Abstract: Employee #1, a heavy equipment operator for Clark Construction Company, died when he was struck by a crane boom. At the time of the incident, four employees were removing a 21 foot section of an 84 foot boom of a link-belt crane. The four employees present were a superintendent, who was also the crane operator, a welder, a drill tender, and a heavy equipment operator. The welder was standing to the front of the boom in line with the crane operator. The drill tender and the heavy equipment operator were under the boom which suspended approximately 5.5 feet above ground level. The superintendent was also certified as a crane operator and was at the controls of the crane holding the boom in the suspended position while his employees were removing the carter keys. The welder was knocking the pins out with a sledge hammer. The boom was not supported, blocked nor was any cribbing used to support the boom while employees were working underneath the boom knocking the pins out. When the welder knocked the second pin out from the under-side, the boom collapsed striking Employee #1 killing him. The operator's manual has a well illustrated and written instruction on the proper way to remove a section of the boom.