Document KRvOKEb2g3aJwqOvmzjBkvyMr

April 6, 1979 ABDOO190369 Conoco Chemicals Contmr>nt;il Oil Company P 0 Bo^ 9'. New H'y'iwny 29 Aberdeen. Mississippi 39730 Mr. Tommie A. Gibbs Chief, Air Engineering Branch United States Environmental Protection Agency Region IV 345 Courtland Street, N.E. Atlanta, GA 30308 Dear Mr. Gibbs: A "Leak Detection and Elimination Program1' for the Conoco Chemicals Company PVC Plant at Aberdeen, Mississippi, was submitted on May 9, 1977, and was approved by your office on June 30, 1977. Wc have revised that program to accomplish the following: Lower the continuous monitoring system action level defining a leak to 5 ppm vinyl chloride in all cases. Establish a specific and standardized procedure for routine leak patrols. Convert from the use of Century OVA portable hydrocarbon detectors to HNU portable hydrocarbon detectors. Update the continuous monitoring system sample locations. Plant and industry experience with the MNU portable hydrocarbon detector shows it to be reliable in vinyl chloride service and it is simpler, more rugged, and requires less maintenance than the Century OVA. Approval of this revised "Leak Detection and Elimination Program" is requested prior to its issue in the plant. Sincerely, R. A. Frohrcich Chief Process Engineer if Attachment B/C: CLM, ELK(4), SJV, AHS, MCJ, JRM, VEM, JPW, PAK