Narrative:

Purser advised of unusual fumes in cabin. I investigated and concurred that there were unusual; and strong fumes that resembled burning plastic. We accomplished the 'smoke; fire; fumes' checklist. Since the condition continued; we followed the checklist's [direction] to land at the nearest suitable airport. We declared an emergency and diverted to ZZZZ for smoke and fumes in the cabin. Unusual event that was caused by a fan motor overheat.

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Original NASA ASRS Text

Title: B777 flight crew is informed of fumes in the cabin and the Captain; who was initially on break; investigates. After running the smoke and fumes checklist the crew elects to divert to the nearest suitable airport.

Narrative: Purser advised of unusual fumes in cabin. I investigated and concurred that there were unusual; and strong fumes that resembled burning plastic. We accomplished the 'Smoke; Fire; Fumes' checklist. Since the condition continued; we followed the checklist's [direction] to land at the nearest suitable airport. We declared an emergency and diverted to ZZZZ for smoke and fumes in the cabin. Unusual event that was caused by a fan motor overheat.

Data retrieved from NASA's ASRS site as of July 2013 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.