Abstract: On April 29, 1990, Employee #1, a welder-boilermaker for a Pennsylvania tank erection company, was installing the roof sheets on the last of four tanks erected on the premises of a chemical plant in Patterson, NJ. Employee #1 was standing on a single-plank platform of a tubular welded steel scaffold tower which had been erected in the center of a 40 ft diameter outside storage tank (tank #4). He was fitting and tack welding the sheets to a hanging ring that was standing on planks on two sides of the guardrails. When the scaffold tower kicked back and collapsed against the inside tank wall, Employee #1 fell forward with the steel ring 33 ft to the base. One of two welded roof sheets then broke loose and fell into the tank, also striking Employee #1. He died.