As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - FLT 3495 - AFTER TAKEOFF, CREW RETURNED TO DFW BECAUSE OF STRONG ODOR STILL PRESENT AFTER BLEEDS SELECTED OFF. PASSENGER AND CREW COMPLAINED OF HEADACHES. MAINTENANCE PERFORMED GROUND ENGINE RUNS AND FOUND NO DEFECTS. SUSPECT RECIRCULATION FAN THAT IS ON MEL TO BE THE SOURCE OF THE SMELL. (M)