The Federal Aviation Administration (FAA) is investigating a Delta Air Lines flight after pressurization issues caused some passengers to say they suffered ruptured eardrums and nosebleeds and forced the plane to turn around.

On Sunday, the flight, a Boeing 737-900, was traveling from Salt Lake City, Utah, to Portland, Oregon, when it was forced to make an emergency landing back in Salt Lake City due to pressurization issues.

Speaking to KSLTV, one passenger, Caryn Allen, said she looked over and noticed her husband was leaning forward in his seat and had both of his hands over his ears. Allen then noticed other passengers in pain too, saying: “I looked about a row behind me over on the other side of the aisle and there was a gentleman that clearly had a very bad bloody nose and people were trying to help him.”