Abstract: At approximately 6:45 a.m. on June 14, 1990, Employee #1, a tractor equipment operator for Warren Smith Trucking, Inc., of Flagstaff, AZ, was downgrade in rural Sandoval County, NM, when the brakes on his belly dump tractor trailer automatically set. He had ruptured a triple valve, resulting in loss of air pressure in the braking system. A coworker pulled up about 10 ft behind him in another tractor trailer to assist. Both tractor trailers were loaded with gravel and were left idling without blocking the wheels. Employee #1 was between the second and third tractor wheels to back off his brakes when his coworker's truck rolled. The truck struck Employee #1's trailer, pushing it forward. The employee was caught and crushed between the tires before the trucks were stopped by his coworker. Employee #1 was killed.