Abstract: At approximately 4:30 p.m. on July 13, 2009, Employee #1 was delivering a load of gravel with a semi-tractor and end-dump trailer at a highway work zone construction stockpile and staging area located adjacent to the southbound lane of a two-lane rural highway. There was no eye witness(s) that actually observed what happened and no other persons were in the stockpile area at the time of the event. The vehicle was discovered by a passerby who noticed the semi-tractor and end dump on its side, facing north, with Employee #1 on the ground beneath the open driver-side door of the semi-tractor cab. Employee #1 apparently positioned the vehicle towards the northwest side of the stockpile yard, on loose soil and gravel that was significantly sloped and likely, the tandem wheels of the end dump trailer were not placed even nor were the trailer brakes engaged. Apparently when the dump cycle was initiated and the hydraulic boom was raised to about three-quarters capacity, the end-dump trailer became less stable when the center of gravity of the load offset enough to cause the semi-tractor and end dump trailer to flip over. Employee #1 apparently was positioned outside the open driver-side door of the cab of the semi-tractor cab while operating the end-dump controls. When the vehicle flipped, Employee #1 was crushed between the ground and the cab. Employee #1 was killed.