The Federal Aviation Administration is investigating an incident aboard a Delta flight in which a cabin pressurization issue with the Boeing 737 caused some passengers to bleed from the nose and ears.

SALT LAKE CITY (AP) — The Federal Aviation Administration is investigating after a Delta Air Lines flight leaving Salt Lake City last weekend developed cabin pressure issues and left some passengers with bleeding eardrums, headaches and bloody noses.

Authorities are investigating a flight that turned around after the aircraft did not properly pressurize. Passengers bled from the ear and nose, local media said.