As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 1885 PHL-FLL - CABIN ODOR - FLIGHT RETURNED TO PHL DUE TO A STRONG, VILE ODOR IN THE CABIN. FUMES WERE OF UNKNOWN ORIGIN AND CAUSED ONE PASSENGER TO BECOME ILL. MAINTENANCE FOUND OIL CONTAMINATION IN APU - DECONTAMINATED ENVIRONMENTAL CONTROL SYSTEM.