Abstract: Employee #1 was helping two coworkers dismantle a crane boom on a crawler crane. The crane operator had driven the crane to a remote area in order to dismantle the boom, which was laid down to within 18 in. of the ground. The load block had been removed when the foreman called for Employee #1 and the two coworkers to come back to the intersection and operate a D-3 dozer to spread base material. About an hour later, the three employees returned to the crawler crane to continue dismantling the boom. The crane operator was using a sledgehammer to remove the bottom two pins from the first head section of boom. He knocked out one pin and was knocking out the other one when Employee #1 asked if he could do it. Employee #1 prematurely removed a pin holding a boom section, causing the boom to fall on him, killing him. The boom had not been properly blocked and the suspension ropes had not been relocated as they should have been according to the operator's manual.