Abstract: THIS INCIDENT (EXPOSURE TO HYDROGEN SELENIDE GAS) LED TO THE HOSPITALIZATION OF ONE EMPLOYEE AND THE TREATMENT AND RELEASE OF TWO OTHERS. THE COMPANY STRIPS THE SELENIUM COATING FROM ALUMINUM CORE DRUMS IN A GRINDING OPERATION. THE DRUMS HAVE BEEN USED IN THE PHOTO COPY INDUSTRY. THE STRIPPING PROCESS UTILIZES A WATER BASED COOLANT AND PRODUCES A SLUDGE, PRIMARILY COMPOSED OF SELENIUM AND ALUMINUM. A SCRAPPER, AUGER TYPE, USED TO TO SEPARATE THE AQUEOUS PHASE FROM THE SLUDGE, WAS REMOVED FROM THE PROCESS AND PLACED IN A REMOTE PORTION OF THE PLANT. AFTER APPROXIMATELY 3 MONTHS THE SCRAPPER, COATED WITH DRY SLUDGE, BEGAN TO SOUR, EMITTING AN OFFENSIVE ODOR. EMPLOYEES WERE INSTRUCTED TO MOVE THE UNIT OUTSIDE AND CLEAN THE SLUDGE FROM THE SCRAPPER. THE SLUDGE WAS REMOVED AND PLACED INTO A BARREL. WATER WAS ADDED. THE WATER REACTED WITH THE SLUDGE, PRODUCING HYDROGEN SELENIDE GAS. EMPLOYEE #1 DOUBLED OVER, EXTREMELY NAUSEAS, AND COUGHED EXCESSIVELY FOR ABOUT 20 MINUTES. THE SYMTOMS SUBSIDED UNTIL, ABOUT 6 HOURS LATER, PULMONARY EDEMA OCCURRED. THE EMPLOYEE WAS ADMITTED TO THE HOSPITAL WITH AN ARTERIAL BLOOD GAS LEVEL OF 38% OXYGEN.?? THE COMPANY WAS INSTRUCTED TO IMPLEMENT EMERGENCY PROCEDURES, COMPOSED OF TRAINING AND NEUTRALIZATION OF THE SLUDGE WITH SODA ASH. THIS WAS THE FIRST TIME THE COMPANY HAD HAD SUCH AN INCIDENT.