US WSET COMMUNICATIONS, INC. AND US WEST BUSINESS RESOURCES, INC. RESPECTIVELY OWN AND OPERATE A TELECOMMUNICATIONS COM- PLEX (PLAZA CAMPANA) IN ALBUQUERQUE, NEW MEXICO WHICH IS A TELEPHONE SWITCHING AND COMPUTER OPERATIONS FACILITY. AT THE TIME THE FACILITY WAS CONSTRUCTED IN 1979 AND 1980, AND A- GAIN IN 1983 AND 1889, LARGE DIESEL-DRIVEN GENERATOR STA- TIONS WERE INSTALLED IN THE BASEMENT OF THE COMPLEX FOR THE PURPOSE OFEMERGENCY BACKUP POWER AND, POTENTIALLY, TO SUP- PLEMENT PEAK POWER REQUIREMENTS FOR THE ALBUQUERQUE AREA. US WEST INSTALLED THE GENERATION EQUIPMENT WITHOUT OBTAINING A PERMIT, AND OPERATED THE EQUIPMENT ON A LIMITED BASIS WITH- OUT A PERMIT FROM 1980 UNTIL 1989. THE POTENTIAL EMISSIONS OF THE ENGINES IN OPERATION WERE CALCULATED VARIOUSLY BY THE STATE OF NEW MEXICO, EPA AND US WEST, AND ARE DESCRIBED IN DETAIL, BOTH IN THE ATTACHED COM- PLAINT AND IN A SEPT. 30, 1993 MEMORANDUM REVIEWING THE CASE AND DESCRIBING POTENTIAL LITIGATION RISK. ALTHOUGH THE ACT- UAL EMISSIONS WERE A TINY FRACTION OF THE THRESHOLD FOR AP- PLICABILITY OF PSD REGULATIONS TO THE FACILITY, IT WAS EPA'S POSITION THAT, UNDER 40 C.F.R. SEC. 52.21 AND 52.24, PO- TENTIAL EMISSIONS BY THE FACILITY, CALCULATED BY EITHER PARTY, MADE IT SUBJECT TO THE REGULATIONS AS A MAJOR STAT- IONARY SOURCE . BASED ON THE RESPONSE TO A JUL. 24, 1989, INFORMATION REQUEST BY EPA AND THE INSPECTIONS OF THE FACIL- ITY, IT WAS CONFIRMED THAT US WEST H