Narrative:

On climb out, smoke in cabin and cockpit. Declared emergency. Returned to atl. Odor was the smell of burning plastic. Flight attendants and passenger also smelled smoke. Smoky haze remained in forward lavatory area after landing.

Google
 

Original NASA ASRS Text

Title: A B737-800 ON CLBOUT AT 2500 FT DECLARED AN EMER AND DIVERTED DUE TO SMOKE IN CABIN AND COCKPIT CAUSE UNKNOWN.

Narrative: ON CLBOUT, SMOKE IN CABIN AND COCKPIT. DECLARED EMER. RETURNED TO ATL. ODOR WAS THE SMELL OF BURNING PLASTIC. FLT ATTENDANTS AND PAX ALSO SMELLED SMOKE. SMOKY HAZE REMAINED IN FORWARD LAVATORY AREA AFTER LNDG.

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.