EMPLOYEE WAS WELDING ON THE GRAY FEEDER WHILE WEARING A WELDING HOOD. HE HAD SET HIS HARD HAT ON THE CONVEYER NEXT TO HIM. ANOTHER EMPLOYEE ACCIDENTLY IGNITED THE HAT. HE INHALED FUMES FROM TH E BURNING HARD HAT. THE INCIDENT OCCURRED ON JAN18, 2001, BUT WAS NOT REPORTED TO MANAGEMENT UNTIL 1-21-01 WHEN THE EMPLOYEE DECIDED TO SEEK MEDICAL TREATMENT.