As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ACFT BEGAN TO LOSE PRESSURIZATION. BEGAN DESCENT THROUGH 14,000, DEPLOYED CABIN OXYGEN MASKS. CABIN ALTITUDE REACHED 8,500. C/W QRH EMERGENCY PROCEDURE 3-2. CONTINUED DESCENT. LANDING WAS UNEVENTFUL. AIRCRAFT RETURNED TO ATL AFTER T/O. EMERGENCY DECLARED. AIR CONDITIONING PACK - LEFT SIDE.