A material handler operator was moving recycling material. When the operator let go of the material, the grapple swung back in the other direction. A piece of pipe flew from the grapple, striking an employee on the back of her hard hat. The employee fell to the ground and lost consciousness. The employee sustained a right parietal scalp injury, frontal brain hemorrhage, and T1 and T3 spinous process fractures. The employee was hospitalized.