An Alaska Airlines flight headed for Phoenix on Wednesday was forced to return to Portland International Airport in Oregon shortly after take off after passengers and crew detected fumes in the cabin. An Alaska Airlines spokesperson said flight 646 declared an emergency and started the return when the odor was detected and landed safely back at the airport. Once they landed, Port of Portland told USA TODAY the Port fire department responded to the reports of fumes in the cabin. Fire and rescue crews investigated, but could not determine what caused the smell. "The issue is now in the hands of Alaska maintenance," said Allison Ferre, Port of Portland's media relations manager. The airline confirmed that its maintenance crew is currently inspecting the aircraft. According to Ferre, after passengers deplaned the first aircraft, seven passengers and crew members asked to be seen by a medical professional, but no one was taken to the hospital. The reasons for the requests were not specified by the airline or Port of Portland.<br/>