THE COMPLAINT ALLEGE THAT AT 9:00AM ON DECEMBER 19, 1997, A RELEASE OF CHLORINE, WHICH IS A CERCLA HAZARDOUS SUBSTANCE AND AN EPCRA EXTREMELY HAZARDOUS SUBSTANCE, GREATER THAN ITS REPORTABLE QUANTITY OF TEN POUNDS, OCCURRED FROM SUN'S MARCUS HOOK FACILITY, MARCUS HOOK, PENNSYLVANIA. THE FACILITY IS LOCATED IN BOTH THE COMMONWEALTH OF PENNSYLVANIA AND THE STATE OF DELAWARE. THE RELEASE RESULTED FROM THE ERRONEOUS OFFLOADING OF SODIUM HYPOCHLORITE INTO A TANK OF ZINC SULFATE, THE SUBSEQUENT RESULT BEING THE CREATION AND RELEASE OF CHLORINE GAS INTO THE ATMOSPHERE. THE NRC WAS NOT INFORMED OF THESE RELEASE UNTIL APPROXIMATELY 71/2 HOURS AFTER SUN HAD KNOWLEDGE THAT A RELEASE EXCEEDING THE RQ OCCURRED, IN VIOLATION OF SECTION 103 OF CERCLA. NEITHER THE STATE EMERENCY RESPONSE COMMISSION'S NOR THE LOCAL EMERGENCY PLANNING COMMITTEE'S OF POTENTIALLY AFFECTED STATES AND LOCALITIES WERE NOTIFIED IMMEDIATELY OF THE RELEASE NOR PROVIDED WRITTEN FOLLOW UP AS SOON AS PRACTICABLE CONCERNING THE RELEASE AS REQUIRED BY THE PERTINENT PROVISIONS OF SECTION 304 OF EPCRA.