BRIMHALL SAND, ROCK AND BUILDING MATERIALS ( BRIMHALL ) OPERATES AN ASPHALT PLANT IN SNOWFLAKE, ARIZONA. UNDER REGULATIONS KNOWN AS NEW SOURCE PERFORMANCE STANDARDS OR NSPS, PROMULGATED BY THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY ( EPA ), THIS PLANT'S EMISSIONS INTO THE ATMOSPHERE MUST NOT CONTAIN MORE THAN 90 MG/DSCM (0.04 GR/ DSCF). SOURCE TESTS CONDUCTED AT THE SITE SHOW THAT THIS STANDARD HAS BEEN EXCEEDED ON THREE SEPARATE OCCASIONS. EPA DISCOVERED THESE EMISSION VIOLATIONS EARLIER THIS YEAR AFTER RECEIVING A CONGRESSIONAL INQUIRY REGARDING THIS FACILITY. BECAUSE THE STATE OF ARIZONA, THROUGH THE ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY ( ADEQ ), HAS BEEN DELEGATED THE AUTHORITY TO ENFORCE THE PROVISIONS OF NSPS APPLICABLE IN THIS CASE, EPA CONTACTED ADEQ ABOUT THE FACILITY. MIKE HOWETH OF THE FLAGSTAFF OFFICE TOLD EPA THAT BRIMHALL HAD FLUNKED SEVERAL SOURCE TESTS AND REFERRED EPA TO ADEQ'S PHOENIX OFFICE TO GET COPIES OF THE TESTS. DAN WILLIAMS OF ADEQ'S PHOENIX OFFICE FORWARDED COPIES OF ADEQ'S REVIEW OF THE RELEVANT SOURCE TESTS. THE SOURCE TESTS, WHICH HAD BEEN ORDERED BY ADEQ, SHOWED THAT SINCE THE ASPHALT PLANT HAD BEEN IN ARIZONA, THE PLANT HAD NEVER BEEN IN COMPLIANCE. (THE PLANT HAD BEEN BUILT IN 1981 AND ORIGINALLY SET UP IN CALIFORNIA. BRIMHALL PURCHASED THE PLANT IN 1988 AND MOVED IT TO SNOWFLAKE). AFTER HE RECEIVED THE SOURCE TESTS, ST