Abstract: EMPLOYEE #1 CAME ON SHIFT JUST BEFORE THE ACCIDENT. THE PLANT LOG BOOK INDICATED THAT THE CHLORINATOR HAD BEEN FILLED WITH UNREACTED FERROUS CHLORIDE. EMPLOYEE #1 TURNED ON A SMALL AMOUNT OF CHLORINE GAS WHILE HE MEASURED THE LEVEL OF FERROUS CHLORIDE THROUGH THE CLORINATOR TOP OPENING. THE MEASUREMENT WAS TAKEN USING A FLOAT AND STRING. AS THE MEASUREMENT WAS BEING MADE, CHLORINE GAS BEGAN TO ESCAPE FROM THE TOP OPENING. EMPLOYEE #2 RESPONDED TO A CALL FOR HELP FROM EMPLOYEE #1. DURING THE RESCUE, EMPLOYEE #2 WAS EXPOSED TO CHLORINE GAS. INJURIES TO THE LUNGS WERE CAUSED BY INHALATION OF CHLORINE GAS. THE CHLORINATOR CONTAINED ALMOST FINISHED FERRIC CHLORIDE, WHICH REQUIRED A SMALLER AMOUNT OF CHLORINE TO FINISH THE PROCESS.