alaska airlines
An Alaska Airlines flight bound for Seattle from Chicago was diverted to Minneapolis-St. Paul International Airport (MSP) after the crew reported a cabin odor and breathing issues. This is an image of an Alaska Airlines plane at a gate at Dulles International Airport, Virginia, June 16, 2018. DANIEL SLIM/AFP/Getty Images

After passengers and crew members on an Alaska Airlines plane from Chicago to Seattle complained of breathing troubles, the flight was diverted to Minneapolis-St. Paul International Airport (MSP), Minnesota, Wednesday. The breathing troubles were caused by a “cabin odor.”

Officers at the MSP International Airport said they had medical crews responding to all the people who needed help. While the four crew members were taken to a local hospital, none of the passengers needed to be hospitalized.

The airline canceled the flight and was planning to rebook the passengers on another flight Thursday. Alaska Airlines Flight 51 took off from the O’Hare International Airport in Chicago at around 5:48 p.m. local time (6:48 p.m. EST) on Wednesday. It was diverted to MSP International Airport at around 7:17 p.m.

The plane had more than 140 passengers and six crew members. In a press release, the airline said it was investigating the cause of the odor and the plane was removed from service for an inspection.

“During the flight, the crew reported a cabin odor. As a precaution, the aircraft was diverted to Minneapolis-St. Paul International. Six crew members received a medical evaluation at the airport and four were transported to the hospital for further evaluation. Two passengers were also evaluated at the airport,” it said.

This is the second incident of an Alaska Airlines flight being diverted this week. On Tuesday, an Alaska Airlines flight from Seattle-Tacoma International Airport was forced to return to the airport when an odor was detected in the cabin. Three crew members were sent to a local hospital following this.

The flight landed at the Seattle-Tacoma Airport as a precaution and the port of Seattle fire department was also called. The fire crew members were unable to detect any odor. However, they still removed the aircraft from service.