BY LETTER DATED MARCH 13, 2000, CABOT INITIALLY DISCLOSED TO THE ENVIRONMENTAL PROTECTION AGENCY, REGION III (EPA) POTENTIAL VIOLATION SOF THE CLEAN AIR ACT ( CAA ). EPA THEN SENT A REQUEST TO CABOT SEEKING ADDITIONAL INFORMATION REGARDING THE SELF-DISCLOSED VIOLATIONS, TO WHICH CABOT RESPONDED BY LETTER DATED JUNE 30, 2000. THE INFORMATION PROVIDED BELOW WAS OBTAINED FROM EPA'S REVIEW OF THE MARCH 13, 2000, AND THE JUNE 30, 2000 LETTERS. AS PART OF ITS OPERATIONS IN ITS RESEARCH AND DEVELOPMENT PILOT PLANT (BUILDING 98), CABOT OPERATES A HYDROCHLORIC ACID SCRUBBER. THE FEDERALLY ENFORCEABLE STATE OPERATING PERMIT (FESOP) FOR THIS SCRUBBER (PADEP PERMIT NO. 46-313- 006E) REQUIRES, AMONG OTHER THNIGS, CABOT TO MAINTAIN AT LEAST 3 GRAMS OF CAUSTIC PER LITER OF SOLUTION IN THE SCRUBBER AND TO MONITOR THE CAUSTIC LEVELS IN THE SOLUTIONS AT LEAS DAILY. CABOT MAINTAINED A LOG FOR RECORDING INFORMATION CONCERNING OPERATION OF THE SCRUBGER, INCLUDING THE DAILY CAUSTIC LEVELS. WITHIN A FIVE MONTH PERIOD, FROM THE END OF SEPTEMBER 1999 UNTIL THE WEEK OF FEBRUARY 29, 2000, THE SUPERVISOR RESPONSIBLE FOR MONITORING AND RECORDING SCRUBBER PERFORMANCE DATA FAILED TO RECORD THE SCRUBBER SOLUTION CAUSTIC LEVELS FOR APPROXIMATELY 37 DAYS; INSTEAD, THE SUPERVISOR NOTED IN THE LOG THAT THE PRODUCTION UNTI WAS NOT IN OPERATION. THE ACTIVITIES OF THE SUPERVISOR WERE DISCOVERED AS PART OF A ROUNTIN