Abstract: On December 20, 2007, Employee #1 was working for Timec, a contractor that was hired to remove all non-hazardous waste from the Shell Oil refinery in Martinez, CA. At approximately 2:00 p.m., he was backing a Shell-owned waste disposal truck, #MT133 and referred to as a lugger, up to a non-hazardous waste disposal pit to dump the waste into a larger roll-off container. This container sat in a concrete depression with a 10 in. tall lip around it. Employee #1 raised the hydraulic arms of the lugger to lift the trash vertically. The trash was supposed to slide off by the force of gravity into the roll-off container, but it became jammed in the lugger. Employee #1 got out of the cab of the truck to clear the jam. He was walking over to the larger container when he tripped over the 10 in tall lip and fell approximately 6 ft 6 in. to the rounded bottom of the roll-off. Employee #1 suffered a bone chip near his spinal column and was transported to the hospital, where he underwent surgery the next day. Later during treatment, he suffered a mild heart attack. The causal factors for the accident include: (1) absence of a guardrail or barrier in front of the approximately 6 ft 6 in. deep concrete depression; (2) Employee #1 being unaware of the unguarded fall hazard; (3) the failure of the trash inside the lugger to fall consistently into the roll-off container; and (4) the absence of an established procedure for when the trash does become jammed.