Abstract: On October 25, 1990, Employee #1, a longshoreman, was a member of a gang unloading coils of wire from a barge using a shore-based American, model 999, 110-ton crawler crane rented from an adjacent tow-barge company. The yard that sold the crane 6 months earlier did not have a 110T boom available and fitted what they thought was a 250T boom on the crane. In fact, the boom was a guy derrick boom, not a lift crane boom, an unauthorized configuration for which a load rating chart does not exist. The surveyor of the certifying company did not detect the unauthorized configuration, nor did it inspect under the rubber "rub wraps" on the upper lacings in the top section of the boom. The boom failed while unloading a draft of 17 wire coils and struck and killed Employee #1. After the accident, serious oxidation of the lacings under the rub wraps was found, in some cases rusted through with pin holes. A computed lift weight of more than 50,000 lb and a position that was off level by 5 degrees combined to overload the already weakened boom. The relative location of the dropped draft and the failed boom indicates side loading of the boom.