Document VGzwERY47dO3p2yNL3yxYXK6j

ABD00076946 VCM RELEASES FROM THE OLD MODULE BLOWDOWN TANK SAFETY RELIEF VALVE ON APRIL 3, 1980 AND APRIL 7, 1980 Summary: These releases occurred because the old module blowdown tank was rated for only 66 psig whereas some of the systems feeding the blowdown tank operate normally at 70 to 80 psig. In this situation, any malfunction in the emission recovery system which removed vapors from the blowdown tank or an excessive VCM feed rate could quickly lead to overpressuring the tank. This tank has now been replaced with two new vessels with design pressures of 150 psig so that this type of problem can no longer occur. Details on the corrective steps which were taken to prevent any more VCM releases from this source are included in the answer to Question 2. QUESTION 1: FOR EACH RELIEF VALVE OR MANUAL VENT VALVE DISCHARGE OF VINYL CHLORIDE ("VC") WHICH OCCURRED FOR THE PERIOD FROM JANUARY 1, 1979 TO JANUARY 1, 1985, A DESCRIPTION OF THE NATURE AND CAUSE OF THE DISCHARGE, INCLUDING PRIMARY AND/OR RELATED CAUSE(S). Response: Descriptions of these incidents are provided in the documents which are referenced below: April 3, 1980 1. This incident was reported in a letter to Rebecca Hanmer, Region IV EPA dated April 8, 1980 which is attached as reference D-l, Appendix D. April 7, 1980 1. This incident was reported to Rebecca Hanmer, Region IV, EPA in a letter dated April 16, 1980 which is attached as reference D-2, Appendix D. QUESTION 2: FOR EACH DISCHARGE DESCRIBED IN RESPONSE TO III.A.l., A DETAILED DESCRIPTION OF ALL RELEVANT CORRECTIVE STEPS TAKEN BEFORE AND DURING EACH DISCHARGE TO PREVENT AND/OR MINIMIZE THE RELEASE OF VC TO THE ATMOSPHERE, INCLUDING, BUT NOT LIMITED TO, SUCH STEPS AS REROUTING VC EMISSION VENTS TO A COLLECTION VESSEL OR INCINERA TOR. * -33- ABD00076947 Response: The relevant corrective steps taken before and during the April 3, 1980 and April 7, 1980 releases are discussed in the references provided under Question 1. The information provided below and documented in the listed references is additional information relevant to corrective steps that were taken before and after these incidents. ADDITIONAL DETAILS ON CORRECTIVE STEPS THAT WERE TAKEN BEFORE THE APRIL 3, 1980 RELEASE Operating procedures were written and issued to provide the operators with guidelines to prevent operating problems. A copy of the operating procedure dated April 27, 1979 is attached as reference D-3, Appendix D. ADDITIONAL DETAILS ON CORRECTIVE STEPS THAT WERE TAKEN AFTER THE APRIL 3, 1980 RELEASE The shift operators were trained in the blowdown tank operating procedures. A record of the training of one of the shifts dated 4/6/80 is attached as reference D-4, Appendix D. Normal plant practice would have called for the operators on the other shifts to have also been trained. However, records of this training have not been located. ADDITIONAL DETAILS ON CORRECTIVE STEPS THAT WERE TAKEN AFTER THE APRIL 7, 1980 RELEASE A new batch waste water stripping system was installed and put into operation in July 1981. Notification of the startup of this stripper was given to Rebecca Hanmer, EPA Region IV, in a letter dated June 1, 1981 which is attached as reference D-5, Appendix D. This stripping system replaces the old blowdown drum which was taken out of service. Since the new stripper has a design pressure of 150 psig it is not subject to the type of problem which caused these releases. A -34-