Abstract: At approximately 2:00 p.m. on August 8, 1997, Employee #1, an ironworker, was part of a crew installing earthquake bridge deck support systems on a bridge over the Sacramento River near Woodland, CA. The crew was hanging under the bridge installing support beams that were being raised by a hydraulic crane to a point just beneath the bridge deck. Each beam weighed approximately 1,000 lb and consisted of two 12 in. by 13 ft wide C-channel beams with a 3 ft long by 2 1/2 ft wide by 1 in. high steel plate bolted between them near the center. The support beams were then stood across the top of the guardrails of an aerial boom lift. There was one employee in the manbasket as the lift moved each beam into position. The aerial lift was supported by planking placed between the main bridge support girders. Employee #1 was standing under a support beam, preparing to make the connection, when the pressure on the planking became too great and it folded, causing the boom of the lift to jerk and the support beam on the guardrails to topple and fall. The falling beam grazed Employee #1's chest and then struck his leg and foot, severely bruising his leg and amputating two of his toes and part of his foot. The aerial lift was rated for a maximum load of 500 lb for both people and materials, but it was carrying about 1,200 lb at the time of the accident. In addition, the support beam had not been secured to the lift while it was being transported.