EMPLOYEE WAS GRINDING IN THE REVOLVING FRAME WHILE WEARING A WELDING HOOD WITH A FLIP-UP LENS.EMPLOYEE BELIEVES THAT THE AIR CIRCULATION CAUSED BY THE REMOVAL OF WELDING FUMES USING SUCKER FANS AND AIR HORNS SUSPENDED METAL GRINDER PARTICULATES IN THE AIR. A METAL PARTICULATE ENTERED HIS MOUTH DURRING INHALATION. A CHIPPED TOOTH RESULTED WHEN HE CLOSED HIS JAWS.