What was found
(CAN) AT THE GATE, CREW TURNED ON BOTH AIR CONDITIONING PACKS AND SMOKE/AND OR HAZE ACCOMPANIED BY ODOR BEGAN TO FILL THE COCKPIT AND CABIN. CREW IMMEDIATELY OPENED THE MAIN CABIN DOOR TO VENT THE AREA, AND SMOKE/HAZE BEGAN TO DISSIPATE. MAINTENANCE FOUND A MAJOR OIL LEAK FROM THE COMPRESSOR SECTION OF THE APU. OIL WAS INJESTED IN TO ONE OR BOTH PACKS. NEW APU INSTALLED. BOTH CONDENSOR BAGS REPLACED AND DUCTS CLEANED OF OIL. INFORMATION WILL BE UPDATED WHEN ROOT CAUSE OF LEAK IS AVAILABLE. (TC NR 20060816003)