As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) PASSING THRU 4,000 FT ON DESCENT THE PILOTS NOTICED A "BLEACHY-BURN" ODOR. THEY CHECKED WITH THE F/A`S IN THE BACK OF THE ACFT AND THE ODOR WAS ALSO NOTICED IN THE PASSENGER CABIN. THE PILOTS DECIDED TO PUT ON THEIR OXYGEN MASKS AND DECLARED A PAN PAN. THE ACFT LANDED WITHOUT FURTHER INCIDENT RESOLUTION: MOC REQUEST, ENGINE RUNS CARRIED OUT, UNABLE TO DUPLICATE.