Abstract: ON THURSDAY, MARCH 1ST, 1984, AT APPROXIMATELY 1 PM, SEVERAL EMPLOYEES OF FIVE DIFFERENT SUBCONTRACTORS WERE OVERCOME BY A GASEOUS DISCHARGE WHICH WAS LATER IDENTIFIED AS SULFER DIOXIDE. THE EMPLOYEES WERE OVERCOME WHILE WORKING AT THE CORN PRODUCTS SITE. MOST OF THESE EMPLOYEES WERE WORKING OUTSIDE THE PLANT BUILDING ON THE NORTH SIDE. SEVENTEEN EMPLOYEES WERE TAKEN TO THE HOSPITAL AS A RESULT OF THIS FIRST EPISODE. AT APPROXIMATELY 3 PM ON THE SAME DAY, A SECOND INCIDENT OCCURRED, SIMILAR TO THE FIRST. THIRTEEN EMPLOYEES WERE TAKEN TO THE HOSPITAL. AS A NORMAL PART OF THE CORN PRODUCT MANUFACTURING PROCESS, SULFER DIOXIDE IS MIXED WITH WATER TO FORM A RINSE MIX FOR CORN STORED IN STEEPS (100 FOOT TALL SILOS). THE SULFER DIOXIDE IS STORED UNDER PRESSURE (AS A LIQUID). IT IS REMOVED FROM STORAGE THROUGH A CLOSED SYSTEM. THE PRESSURE IS REDUCED AND THE SULFER DIOXIDE BECOMES GASEOUS AND MIXES WITH WATER TO FORM THE RINSE MIX. CORN PRODUCTS OFFICIALS DISCOVERED THAT AT ONE PM ON MARCH FIRST THE WATER VALVE DID NOT OPEN TO PROVIDE THE WATER FOR THE RINSE MIX. (THIS IS A COMPUTER CONTROLLED OPERATION, SO THE MALFUNCTION WAS NOT IMMEDIATELY NOTICED.) AS A RESULT, 500 POUNDS OF SULFER DIOXIDE GAS WAS RELEASED THROUGH THE STEEP AND INTO THE ATMOSPHERE. WATER WAS RELEASED DURING THE THREE O'CLOCK RINSE, BUT GAS AGAIN ESCAPED, PROBABLY BECAUSE SULFER DIOXIDE LEFT OVER FROM THE ONE PM RINSE WAS PUSHED OUT THE TOP OF THE STEEP BY WATER FROM THE THREE PM RINSE.