Employees were welding a wall plate to connect a structural steel member. The base of the member became unstable, and the structural steel started to fall, causing an employee sitting on a cross member to fall 15 feet to the ground below. A second employee was welding while standing in an aerial lift basket when the structural steel member fell and crashed down on the lift, slamming it to the ground. The employee suffered multiple blunt force trauma injuries and was hospitalized.