As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT#620, SAN-BOS. 'STRONG MUSTY CHEMICAL ODOR OBSERVED BY BOTH PILOTS ON DESCENT PASSING THROUGH 18000 FT. PACK 1 SELECTED OFF PER FCOM 1 ODOR ISOLATION PROCEDURE. ODOR DISSIPATED AFTER FIVE MINUTES; REMOVED AND REPLACED OZONE FILTER FOR PACK 1 IAW AMM 21-51-41. OPS CHECK GOOD' NO LEAKS FOUND.'