Abstract: At about 1:30 p.m. on November 25, 2002, Employee #1, a maintenance worker, was installing a pair of collars on a shaft, which was a part of a conveyor on top of a hopper which measured 84 in. by 93 in. and was estimated to be about 15 ft deep. As directed by Employee #1, a coworker shut down the sand conveyor from the control panel and hung a tag on the switch. Employee #1 and the coworker had two-way radio communication with each other in case the production area ran out of sand. When sand stopped coming out of the bin, the coworker attempted to contact Employee #1 over the radio, but received no response. The coworker also could not find employee #1 in the hopper area where he was expected to be working. When a second coworker began to bang on the lower part of the hopper to restart the flow of sand, Employee #1's feet came out of the hopper's discharge port. Rescue attempts failed and Employee #1 died of asphyxia.