ARCO OIL AND GAS COMPANY OWNED AND OPERATED THE RIVERTON DOME GAS PLANT IN RIVERTON, WY FROM 1963 TO FEB. 27, 1993. SNYDER OIL THEN PURCHASED AND OPERATED THE PLANT FROM FEB. 27, 1993 TO PRESENT. ARCO MADE 2 MAJOR MODIFICATIONS AND VIOLATED THE PREVENTION OF SIGNIFICANT DETERIORATION(PSD) BY NOT OBTAINING THE NECESSARY PSD PERMITS. SNYDER BECAME THE OWNER AND OPERATOR ON FEB. 27 AND HAS NOT OBTAINED A PERMIT FOR THESE EMISSION SOURCES-THERFORE HE IS ALSO IN CONTINUOUS VIOLATION OFF 40 C.F.R 52.21 (B)