Abstract: Employee #1, a laborer, was preparing to hook up a piece of guardrail for removal. A coworker, the excavator operator, had just set a guardrail post down at its new location. The coworker backed the excavator up 9 ft 3 in. and asked Employee #1 if he had clearance from the light pole along the shoulder of I-695 (to the driver's right). Employee #1 apparently signaled the coworker to swing the boom toward the pole. The coworker asked Employee #1 again if he had clearance from the light pole, and Employee #1 signaled him a second time to swing the boom. With the boom folded in half and its shovel curled inward, the coworker swung it toward the light pole. The elbow of the excavator's boom struck the pole and knocked it into the right and center lanes of traffic on the I-695 outer loop, where it was struck by a passing dump truck and driven back into the roadside work area. It struck Employee #1, and he fell approximately 4 ft into the shallow end of the excavation and alongside the excavator. Employee #1 sustained a fractured skull, a broken leg, and multiple contusions on his back. He was transported by helicopter to Maryland Shock Trauma, where he was listed in critical condition. Subsequent investigation revealed that the coworker was relying on signals given by Employee #1 and went against his own judgment, based on 28 years of experience operating heavy equipment. If he had known that he had clearance, he would have backed the excavator up another 10 ft before swinging it to the right.