WHILST TRAVELING IN CONSTRUCTION ELEVATOR EMPLOYEE WAS TAKEN TO THE 300 LEVEL ON ROUTE TO THE 230 FT LEVEL FOR MUD. AT THE 300 FT LEVEL HE WAS ENVELOPED IN STACK EMMISSION FUMES. HE LEFT FOR W ORK AT 12 PM AND BECAME ILL WITH A SORE THROAT. HE LATER DEVELOPED A SERIOUS MEDICAL CONDITION.