DEFENDANT, PUBLIC SERVICE CO. OF COLORADO, INC. (COMANCHE), USES A PROCESS TO CLEAN ITS ELECTROSTATIC PRECIPITATORS WHICH EMITS OPACITY FROM ITS STACK AT 270% OF THE NSPS STANDARD. THIS PROCESS IS DONE FOR 2-3 DAYS EVERY 3-4 MONTHS. THE COLORADO AIR POLLUTION CONTROL DIVISION TOOK AN ENFORCEMENT ACTION WHICH RESULTED IN PAYMENT OF A SMALL PENALTY AND A DIRECTIVE BY THE COLORADO AIR QUALITY CONTROL COMMISSION (AQCC) TO TAKE NO FURTHER ENFORCEMENT ACTIONS. THIS DIRECTIVE WAS PREMISED ON AQCC'S JUDGMENT THAT DEFENDANT WAS ACTING RESPONSIBLY TO PLACE BAGHOUSES ON THE UNITS (YEARS IN THE FUTURE). EPA VIEWS AQCC'S DICISION AS A 'PERMIT TO POLLUTE' OR AT LEAST A VARIANCE, WHICH VIOLATES THE SIP.