As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 725, SNN-PHL: AFTER TAKEOFF, FLIGHT ATTENDANTS REPORTED INSULATION LIKE MATERIAL COMING FROM OVERHEAD VENTS. FLIGHT RETURNED TO SNN. MAINTENANCE FOUND THAT THE LEFT RECIRC FILTER HAD BROKEN DOWN, ALLOWING MATERIAL FROM FILTER INTO THE DUCT SYSTEM. THE FILTER WAS REPLACED AND THE DUCT SYSTEM CLEARED OF EXCESS DEBRIS.