As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FUMES/DE- DECLARED EMERGENCY ON DECENT DUE TO OIL BURNING AND ELECTRICAL SMELL IN THE COCKPIT. CREW DONNED O2 MASKS. MAINTENANCE R&R RIGHT RECIRCULATING FAN AND FILTER PER B737 AMM 21-25. PERFORMED TAXI AND HIGH ENGINE RUNS, CYCLED PACKS NO FUTHER SMELLS NOTED.