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 Selected Occupational Fatalities Related to Vehicle-Mounted Elevating and Rotating Work Platforms as Found in Reports of OSHA Fatality/Catastrophe InvestigationsU.S. Department of Labor Occupational Safety and Health Administration 1991 Material contained in this publication is in the public domain and may be reproduced, fully or partially, without permission of the Federal Government. Source credit is requested but not required. Permission is required only to reproduce any copyrighted material contained herein.  Selected Occupational Fatalities Related to Vehicle-Mounted Elevating and Rotating Work Platforms as Found in Reports of OSHA Fatality/Catastrophe InvestigationsU.S. Department of Labor Lynn Martin, Secretary Occupational Safety and Health Administration Gerald F. Scannell, Assistant Secretary Office of Statistics Stephen A. Newell, Acting Director July 1991 ABSTRACT This study of occupational fatalities related to vehicle-mounted elevating and rotating work platforms that occurred during the period 1986-1990 continues the utilization of the OSHA fatality/catastrophe investigation reports as a source of information on how fatal workplace incidents occur. Thirty-four selected case files are utilized involving 35 fatalities. The purpose of the analysis is to provide information that would highlight areas of interest for standards review and development, to aid in regulatory assessment, in training and educational programs, in consultation programs and in targeting compliance efforts. Accident information which is available within OSHA is used. Each incident was assigned to one of four categories of factors most likely responsible for precipitating the incident even though several factors may have been present. These categories are: Operating Procedures, Equipment/Material/Facility Related, Environmental Conditions or Other. Employee activity at the time of the incidents is examined. Standards cited directly related to the incident are summarized. All thirty-four cases are included as case studies in this report. Death from falls fromelevation and contact with sources of electrical current (electrocutions) accounted for 80% of the fatalities. I. INTRODUCTION II. MATERIALS AND METHODS A. Materials B. Methods III. ANALYSIS A. Types of Fatal Incidents B. Employee Activity at the Time of Injury C. Standards Cited IV. CONCLUSION A. Problem Areas B. Secondary Factors C. Preventive Measures D. Data Source REFERENCES APPENDICES A. Classification of Variables Tables I. Types of Fatal Incidents Identified in Case Files II. Types of Accidents III. Employee Activity at Time of Injury IV. Work Location at Time of Injury V. Numbers of Fatalities by Occupations B. Standards Cited C. Definitions I. Definitions of Vehicle-Mounted Elevating and Rotating Work Platform Terms II. Types of Incidents III. Factors Related to Fatal Incidents D. Forms I. OSHA 36 II. OSHA 170 III. Codes E. Available Studies in the Occupational Fatality Series Selected Occupational Fatalities Related to Vehicle-Mounted Elevating and Rotating Work Platforms as Found in Reports of OSHA Fatality/Catastrophe Investigations
I. INTRODUCTION In response to the need for descriptive data on how fatal workplace incidents occur, the Division of Data Analysis has conducted this study of selected occupational fatalities related to vehicle-mounted elevating and rotating work platforms. This information is useful for standards review and development, as an aid in regulatory assessment, in developing training and educational programs, in providing consultation and in targeting compliance efforts. It follows previous studies of occupational fatalities that utilize case reports of OSHA fatality/catastrophe investigations by the compliance offices. OSHA regulations require that all workplace fatalities be reported to the nearest Area Office in State and Federal jurisdictions within 48 hours of the event. A completed preliminary Fatality/Catastrophe Event Report Form (OSHA 36) is reviewed by the Area Director to determine if an investigation is warranted. If an investigation is performed, the compliance officer files a report of the incident in the Area Office containing a description of the incident, statements of witnesses, a list of citations to be issued for violations of standards, and other related information. Copies of case files are obtained from Area Offices under Federal jurisdiction and are the basis for this report and those preceding it. The information in the case files are used for descriptive information on how fatal accidents may occur. In addition, an analysis of citations for violation of existing standards is made. Short narratives of the incidents are presented. II. MATERIALS AND METHODS A. Materials Thirty-four cases involving thirty-five fatalities are examined in this study. These which occurred during the period (1986-1990), were identified and obtained from the Area Offices. The 34 cases represent only those cases we could identify in the federally covered states. These cases do not represent all such incidents in the Nation for the time period. Not included are cases involving scissor lifts, platforms suspended from cranes, front end loaders, platforms on forklifts, man cages, etc. The included cases covered general industry and construction work areas. The case files include, in varying amounts of detail, description of the incident, statements of witnesses, other supporting documents, and a listing of issued citations of standards violated. In some cases, the accident information may be partially conjectural as the event may not have been observed at the moment of occurrence. Also, there is no standard accident investigation procedure used for all accidents, hence all points important for reconstructing the event may not have been included. B. Methods Summaries of accident codes show little to indicate what led to and caused fatal incidents. See Appendix D, page D-3. Details provided by an indepth accident investigation are required. Information from the case files are examined and a sequence of events determined. The clustering of similar occurrences are noted and classification schemes devised keeping in mind future standards modification and development. Citations issued that are relevant to the incident are examined. Finally, all thirty-four of the cases are presented to provide insight into how they occurred. After reviewing all cases, four classification systems for the data were used. These were based on (1) the type of incident, (2) the type of accident (3) employee activity at the time of the fatal injury, and (4) location at the time of accident. These classifications are discussed in the following sections.
After the cases were coded by type of incident, type of accident employee activity and work location, relevant data summaries were made. All cases (34) are presented by incident type classification in the report. III. ANALYSIS The analysis consisted of seven parts.
Aerial Device: Any vehicle-mounted device, telescoping or articulating or both which is used to position personnel. Aerial Ladder: An aerial device consisting of a single or multiple section extensible ladder. Articulating Boom Platform: An aerial device with two or more hinged boom sections. Extensible Boom Platform: An aerial device (except ladders) with a telescope or extensible boom. Telescopic derricks with personnel platform attachments shall be considered to be extensible boom platforms when used with a personnel platform. * Code of Federal Regulations 29 1910.67 and 1926.556, OSHA, U.S. Department of Labor, July 1, 1989. Insulated Aerial Device: An aerial device designed for work on energized lines and apparatus. Mobile Unit: A combination of an aerial device, its vehicle and related equipment. Vertical Tower: An aerial device designed to elevate a platform in a substantially vertical axis. Platform: Any personnel carrying device (basket or bucket) which is a component of an aerial device. Vehicle: Any carrier that is not manually propelled. Thirty-four incidents involving thirty-five fatalities are examined. For each incident type, a summary of findings is followed by case studies* of all 34 incidents in the appropriate categories. These are as follows: A. Types of Fatal Incidents Operating Procedures These incidents occurred when: There was a failure to take proper safety procedures around energized overhead power lines. (see cases 1 through 5) Employee elevated or otherwise moved aerial platform (basket/bucket) into energized power lines. (see cases 6 through 8) There was careless operation of the truck/vehicle of the aerial device. (see case 9 and 10) Outriggers (stabilizers) were not extended or were extended improperly. (see cases 11 and 12) There was a failure to operate boom safely; boom off center. (see cases 13 and 14) Workers untrained/unfamiliar with aerial lift were allowed to operate it. (see cases 15 and 16) Workers cut into energized lines/wires. (see case 17) * The Word "deceased" is used in some narratives at points prior to the exact time of the fatal incident for better identification and clarity. Under the heading, Injury, the following codes are used: F, fatality; H, hospitalized injury; and, N, non-hospitalized injury. Front wheels of aerial lift vehicle slipped off trailer when unloading it. (see case 18) Worker overreacted to controls while operating bucket. (see case 19) There was a failure to follow instructions. (see case 20) Lack of visual/oral communication occurred. (see case 21) Worker placed himself in dangerous work position without fall protection. (see case 22)
DESCRIPTION OF INCIDENT: The service technician was "changing out" a pole, i.e., securing a cable TV line from an old pole to a new pole nearby. He was working from the bucket of an uninsulated aerial lift. He had attached a "come along" to the cable to hold it in place while he transferred it from the old pole to the new pole. The electrical conductor on the old pole was about 3 1/2" from the new pole. The new pole contacted the 20 KV (phase to ground) power line. The employee was apparently in contact with the new pole and the cable TV line. He received an electrical shock and fell out of the bucket approximately 23' to the ground. He suffered no broken bones. The cause of death was electrocution. He was not wearing a safety belt and was not tied off. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: A severe localized thunderstorm had occurred and lines were down. Crews were out repairing lines. A lineman, using rubber gloved hands was removing grounds while in an elevated bucket. The grounds were put into primaries from the secondary neutral, and upon removing ends from the primaries, the employees put one of the two ends in the bucket. While he was repositioning to remove the other ends from the neutral, his upper part of body (ear) came in contact with a primary line (5KV). His right thigh was touching the free end of the grounds which were still attached to the secondary neutral. The lineman slumped in the bucket following a flash. The aerial bucket was lowered and CPR was given. He was dead on arrival at the hospital. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The employee was grounding overhead guys with a piece of No. 6 unprotective energized lines copper wire when he came in contact with the bracket holding the hot phase wire (7,200 volts). The employee was not wearing protective gloves and/or sleeves. He was elevated approximately 29 feet in the bucket of an aerial lift. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: Two employees were completing a job of installing a new customer service line to a street light pole. One employee was in the bucket of an aerial lift; the other was on the light pole. Both had taken off their rubber gloves while preparing to descend. The senior lineman on the pole was removing his safety belt from around the pole to descend to a point below the light fixture when he came in contact with low voltage (120v to 8kv) live lines. He called out "get me out of these lines". The grounding wire from the street light fixture had been cut in two and not replace. Before the lineman in the bucket could turn around to him, he fell to the ground approximately 31 feet below. He died in a hospital fours hours later during an operation. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: A lineman, working from an aerial bucket, was electrocuted while in the process of reconnecting a line. He was placing armor rod on the wire before the wire was installed on the insulator. The armor rod material he was carrying in the bucket with him came in contact with a 7,200 volts energized power line. He had no barriers or guards in place to protect against making contact with live line phases and he was not wearing protective rubber gloves. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The deceased, a lineman, was cleaning insulator bushing and strain arresters while in the insulated bucket of a mobile aerial lift. He was using ground corn cob abrasive under compressed air flowing through a 3/4 inch by 13 foot fiber glass wand. The deceased signaled the ground man that he was through. The ground man proceeded to turn off the air on the cob machine and looking up, saw that the bucket was in contact with the middle uninsulated 34,500 V transmission line. The lineman then moved the bucket and brought the middle wire in contact with the uninsulated outside wire going phase to phase creating a loud crackling sound, fire and smoke. The lineman attempted to move the wire off his back and then slumped forward falling out of the bucket. He fell 53 feet striking head against a front fender of the truck before hitting the ground. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The lineman, who had ten years of experience in the field, was working from an aerial lift stringing support wires for a TV cable. Tree branches were in the way and he used a saw to cut them. During the trimming operation, he elevated the bucket and his head contacted a 7,620 volt primary line. The driver below saw a flash and the lineman fell back into the metal bucket. He was wearing a "baseball" cap and not a hard hat. He was not wearing a safety belt and lanyard. He was lowered by the driver and policeman assigned to the area attempted CPR but the lineman had expired. The metal bucket became grounded through the attached stringing wire which in turn contacted a guy wire. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The employee moved his mobile aerial tower in position over three phases of a 7,200 volt line. He lowered the bucket between the outer and middle lines. The non-insulated portion of the boom tip which had rivets/bolts sticking out contacted the middle phase. Fault current then traveled through the boom tip to the partially detached metal clad hydraulic tool circuit on the outside of the bucket which had been wired to the safety belt ring located on the inside of the insulated bucket. It finally traveled to the safety belt tie off ring. A copper wire was tied to this ring holding a pair of large lineman's pliers. The employee's knee contracted the energized set of pliers at the same time he was holding a de-energized/partially grounded wire. This completed the circuit which electrocuted the employee. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The driver parked the lift truck in the uphill direction of the inclined street and perpendicular to the transformers on the power pole. He set the emergency brake but did not chock the wheels nor engage the outriggers. As the serviceman (deceased) inspected the transformers from the aerial bucket, the truck began to drift backwards downhill. The driver applied the brakes. However, the lift bucket contacted the transformer crossbar and, by shear weight of the vehicle, twisted the pole approximately 20 degrees compressing the exterior portion of the bucket with enough pressure to shatter it. Debris were scattered approximately 20 feet. The interior bucket section along with the serviceman fell 35 feet to the ground. The remaining boom section caught the transformer guy wire while a bystander attempted to crib the wheels with a steve which brought the truck to a halt. The employee died from multiple injuries. He was not wearing a body belt attached with a lanyard to the bucket or basket. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: A lineman was pulled from the bucket of an aerial lift truck he was riding in by a low hanging insulated communication cable. The cable was suspended approximately thirteen and one-half feet above the center of the west-bound lane of the road. The truck was relocating from one work location to a another location 1.9 miles away. He was replacing insulators at different locations along the line. The lineman was not secured inside the bucket by a safety belt and lanyard. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: Employees were engaged in tree trimming operations using a hydraulic operated bucket truck. After arriving at the site one of the employees set up the truck by placing the outriggers. He than mounted the bucket and connected the lanyard to his safety belt. He began to unfold the boom rotating 45° from parallel. When the upper boom was approximately 20° from level, the truck overturned causing the boom and bucket to fall 50' striking the ground. The employee in the bucket was ejected head first onto the street payment resulting in fatal injuries. It was determined that immediately after the truck turned over the left outrigger was in the stowed position. Two possibilities were considered: (1) the outrigger was never extended or was partially extended but not to the extent of leveling the truck, and (2) an employee mistakenly retracted the outrigger. STANDARDS CITED RELATED TO THE INCIDENT: No citations were issued.
DESCRIPTION OF INCIDENT: Two employees were using an aerial lift or Cherry Picker while replacing overhead lights at a car rental maintenance yard. The truck overturned with the two men in the bucket. The bucket had been moved up to the light after employees placed a light at another pole location. The outriggers had not been extended and the bucket fell with the overturning truck. It was determined that the outriggers had been extended at the previous location. One man was killed, the other received a broken leg in several places. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The worker, owner of his electric company, was working from an elevated bucket on an vehicle mounted aerial lift. He was preparing to change out some light bulbs on parking lot light poles which were 80' in height. He wanted to check to see what type of bulbs would be needed. He extended the outriggers on back of the truck and began to ascend in the bucket. The boom was off-center and the truck tipped to the right side. The elbow of the extended boom hit a car on the parking lot and this propelled him from the bucket which was approximately 25' from the ground level. He fell between two cars striking his head. Death was due to cardio-pulmonary arrest and multiple injuries including a fractured skull. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: A construction crew was using an aerial lift truck to trim trees from the right-of-way of a 7,620 volt power line. An employee was leaning against the side of the truck. Another employee was in the bucket over a high voltage line trimming trees. When repositioning, the boom touched the high voltage line, energizing the truck. The employee on the ground was electrocuted. The employee in the bucket stated that he was unable to move the boom to come down. When the employee on the ground fell, the employee in the bucket could then operate the boom. He came down and pulled the employee from under the truck, checked his airway and tried to pump air into his lungs but was unable to get any response from him. He then drove to the office and reported the accident. An ambulance was dispatched to the scene. STANDARDS CITED RELATED TO THE INCIDENT: No citations were issued.
DESCRIPTION OF INCIDENT: The employee was operating an aerial lift platform which he had borrowed. He was untrained and unfamiliar with its operation. He was changing light bulbs on the hanger roof 55 feet from the ground. The equipment tipped over resulting in his death when he moved the bucket counter-clockwise to make another approach to a light. At this time, the bucket went behind the center of rotation with the weight of the entire boom on one side. The aerial device can tip over if the bucket goes beyond the center line of rotation. The aerial platform was a self-contained hydraulically operated unit mounted on a truck chassis. Retractable outrigger stabilizers were located on both sides of the mainframe. The extended outrigger sections measured 3' 6" long, 5" thick and 7" wide. These were extended at the time of the accident. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: Two untrained elevated highway construction employees were ascending from ground level to an elevated construction level in the bucket of an articulating aerial boom lift during a night shift. An eighteen wheel truck struck the platform as it swing over the unlighted and poorly marked interstate highway throwing the unbelted employees onto the highway. A second vehicle ran over one employee resulted in death. The second employee was severely injured by the fall and hospitalized. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The employee was in the process of replacing a neon unit on an electric sign (the sign was de-energized). He was working from an aerial device 40' above the concrete ground below. When he energized the sign, the neon unit did not light up. He used a high tension cable to bypass the neon unit while trouble shooting the sign. The employee apparently tried to cut or push the cable with a pair of pliers while the sign and cable were still energized (15,000 volts). He became part of the electric circuit and fell 40' to the ground. He was not wearing a safety belt. The autopsy revealed death by electrocution. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The employee, while in the platform bucket, was unloading a powered mobile work platform from a trailer. The rear wheels contacted the ground as the front wheels slipped off the trailer. The impact caused the telescoping boom to spring throwing the employee into the air. The employee landed on the guard rail of the bucket. His weight pushed the bucket down causing the bucket to contact the trailer bed. The boom sprang again causing the employee to again be thrown from the bucket into the air. He again fell onto the bucket guard rail and tumbled on to the pavement approximately 8' below. He was taken to the hospital where he died from head and chest injuries. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: Two men working on structural steel were in the bucket of an aerial lift. They relocated and then extended the boom instead of elevating it. One of the employees head, neck and chest was pinned against a steel rafter by the control pulpit of the aerial lift platform (bucket) he was operating. It was the result of excessive forward motion of the "car body" of the lift caused by over-activation of the control for the situation at hand. The other employee was unhurt. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: A lead lineman and one ground lineman were sent to install a new anchor guy wire on a power distribution line after removing the old. The employees were instructed to dump or de-energize the hot line before beginning work. They did not cut the power as instructed. They installed the new anchor. The lead lineman than went up in the insulated bucket with the new guy line dangling from the bucket to the ground. The lineman in the bucket took hold of the overhead guy wire. This touched the 7,200 volt outer phase of the distribution lines which had not been de-energized. This contact energized the guy wire and electrocuted the employee. The ground employee heard sparks and used the lower bucket controls to override upper controls and bring the deceased employee out of the line. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The employees had been assigned to re-do a sectionalizer (electric conductor jumper) on a transmission line. According to the safety manager, the work procedure would be performed as live-wire bare-hand work. The two men ascended in a bucket. Employee B asked Employee A if he was ready and the answer was yes. Employee B then positioned the bonding cable over the electric conductor so as to bring up the grids and later began knocking out the sectionalizer jumper. At no time did he turn to see if Employee A, who was three feet west of him, had electrically connected the grids. He continued knocking out the sectionalizer. Employee A had not connected the grids and as the jumper clamp became loose, the jumper came off isolating the transmission line (69kv) in question. The jumper wire struck Employee A. The electrical current (because the grids were not connected) than conducted between the hot side of the sectionalizer through the grid band, through Employee A to the jumper and then to the load side of the transmission line. Employee A was electrocuted and Employee B suffered electrical burns to his hands. The bucket was lowered to remove the men. As this was being done, the transmission line was being lowered toward the bare-hand truck because the grid clamp was mechanically connected to the transmission line. The bucket was lowered until a dielectric breakdown occurred between the bucket and the bare-hand truck. This caused the over-current protection circuit to activate. Prior to this activation, the ground crew was exposed to serious electrical hazards. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: A lineman with 30 years experience was in the bucket of a bucket truck. He was elevated approximately 50 feet above the pole yard when he fell out of the bucket. There was no electrical contact as the power was not energized. At the time of the fall, he was attempting to tie off a new high line to a pole when he lost his balance and fell. He was not wearing a safety belt with lanyard attached to the boom or bucket and was killed instantly upon impact. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: Employees were erecting metal towers for a power sub-station. Two employees were working in an aerial tower bucket approximately 22' above ground. A loud pop was heard and the boom and bucket fell to the ground. Their safety lines held the two employees in the bucket. The deceased was jerked against the guardrails with such force that he bled to death internally within a short period of time. The other injured employee was admitted to the hospital with fractured legs and fractured foot. The end of the main hydraulic cylinder had stripped out and pulled apart allowing the boom to fall. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The deceased had taken a bucket truck in for repairs and had returned the next day to pick up the truck. When he tried out the aerial lift, it fell 25' with him in the bucket when the boom collapsed. He was operating the lift after being told by the mechanic that the work was not finished. The hydraulic cylinder on the boom was to be repaired. He was transported to a nearby medical center where he died. STANDARDS CITED RELATED TO THE INCIDENT: No citations were issued.
DESCRIPTION OF INCIDENT: The two employees had been assigned to change out a cross arm on an electric utility pole about 30 feet above ground level. While trying to maneuver the boom into position from the twin buckets of an aerial lift truck, the boom fell with the two men in the buckets. Both men remained in the buckets which fell some 30 to 35 feet to the ground. Both men died as a result of internal injures at the scene. The upper arm hydraulic lift cylinder failed allowing the buckets to fall 35 feet with the upper arm to the ground below. STANDARDS CITED RELATED TO THE INCIDENT: No citations were issued.
DESCRIPTION OF INCIDENT: The utility worker was being raised (he was operating the lift) in a bucket to change out a transformer and install new secondary wires. At some point during the lift, the controls in the bucket became jammed and the bucket was caught in the communication wires. The worker then asked the ground man to kill the power as the bucket was stuck and the controls jammed. The ground man mounted the truck, killed the power and looked up to see the deceased reaching out for the pole so as to be able to climb down to the ground. The ground man then jumped from the truck taking his eyes off the worker on the pole. The deceased hit the ground at the same instant having fallen 18-20 feet. He was taken to the hospital where he died eleven days later from internal injuries. STANDARDS CITED RELATED TO THE INCIDENT:
EQUIPMENT/MATERIAL/FACILITY RELATED
DESCRIPTION OF INCIDENT: The employee was working in an insulated aerial bucket near energized 7,200 volts power lines and some grounded de-energized lines. He was installing new lines which were de-energized and were in contact with the ground. The energized lines were temporary with pigtails protruding from the temporary connections. The bucket controls were outside the bucket on the side. The deceased failed to wear insulated gloves. He moved the bucket too close to the pigtail on one line. It contacted his hand and the control handle while he had his other hand on a grounded de-energized line. The resulting electrical shock was fatal. The bucket control cover was missing on the exterior mounted bucket controls and the upper control override button had been tied in the depressed position causing uncontrollable and unpredictable movement of the bucket. The bucket began to move sideways past the point where the operator intended it to stop and the employee holding on to the de-energized line with his left hand reached for the control handle just as the bucket moved into a "pigtail" of the temporarily located energized line which touched the deceased's hand. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The employee was using an aerial lift to reach the access plates on the underside of a bridge to close them off. He needed parts to do the job and requested the man below to get them. They obtained the necessary parts and called the employee on a hand radio to come down to pick them up. He got into the bucket which was located one foot below the bridge. The bucket was observed to start down and then stop. At some point he was pinned between the underside of the bridge and guard rail on the bucket crushing his head. The controls were not clearly marked and the employee was in a poor operating position. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The employee was riding aboard a personnel carrier (bucket) attached to an extended aerial boom 85 feet in length. He was inspecting structural members and the drainage system of an elevated interstate highway bridges over a river. He was located approximately 50 feet above normal ground level. It was determined that the boom extended 85' at an angle of 29° created a weight in excess of the 210 lbs. allowed with these conditions (the employee weighed 225 lbs.). The overload caused the outriggers to dig and sink into the soil (clay dirt) allowing the truck platform to tilt. This caused the extended boom and carrier to arc toward a bridge support column. During this downward thrust, the employee's head struck the column resulting in his death. STANDARDS CITED RELATED TO THE INCIDENT: No citations were issued.
DESCRIPTION OF INCIDENT: The employer was working at a power structure from an aerial bucket when a 3/8" shield wire he was working with and which was laying across the bucket came into contact with the upper controls and accidently activated the lower boom causing the boom to raise and go out. This put strain on the leveling rods and caused the bucket to flip into a horizontal position. The employee fell 56' from the bucket and was killed when his head struck an outrigger on the aerial lift vehicle. He was not wearing his safety belt with lanyard attached to the boom or bucket. The guard for the upper operating control was broken, thus allowing the control to be accidently activated by other equipment or materials. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: Employees were in the orchard pruning trees. The deceased was aloft in an aerial bucket when the upper connection of the hydraulic lift cylinder to the boom broke at the weld (a new, clean break) and the bucket fell approximately 21 feet with the employee in it. He was taken to a hospital where he died several hours later from trauma of the abdomen, chest and back, major tissue damage of vital organs and internal bleeding. STANDARDS CITED RELATED TO THE INCIDENT: No citations were issued.
DESCRIPTION OF INCIDENT: The employee was working from a "snooper" work platform (a cherry-picker style machine used to lower workers over the sides of bridges) sandblasting a bridge over a dam. The outrigger was not extended on the passenger side of the snooper truck and the interlock micro switches were not operable. When the employee swung the work platform 180 degrees to work on the other side of the bridge, the truck fell over the dam spillway 90 feet below. During the investigation, it was noted that the outrigger micro switch on the snooper side was ok. The outrigger micro switch on the drivers side was wired down. The turret micro switch on the passenger side was missing and the outrigger micro switch on the passenger side was defective. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: The employee was standing in an aerial work platform setting metal screws with a one fourth inch hand held electric powered drill in the ventilation system of a building. The employee was using a defective power cord. The grounding prong was missing and live parts were exposed on the cord. The employee slumped to the floor of the bucket when the motor on the lift was started and he could not be revived. Just as the motor started, he was heard to say "cut it off". The weather was hot and the employee very sweaty. It was possibly an electrocution although the employee had a history of asthma. STANDARDS CITED RELATED TO THE INCIDENT:
DESCRIPTION OF INCIDENT: There was no witness to the incident. The jobsite superintendent was found lying on the ground beneath the cherry picker whose bucket was 15 feet above the ground and positioned near the middle of the lot. The employee suffered multiple injuries and subsequently died the same day of the incident at the hospital. Occlusive coronary heart disease was noted. The cherry picker had a bucket on a 70 foot boom and a 650 lbs. capacity. It was being used to reach different heights of a three story building being erected. It was not known precisely what he was doing at the time of the incident. He did not have any tools in the bucket nor was he wearing his safety belt. The deceased had a triple heart bypass seven years prior to the incident. He was qualified to operate the aerial lift and had been employed by the firm 17 years. STANDARDS CITED RELATED TO THE INCIDENT:
See Appendix A (Table I) for a summary of cases by type of incident classification. Twenty-two of the 34 incidents or 65% were related to operating procedural problems. These included failure to take proper safety procedures around energized power lines, elevating or otherwise moving aerial platform (bucket/basket) into energized power lines, careless operation of the truck or vehicle on which the platform was mounted and failure to extend or extend properly the outriggers (stabilizers) among others. The top two categories (first two above) accounted for well over one-third (36% or 8 of 22) of the operational procedural problems within this type of incident classification. Eleven or 32% of the 34 cases were related to failure of equipment, material or facility related. These incidents included those where hydraulic cylinders operating the boom failed in over one fourth of the cases (3 of 11) of which one case resulted in two deaths. In a separate case, the upper connection of the hydraulic lift cylinder broke at a weld. Other classifications involved two cases where there were defective or inoperable controls. A separate case involved operator controls not being clearly marked as to function resulting in maneuvering errors. These four categories accounted for about two-thirds (7 of 11) in this type of incident classification. There were no cases that directly involved environmental conditions such as high winds, ice, snow etc. while the aerial devices were operating. The remaining case was classified as other and was related to a possible heart attack. The 34 incidents resulted in 35 deaths. See Appendix A (Table II). Summaries by types of accidents show that falls and contact with electric current (electrocutions) together resulted in four out of five of the fatal injuries. Falls accounted for 40% (14 of 35) of the fatalities. Five of these occurred when the boom failed (hydraulic cylinder related) and the employee fell with the platform. Five resulted from the overturn of the vehicle or truck on which the platform and boom were mounted. Free falls from the platform numbered three. One fatal accident occurred when the worker left the bucket and attempted to climb down the nearby pole when the controls jammed. See case 26. Not included in these fourteen deaths are four that occurred when the worker was electrocuted and then fell. Electrocutions (including electrocution followed by fall) resulted in 40% (14 of 35) of the deaths. These fatalities occurred when the worker came in contact with energized electrical lines or other sources of electricity while in the bucket except in the two cases that follow. One worker was out of the bucket and on a pole when electrocuted. One accident occurred when a worker on the ground touched a vehicle whose boom was in contact with overhead power lines. See cases 4 and 14. Other fatalities occurred when workers were pulled or thrown from the bucket when the truck was moving (four fatalities) and when crushed between parts of the platform and other surfaces (two). The remaining fatality resulted when the aerial rig tilted and the worker struck his head against a column. B. Employee Activity at the Time of Injury Appendix A (Table III) shows that the employees were performing normal work activities in 83% of the fatalities (29 of 35) involving such tasks as replacing light bulbs, working on power lines, trimming trees etc. Over one-half of these tasks involved work with or near electrical lines or other sources of electrical current during normal work activities. Other then normal activities or the activity could not be determined accounted for 11% and 6% respectively of the 35 fatalities. See Appendix A (Table IV) for locations of the workers at the time of the fatal incident. C. Standards Cited There were no citations in six of the 34 incidents. Section 5(a)(1) of the OSH Act was cited only once in a total of 77 citations. See Appendix B for a listing of relevant standards cited. Section 5(a)(1) of the OSH Act (General Duty Clause) which states that "each employer shall furnish each of his employees employment and a place of employment which is free from recognized hazards that are likely to cause death or serious harm to his employees" was cited once for the following reason: The employees were exposed to the unintentional movement of the aerial lift. The guard for the upper operating control was broken thus allowing the control to be accidently activated by other equipment or materials. IV. CONCLUSIONS A. Problem Areas Some problem areas concerning vehicle mounted elevating and rotating work platforms that suggest further need for standards development, modifications and enforcement are indicated below: There was exposure to electrical shock while working from aerial platform from failure to take proper precautions near energized electrical sources and when moving the platform (bucket/basket) in the vicinity of overhead power lines. Failure of the hydraulic cylinders on booms including attachment to boom (weld failures) resulted in the fall of the platform with the employee. The upper controls of the aerial device were not clearly marked or controls were defective or inoperable. Falls occurred when outriggers were not placed or placed improperly and equipment overturned. There were falls from lifts due to failure to provide and use safety belts attached to lanyards that were tied off to the boom or bucket. Workers were pulled or otherwise dislodged from the platform while the truck was in motion. B. Secondary Factors In the case report narratives, factors are mentioned that contribute to the incident and cut across all personnel aerial device accidents. They can be considered secondary causes and should be taken into account in any effort to reduce serious accidents. These include: Failure to understand and heed warnings. (see case 24) Lack of adequate lighting in area. (see case 16) Health problems of workers. (see case 34) Operating borrowed, unfamiliar equipment. (see case 15) C. Preventive Measures A review of the types of incidents and secondary factors illustrates that fatal incidents are complex events. Multiple points of attack are needed to address human, machine and environmental interactions resulting in fatal incidents. These preventive measure include: Establishment and strict enforcement of safety standards covering good safety procedures and practices in the use of aerial devices by workers at the worksite and at critical times, through tailgate discussions and direct supervision at the work location. These include measures to prevent falls and electrocutions. Improved preventive maintenance and regular maintenance procedures and frequencies to reduce equipment failure. Improved efforts in training and education through the use of required work and safety procedures and better knowledge of OSHA Safety Standards. Greater attention should be given to employees with language deficiencies. Improved supervision, particular for the new worker, in providing and requiring specific safety measures to be followed and emphasizing general safety awareness. Provide more information to the employers by way of consultation programs. In summary, deaths from falls with the platform when the boom failed, when the truck overturned with the worker in the platform and when the worker fell from the platform while aloft, resulted in 40% of the 35 fatalities. Deaths from electrocution resulting from contact with electrical current (overhead power lines, transformers, etc.) resulted in another 40% of the total. Included are electrocutions followed by a fall (4 fatalities). Two types of accidents, falls and contact with electric current (electrocutions) together accounted for four our of five of the fatalities included in this study. Other deaths occurred as a result of the worker being pulled, thrown, knocked etc. from the platform when the truck was in motion (11% or 4 of 35), crushed between the platform guards/parts and another surface (6% or 2 of 35) and striking head against surface when the aerial device tilted (3% or 1 of 35). Since well over a third of the fatalities were linemen (See Table V in Appendix A) utility companies should review safe work procedures with this category of workers on a more frequent basis than with other workers. Lineman have a greater exposure to falls and electrocutions. D. Data Source The OSHA Compliance Officer's case files resulting from accident investigations provide more detailed description of how occupational fatalities occur than any other data currently available to OSHA. This data source continues to be useful for studying the occurrence and nature of work fatalities when cases are aggregated by specific topics, e.g., by industry (oil/gas well drilling and services), by work activity (welding), by equipment used (ladders, scaffolds, etc.), by work location (confined work spaces) and so on. The information can then be analyzed further by various classification systems. Since the data are in-house, access is relatively easy. On the other hand, the uniformity, consistency and quality of the case file data used vary from narrative to narrative. The OSHA fatality/catastrophe codes in present use are too broad and are poorly defined in many instances. Occupational Safety and Health Administration, General Industry, OSHA Safety and Health Standards (29 CFR 1910), OSHA 2206, U.S. Department of Labor, 1978. Occupational Safety and Health Administration, Construction Industry, OSHA Safety and Health Standards (29 CFR 1926/1910), OSHA 2207, U.S. Department of Labor, 1983. American National Standards Institute, American National Standard for Vehicle-Mounted Elevating and Rotating Work Platforms, ANSI A92.2-1969 Classification of Variables Tables TABLE I Vehicle-Mounted Elevating and Rotating Work Platforms
TABLE II Vehicle-Mounted Elevating and Rotating Work Platforms
TABLE III Vehicle-Mounted Elevating and Rotating Work Platforms
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