THE WORKER WAS DUMPING THE EXTRA DUST BY OPENINGA SMALL PORTHOLE ON THE SIDE OF THE SCREEN AND LETTING THE DUST POUR OUT INTO A HOPPER ATTACHED TO A FORKLIFT. WHEN THE HOPPER WAS FULL HE NEEDE D TO CLOSE THE PORTHOLE DOOR. HE STOOD ON THE FRONT FENDER, PUT HIS RIGHT FOOT ON THE EDGE OF THE HOPPER AND CLOSED THE DOOR. HE STUCK HIS FOOT AND LOWER LEG IN HOT DUST.