INJURED PERSON WAS REFUELING A DIESEL TANK FOR A PORTABLE PUMP ENGINE. THE GROUND HAD A LAYER OF FROST ON THE GRASS AREA. HE SLIPPED WHILE MOVING AROUND THE PUMP ENGINE. HE CAUGHT ALL HIS WEIGHT ON HIS LEFT HAND AND SPRAINED HIS LEFT WRIST (THE WRIST HAD BEEN INJURED PREVIOUSLY IN A NON WORK-RELATED ACCIDENT).