As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FLIGHT CREW DECLARED AN EMERGENCY INTO LGA ON ACCOUNT OF ODOR IN THE CABIN AND COCKPIT. ODOR DISSIPATED AFTER PACK #1 WAS TURNED OFF. SMELLED LIKE GUN POWDER. MAINTENANCE ACCOMPLISHED JOB CARD 43L00021001- SMOKE ODOR FUMES. FOUND PACK 1 ACM TO GRIND AND EMIT "GUN POWDER " ODOR . REPLACED PACK 1 ACM IAW AMM 21-51-05. OPS CHECK NORMAL.