was electrocuted. Although co-workers pulled the lift bucket and platform away from the power lines with a truck, the worker died instantly. His body was badly burned.
How could this death have been prevented?
On April 1, 1992, at 3:15 p.m., the California Occupational Safety and Health Administration (Cal/OSHA) district compliance office was notified by an orchard owner of an electrocution in a walnut orchard. This fatal injury occurred at approximately 2:20 p.m. earlier that day, when a 38 year-old male Hispanic tree trimmer was electrocuted while pruning walnut trees.
Cal/OSHA notified NURSE Project staff of the incident on April 9, 1992. A Senior Safety Engineer from the NURSE project conducted an on-site investigation on June 2, 1992, and July 1, 1992 and discussed the incident with the farm owner and crew foreman. NURSE staff reviewed the medical examiner/coroner records and the Cal/OSHA investigation report.
This electrocution occurred on a family-owned farm of 1,000 acres, of which about half are planted in tree fruit and nuts and half in cotton. Approximately 300 casual (1 to 12 weeks per year) farm workers are employed by the farm during peak harvest season, and 15 workers are employed year-around. Cal/OSHA investigated the incident on April 6, 1992, and found the employer's safety program to be in compliance with Title 8 California Code of Regulations 3203 -- Injury and Illness Prevention Program. (As of July 1, 1991 the State of California requires all employers to have a written seven point injury prevention program: designated safety person responsible for implementing the program; mode for ensuring employee compliance; hazard communication; hazard evaluation through periodic inspections; injury investigation procedures; intervention process for correcting hazards; and a health and safety program.)
The tree trimmer had worked on this farm for several years as the foreman of a 30-worker crew, but then had returned to his home in Mexico. He returned to California and was hired in December, 1991 to prune trees in the orchards during the next spring season. He received two days of safety training at that time. Current farm safety policy includes tailgate safety meetings held every ten days. (Tailgate safety meetings are brief talks on safety practices by the foreman or supervisor at the work site before the day's work begins.) The employer noted that the tree trimmer had been warned of the presence of the power lines during the initial safety training in December, 1991. During the pruning season last spring, the power company had trimmed the trees near the power lines.
On April 1, 1992, at approximately 2:20 p.m., a tree trimmer was pruning walnut trees using a mobile lift bucket. The lift bucket is mounted on a platform that has a tricycle-type configuration, with dual wheels on each of the three axle points. One set of wheels, in the rear, steers the platform. The wheels in the front are used to move the unit. A diesel engine in the base of the platform powers the drive wheels and the hydraulic system. The control system for the hydraulic lift and the power system for the mobile platform are in the lift bucket, enabling the driver to stand in the bucket and operate the controls that raise and lower the bucket, and move the platform. Using mobile lift buckets for pruning eliminates the use of ladders and is more efficient. This lift bucket was not insulated because it was not intended for use around high voltage power lines. Therefore, the lift bucket was incapable of preventing electrical current from flowing through it to the ground.
At the time of this incident, the fatally injured tree trimmer and one other tree trimmer were working from two mobile buckets in the orchard. A 12,000 volt power line (30 feet and 3 inches above the ground) runs parallel and crosses the last row of trees (see diagram). At the time of the investigation, tree branches were observed to be touching the power line.
The tree trimmer was pruning the last row of trees adjacent to the roadway with the power lines over his head. The worker trimmed one side of the tree, then moved the platform into the roadway on the far side of the tree to prune the other side. He raised the bucket approximately 25 feet high (as high as the bucket could go) and lifted his pruning shears over his head. His shears then came into contact with the high voltage power line. Upon contact with the power line, a path-to- ground circuit was established and electricity flowed through the pruning shears, his body, and down to the ground through the platform.
Other employees on the farm used a truck to pull the mobile platform away from the power lines and lower the lift bucket. Farm employees also called 911, with the fire and ambulance service, the county sheriff and the coroner's office all responding. The coroner noted the tree trimmer was lying on the ground under the tree where he had been working, and pronounced him dead at 2:40 p.m.
The deceased tree trimmer had deep and extensive abdominal burns. These burns corresponded to clothing burns and burns on the plastic bumper of the inside edge of the lift bucket where he had been leaning. There were also burns on his thumbs and fingers, the front left side of his chest, his right thigh, right shin, and toes. The metal shaft and plastic handle of the pruning shears were blackened where he had been holding them. The boom (neck leading from the platform to the bucket) of the lift bucket showed electrical discharge markings such as blackened and peeling paint, and two of the six wheels had electrical burns down the side with the ground next to them burned.
The coroner reported the cause of death as cardiac arrest and arrhythmia due to electrocution with extensive thermoelectric burns.PREVENTION STRATEGIES
For further information concerning this incident or other agriculture-related injuries, please contact:NURSE Project
2151 Berkeley Way, Annex 11
Berkeley, California 94704
1111 Fulton Mall, Suite 212
Fresno, California 93721
1000 South Main St., Suite 306
Salinas, California 93901
This document was extracted from a series of the Nurses Using Rural Sentinal Events (NURSE) project, conducted by the California Occupational Health Program of the California Department of Health Services, in conjunction with the National Institute for Occupational Safety and Health. Publication date: August 1992.
The NURSE (Nurses Using Rural Sentinel Events) project is conducted by the California Occupational Health Program of the California Department of Health Services, in conjunction with the National Institute for Occupational Safety and Health. The program's goal is to prevent occupational injuries associated with agriculture. Injuries are reported by hospitals, emergency medical services, clinics, medical examiners, and coroners. Selected cases are followed up by conducting interviews of injured workers, co-workers, employers, and others involved in the incident. An on-site safety investigation is also conducted. These investigations provide detailed information on the worker, the work environment, and the potential risk factors resulting in the injury. Each investigation concludes with specific recommendations designed to prevent injuries, for the use of employers, workers, and others concerned about health and safety in agriculture.
Disclaimer and Reproduction Information: Information in NASD does not represent NIOSH policy. Information included in NASD appears by permission of the author and/or copyright holder. More