An employee was working at an electric arc furnace. The employee was cleaning ash and shoveling it down a 3-by-3-foot electrode mast hole to the level below. The electrode mast hole did not have an electrode in it due to the furnace being shut down at the time. The employee fell through the hole approximately 20 feet. The employee suffered fractures to their left shoulder, pelvis, L1, L2, and L3 vertebrae; and S1, S2, and S3 sacral bones.