Employees were trying to remove a guardrail so they could replace a concrete sidewalk. One of the guardrail's bolts was
stripped and would not come out. A skid steer did not succeed in removing the bolt, so they released the pressure from the guardrail. The bolt then came loose, causing the guardrail to pop up and hit one of the employees on the chin. He suffered a neck injury and was knocked unconscious, then had trouble breathing after waking up. He was hospitalized.