HOT SLAG BURNED A HOLE IN 02 LINE WHEN CUTTING METAL WITH OXYACETYLENE UNIT ABOUT 6"" BELOW FITTINGS, RESULTING IN 1ST & 2ND DEGREE BURNS TO LOWER RIGHT ABDOMEN AT BELT LINE. THE 2 X 3"" AREA OCCURED THROUGH 5 LAYERS OF CLOTHING, 4 OF WHICH WERE COTTON OR PARTLY COTTON. E.R. ADMINISTERED CARE & HAD HIM TAKE ONE DAY OFF.