Abstract: EMPLOYEE #1 WAS OPERATING A CHEMICAL REACTOR USED IN THE MANUFACTURE OF A HERBICIDE INTERMEDIATE DESIGNATED AS A.D.D. AN EXPLOSION OCCURRED AFTER A LENGHTY SOLVENT REMOVAL PROCEDURE IN WHICH THE DESIRED FREEZE POINT COULD NOT BE REACHED. THE EMPLOYEE WAS TOLD A FEW MINUTES BEFORE THE EXPLOSIION TO SHUT DOWN AND COOL THE REACTOR. THE STAGE OF THE SHUT-DOWN, AND HIS PHYSICAL LOCATION AT THE TIME OF THE EXPLOSION ARE NOT KNOWN. EMPLOYEE #1'S LEGS WERE BLOWN OFF. HE IS STILL IN A COMATOSE STATE. THE REACTOR WAS NOT EQUIPPED WITH AUTOMATIC CONTROLS. THE CASUAL FACTOR IS BELIEVED TO BE THE OVERHEATING OF THE MATERIAL IN THE REACTOR TO THE POINT WHERE IT BEGAN A SELF-SUSTAINING THERMAL DECOMPOSITION.