Abstract: A two piece dry well unit was being lifted from the delivery truck in an excavation. Employee #1 was riding inside the truck with the unit into the excavation. Three chains and an O-ring were used to rig the 2500 pound unit. Chains with hooks were used to hook onto the base lifting device of the unit. The O-ring attached to the hook on the crane boom of the truck. As the dry well unit was being lowered from the truck, the O-ring that had been welded broke. The base of the dry well unit hit the end of the truck bed and dropped straight down causing the top section to crumble, pinning Employee #1 in the excavation.