As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STRONG PETRO/CHEMICAL ODOR IN A/C BLEED, CLOSED NR 2 PACK AND NR 2 ENG ISOLATION VALVE, ODOR DIMINISHED. EXTENSIVE INSPECTION AND OPERATIONAL CHECKS COULD NOT DETERMINE SOURCE OF ODOR. DUE TO HISTORY OF ODOR IN CABIN, REPLACED WATER SEPARATOR BAGS AND PERFORMED DUCT BURNOUT.