As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FUME EVENT DURING DECENT STARTING AT 12000' UNABLE TO IDENTIFY SOURCE SMELL RESEMBLES WET MUSTY SMELL-R&R RECIRCULATION FILTERS IAW AMM 21-21-41. ALSO PERFORMED LEVEL "A" DECONTAMINATION OF THE ECS IAW AMM 21-00-00. NO FUMES OR SMELL NOTED. OK FOR SVC.