As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LGA - DURING CRUISE AT FL 370 A BLUE HAZE APPEARED IN CABIN. DESCENDED TO FL 330 AND TURNED OFF HIGH PRESSURE BLEEDS AND BLUE HAZE DISSIPATED. FOUND APU LEAKING OIL. PLACARDED APU INOPERATIVE PER MEL. REPLACED BOTH WATER SEPARATOR COALESCER BAGS. PRESSURIZATION AND AIR CONDITIONING SYSTEMS CHECKED NORMAL.