Abstract: EMPLOYEE #1 AND A HELPER (TRAINEE) WERE CLEANING A 40 FOOT OVER-THE-ROAD TANKER. THE TANKER HAD LAST CONTAINED LIQUID CORN SYRUP. A HOT WATER FLUSH WAS NOT AVAILABLE SO THE EMPLOYEES USED CAUSTIC SODA (NAOH) TO CLEAN THE TANK. THE TIME WAS APPROXIMATELY 5:40 PM. AFTER THE CLEANING PROCESS WAS COMPLETED, THE TRAINEE WENT HOME. EMPLOYEE #1 THEN ENTERED THE TANKER TO CHECK FOR ANY CORN SYRUP RESIDUE. HE WAS IMMEDIATELY OVERCOME BY CARBON MONOXIDE GAS. ANOTHER EMPLOYEE (A MECHANIC) MISSED EMPLOYEE #1 AND BEGAN TO SEARCH FOR HIM. HE WAS FOUND LYING FACE-UP IN THE TANK. THE MECHANIC AND ANOTHER EMPLOYEE WERE ABLE TO RESCUE EMPLOYEE #1. EMPLOYEE #1 WAS TAKEN TO A LOCAL HOSPITAL WHERE THE DIAGNOSIS WAS CARBON MONOXIDE POISONING. THE EMPLOYEE WAS ADMITTED TO THE HOSPITAL FOR TREATMENT.