As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RETURNED TO SLC DUE TO PUNGENT SEWER ODOR THROUGHOUT THE CABIN. DECLARED EMERGENCY. TROUBLESHOT PER MSI WORKCARDS FOUND ODOR FROM NBR 1 ENGINE. LOCKED OUT LEFT ENGINE BLEED PER MEL AND ISSUED MON LP TO PERFORM COMPRESSOR WASH WITHIN 5 DAYS AND BOROSCOPE WITHIN 10 DAYS. (LP# 7728336)