As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: LH PACK FAILED WITH RH PACK ALREADY ON MEL, OXYGEN MASKS DEPLOYED AND CREW DESCENDED BELOW 10,000 FT; FLIGHT DECLARED EMERGENCY AND RETURNED TO FIELD. ACCOMPLISHED FUNCTIONAL TEST OF LH PACK IAW AMM 21-00-05, OPS CHECK GOOD.