'THIS ACTION INVOLVES ISSUANCE OF A COMPLIANCE ORDER AND REPORTING REQUIREMENT TO SITHE MYSTIC LLC FOR OPACITY VIOLATIONS OF THE MASSACHUSETTS OPACITY STANDARDS INCLUDED IN ITS STATE IMPLEMENTATION PLAN. THE ADMINISTRATIVE ORDER REQUIRES SITHE TO CONDUCT OPACITY MONITORING, SWITCH TO USE OF LOWER-SULFUR FUEL ON THREE OF ITS FOUR UNITES. (UNITS 4, 5 AND 6) AND CONDUCT AN EXTENSIVE TESTING AND MONITORING PLAN.'