Abstract: At 2:55 p.m. on March 21, 2000, Employee #1 and coworkers were helping to build a dock for a new marine terminal in a large city. They worked for the general contractor and were finishing the concrete as it was being poured. A subcontractor had supplied a Thomsen concrete pump and placement boom, model TSS 50.14, pedestal serial #2185030732, boom serial #1785030607, along with an operator and assistant. During the course of normal operation, the articulating boom broke at the third section from the pedestal. The discharge end struck Employee #1 as it fell to the deck and came to rest upon his chest. He suffered a fractured hip, pelvis, and left arm; fractured fingers on his left hand and the ribs on his left side; a punctured lung; and a concussion. In April 1993, a crack had been found in the boom's top plate, extending into one of the side plates. Documentation indicated that this crack was very close to, if not in the same spot, where the boom's failure occurred. After the crack was discovered, the subcontractor, who owned the unit, consulted with the manufacturer. The manufacturer issued instructions for repair, provided a doubler plate to be welded to the side of the beam, and designated a weld shop to make the repair, which was completed in May 1993. On February 24, 2000, workers for the subcontractor visually examined the boom and found no problems in the area that ultimately failed. The manufacturer's written procedure for annual inspections of the boom called for visual inspection. Where visual inspection revealed questionable conditions, dye penetrants, mag particles, or x-rays were to be used to confirm any potential problems. One of the two workers who conducted the examination had attended the manufacturer's inspection class. No metallurgical examination of the failure area was made. Visual examination of the upper portion of the failed area revealed rust along the entire upper plate, extending down the side plates and including the doubler plate. A visual inspection alone would have indicated no sign of the previous repair of the crack on the inside of the rectangular boom section.