Narrative:

At FL330, a flight attendant requested that we cool off the cabin. The mixing valve would not move in automatic or manual. About 1 min later, I noticed the duct pressure on the right side was near zero while the left side was normal. Next, the cabin altitude started to rise and the flow light was on. We asked for a lower altitude (FL210) and they assigned FL270 and said to expect lower. Then the cabin rate of climb began to increase and cabin altitude passed 10000 ft and became uncontrollable. At this point we declared an emergency and requested lower. We ram the rapid decompression checklist. While descending, the cabin altitude passed 14000 ft and the masks dropped. 2 flight attendants reported smoke/fumes in the cabin (probably the smell of the oxygen generators). We diverted to bdl and made an uneventful landing. No aircraft damage, no injuries. Supplemental information from acn 566076: as we descended, cabin altitude reached 10000 ft. We declared emergency, ran rapid decompression checklist. Center gave us 11000 ft. In descent, cabin altitude reached 14000 ft, deploying passenger oxygen masks. We eventually descended to 9000 ft. Once at 9000 ft MSL with cabin altitude verified below 10000 ft, we told flight attendants to approve removal of oxygen masks, followed by uneventful landing at bdl.

Related reports:

Google
 

Original NASA ASRS Text

Title: AN MD80 CREW, IN CRUISE AT FL330, WERE UNABLE TO CTL THE CABIN PRESSURE, SPAWNING AN EMER REQUEST FOR A LOWER ALT.

Narrative: AT FL330, A FLT ATTENDANT REQUESTED THAT WE COOL OFF THE CABIN. THE MIXING VALVE WOULD NOT MOVE IN AUTO OR MANUAL. ABOUT 1 MIN LATER, I NOTICED THE DUCT PRESSURE ON THE R SIDE WAS NEAR ZERO WHILE THE L SIDE WAS NORMAL. NEXT, THE CABIN ALT STARTED TO RISE AND THE FLOW LIGHT WAS ON. WE ASKED FOR A LOWER ALT (FL210) AND THEY ASSIGNED FL270 AND SAID TO EXPECT LOWER. THEN THE CABIN RATE OF CLB BEGAN TO INCREASE AND CABIN ALT PASSED 10000 FT AND BECAME UNCTLABLE. AT THIS POINT WE DECLARED AN EMER AND REQUESTED LOWER. WE RAM THE RAPID DECOMPRESSION CHKLIST. WHILE DSNDING, THE CABIN ALT PASSED 14000 FT AND THE MASKS DROPPED. 2 FLT ATTENDANTS RPTED SMOKE/FUMES IN THE CABIN (PROBABLY THE SMELL OF THE OXYGEN GENERATORS). WE DIVERTED TO BDL AND MADE AN UNEVENTFUL LNDG. NO ACFT DAMAGE, NO INJURIES. SUPPLEMENTAL INFO FROM ACN 566076: AS WE DSNDED, CABIN ALT REACHED 10000 FT. WE DECLARED EMER, RAN RAPID DECOMPRESSION CHKLIST. CTR GAVE US 11000 FT. IN DSCNT, CABIN ALT REACHED 14000 FT, DEPLOYING PAX OXYGEN MASKS. WE EVENTUALLY DSNDED TO 9000 FT. ONCE AT 9000 FT MSL WITH CABIN ALT VERIFIED BELOW 10000 FT, WE TOLD FLT ATTENDANTS TO APPROVE REMOVAL OF OXYGEN MASKS, FOLLOWED BY UNEVENTFUL LNDG AT BDL.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.