Sep 14, 2012 — experience operating bulldozers and other heavy construction equipment. At 7:40 AM, the operator exited the bulldozer on its right side
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2 TABLE OF CONTENTS CONTENTS PAGE SUMMARY 3 RECOMMENDATIONS 3 INTRODUCTION 4 Employer 4 Employer Safety Program and Training 4 Victim 5 Equipment 5 INVESTIGATION 7 CAUSE OF DEATH 10 CONTRIBUTING FACTORS 11 RECOMMENDATIONS AND DISCUSSION 11 REFERENCES 15 INVESTIGATOR INFORMATION 16 FACE PROGRAM INFORMATION 16 ACKNOWLEDGMENTS 17
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3 SUMMARY In February of 2010, a 68-year-old male construction crew supervisor and heavy equipment operator died of injuries he received after being crushed between the track and fender of his bulldozer. The operator was employed by a contractor that does site development, single family home construction, and commercial construction work. He had previously owned a construction contracting business and had 48 years of experience operating bulldozers and other heavy construction equipment. On the day of the fatal incident, the operator was supervising a crew. The crew was working at a job site zoned for commercial development, where structural fill was being brought in and dumped and then leveled and compacted. As dump trucks haul ed fill onto the site, the operator was using a Caterpillar D4H Series II bulldozer to level the fill and was also directing the drivers as to where they should deposit their loads . At 7:40 AM, the operator exited the bulldozer on its right si de to speak wi th a truck driver about where the driver should deposit his load of fill. When he did this, he left the bulldozer running and did not set the parking brake. After giving instructions to the truck driver, track to return to the was standing on top of the track his elbow hit the transmission lever shifting the dozer out of neutral into reverse. When the bulldozer began moving backward , his left foot became caught between the moving track and the underside of the fender. As the bulldozer continued moving backward his left leg was pulled in and crushed. The operator was carried several yards before being ejected onto the ground. The truck driver with whom the operator had just spoken used his radio to call emergency medical services and then went to aid the operator . Emergency responders arrived within three minutes and the victim was taken to a hospital where he died of his injuries 15 days later. RECOMMENDATIONS To prevent similar occurrences in the future, the Washington State Fatality Assessment and Control Evaluation (FACE) investigation team recommends that bulldozer operators and employers who use bulldozers should follow these guidelines: Before leaving a bulldozer unattended, operators should follow manufacturer recommended operating procedures to ensure that the equipment is secured from movement. Employers should develop, implement, and enforce a written safety program that includes , but is not limited to, procedures for operators entering, exiting, and securing bulldozers against unintended movement.
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4 Employers should consider buying mobile construction equipment installed with an interlock safety system or operator presence sensing system which will prevent inadvertent movement of equipment. Additionally: Bulldozer manufacturers should consider design features of bulldozers so as to minimize or prevent injuries and fatalities of operators. INTRODUCTION In February of 2010, the Washington State FACE Program was notified by the Division of Occupational Safety and Health (DOSH) of the death of a 68-year-old male construction site supervisor and heavy equipment operator who died from injuries he received when his leg was caught between the moving track and fender of a bulldozer he was operating. In November of 2011, Washington State FACE investigators traveled to the employer office to interview the business manager and the development manager, who is also in charge of managing company safety. During the course of the investigation documents reviewed included the s death certificate, and DOSH investigation file. Employer The employer is a construction contractor that does single family home construction , commercial construction, and site development. The business was started in 2001 and its office is located in the incident city in Washington State. At the time of the incident the employer had 15 employees working either full-time or part-time, with some working in the office and others in the field. There were four employees at the incident site who were working full-time for the length of the project. The number of employees and the hours they worked varied depending on the number and nature of the projects. The crew had been working at the incident site operating heavy equipment to level and compact fill for a week and a half prior to the incident. Employer Safety Program and Training The employer had a written health and safety program; however, there was no specific language about safe equipment operation. The employer train ed employees in the safe operation of a particular piece of heavy equipment that they had not used before. The employer hired experienced equipment operators who had to demonstrate to the employer their knowledge of how to safely operate heavy equipment. All of their equipment operators were long term employees and were considered safe and
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5 competent operators. Occasionally the employer would hire an outside safety consultant to ensure that their employees were operating safely. The employer has a safety officer who, depending on the number of jobs the employer has , oversees employee safety for 3 to 4 hours or more per week. Safety meetings are held once a week by the safety officer . Typical topics at these meetings include discussions of specific safety relating to their planned activities, potential safety hazards , and the planned work and what everyone will be doing. On the day of the incident there was no safety meeting, as they had held one two days previously. The safet y officer was not present at the time of the incident. Victim The victim (hereafter referred to as the operator ) was a 68 – year – old male construction site supervisor and heavy equipment operator. He had operated a bulldozer and other heavy construction equipment for the past 48 years. P reviously , he had owned his own construction contracting business. For the past ten years, he had been working with this employer both full – and part – time. A self – taught heavy equipment operator , he cou ld run every piece of equipment the employer owned. H is employer and coworkers knew him to be an experienced and capable equipment operator who always stressed the importance of working safely. As a job site supervisor he directed the work being done at t he job site. He often combined operating a piece of heavy construction equipment with supervision of employees and other trades workers entering the job site to perform work, such as truck drivers delivering fill to the job site . Equipment The equipmen t involved in the incident is a 1991 Caterpillar D4H Series II track – type tractor, also known as a bulldozer . The employer purchased the bulldozer used about eight years previous and made no modifications to it. The bulldozer is powered by 4 – cylinder turbocharged diesel engine rated at 95 hp at 2,200 rpm (see photo #1) .
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6 Photo 1: Caterpillar D4H bulldozer at inc ident site. The transmission is engaged by a planetary power shift with three gears forward and three gears in reverse (see photo #2 ) . It is a type of The high track type of bulldozer has a high sprocket configuration for the track and the cab is higher from the ground than other bulldozers of comparable size. Photo 2 : Cab and operator transmission in neutral, thereby preventing movement of the equipment. Parking brak or set Transmission shifter lever Left steering clutch and brake Right steering clutch and brake
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8 allows the operator to safely exit the cab on the left side (see photo # 2 ) . If the brake is up easily exi ting (without having to step over the lever) from the left side of the cab (see photo # 3 ) . Photo 3 in neutral and According to the employer, t he safe method of entering and exiting the cab in this bulldozer is by the left side , as it reminds the operator to engage the parking brake in the position . This model bulldozer has steps and handholds on both sides of the equipment, allowing cab ingress and egress from either side. The operator exited the right side of the cab and walked a few feet over to the window of the truck to speak with the driver . After giving instructions to the driver as to where to dump the fill, the operator walked to the left side of the bulldozer and walked up its left tr ack , starting at the front of the tr ack . There are several handholds positioned on the As he was standing on the top of the tr ack and abo ut to enter the cab, he reached with his left hand toward the support handhold near the transmission shifter lever and his elbow hit the transmission shifter lever , knocking it out of neutral into reverse , causing the bulldozer to start moving backward . When the track started to move his left foot became caught between the track and the underside of the fender (behind which is the battery box). His Transmission shifter lever in neutral Parking brak or not set
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9 left leg was pulled in and crushed between the track and the underside of the fender and he was thrown on his back, landing on the track (see photos #4 and #5). He was carried away by the dozer and was ejected from the equipment and landed on the ground about 5 to 6 feet in front of the truck. Photo 4: Left side of bulldozer showing track, access system handholds, and pinch point between track Photo 5 neutral position, thus preventing unintended movement of the bulldozer. In this incident, the parking brake victim attempted to re-enter the cab he inadvertently knocked the transmission shifter lever into reverse, causing the bulldozer to move. Parking brake Transmission shifter lever Pinch point leg was caught. Hand holds
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10 The truck driver with whom the operator had just spoken made a call from his truck radio to a second driver who was on site to call emergency medical services (EMS) and then he went to aid the operator . Another truck driver went to stop the bulldozer that had continued to travel in reverse (see photo #6). The employer safety officer, who also works as an emergency medical technician at the local fire department and was on duty, heard the call over his radio and arrived at the scene within three minutes, just ahead of the fire department EMS responders. The operator was taken by ambulance to a hospital where he died of his injuries 15 days later. Photo 6: Incident scene showing where the bulldozer came to rest after an employee turned it off. CAUSE OF DEATH The medical examiner listed the cause of death as multiple lacerations and long bone fractures, traumatic amputation of the left leg, and pelvic fracture with secondary bacterial sepsis due to or as a consequence of blunt force injury of the extremities and pelvis.
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11 CONTRIBUTING FACTORS Occupational injuries and fatalities are often the result of one or more contributing factors or key events in a larger sequence of events that ultimately result in the injury or fatality. Washington FACE investigators identified the following factors that may have contributed to the worker being crushed between the moving tread of a bulldozer and : Failure to set the parking brake before exiting the cab. Failure to shut down the machinery. RECOMMENDATIONS AND DISCUSSION Recommendation #1: Before leaving a bulldozer unattended, operators should follow manufacturer recommended procedures to ensure that the equipment is secured from movement. Discussion: After the incident, the operator was conscious and told the . Setting the parking brake locks the equipment in neutral which prevents it from moving. The employer safety manager reported that the victim liked to work quickly and believes that his haste played a role in his not following the proper procedures when leaving the equipment unattended. Though the operator had 48 years experience operating a bulldozer and was very aware of the procedures used to safely operate a bulldozer, in this instance he did not follow those procedures. followed is critical in order to prevent unwanted movement of the equipment while the operator is outside the cab or entering and exiting the cab. steps when parking the machine: 1 1. Park on a level surface. If it is necessary to park on a grade, block the tracks securely. 2. Apply the service brake to stop the machine. 3. Move the transmission control lever to neutral and the speed control to low idle. 4. Engage the parking brake control. 5. Lower all attachments to the ground. 6. Stop the engine. 7. Turn the engine start switch key to off and remove. 8. Turn the battery disconnect switch key to off and remove.
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