Inspection Detail

Inspection: 303640890 - Diamond C Tower Service, Inc.

Inspection Information - Office: Oklahoma City Area Office

Investigation Summary

Employee #1 along with his foreman was in the process of landing a piece of tower structure to be added to the top of this communications tower, standing approximately 200 to 300 feet above ground level. While the two men were in the process of moving the section into position to be bolted into place, the hoist operator set the dogs on the hoist to hold the load in place while he dealt with a distraction that had just come up. Just after the hoist dogs had been set, and as the hoist operator was dealing with the distraction, the hoist line slipped. The hoist operator was close enough to the hoist to apply the hoist brake, thereby catching the structure before it fell to the ground. The sudden impact of the load on the hoist line caused the gin pole attachment mounted on the side tower near the top of the structure to break lose from the tower, while at the same time the tower section on the end of the hoist line swung into the side of the tower, causing the tower to tremble. At this time, Employee #1 starts coming out of the tower, supposedly thinking the tower was about to come down. While coming down out of the tower, Employee #1 falls off the tower some 200 plus feet to the ground. The job foreman also comes off the tower with no problem or injury. Both men were wearing the required fall protection equipment and were experienced tower erectors. The hoist operator was both the president of the company as well as the hoist operator, with several years experience in both hoist operation as well as tower erection. The hoist operator acknowledged that he had inspected, or at least looked over the hoisting equipment prior to his using the equipment. The owner of the hoist provided literature illustrating that the hoist had just been overhauled immediately prior to being brought to and used on this job. The hoisting equipment, including both the hoist and the gin pole, were already attached to the tower when this company arrived on site to replace a previous erection company who was removed from the job by the owner of the tower. The distraction listed above was caused by the previous company arriving on the job site only to see the Diamond C Company working on this tower. They were using the hoisting equipment without their knowledge of the change made by the tower owner and general contractor of the tower construction. It was concluded that the accident was caused by the hoist operator using the hoist brake to arrest the fall of the tower section, which caused the gin pole to break lose from the tower and the structure on the end of the hoist line to swing into the tower, sending strong vibrations throughout the tower, causing Employee #1 to think that the tower was about to come down. This tower was still standing several days after the accident as well as at the time the CSHO returned to the job site to finish the onsite investigation a day or so after the accident.

Keywords: GIN POLE, HOIST, STEEL ERECTION, FALL, FALL PROTECTION, CONCUSSION, TOWER