The Federal Aviation Administration said Monday it is requiring inspections of 2,600 Boeing 737 airplanes because passenger oxygen masks could fail during an emergency.

The FAA said it was requiring the inspections of 737 MAX and NG airplanes after multiple reports of passenger service unit oxygen generators shifting out of position, an issue that could result in an inability to provide supplemental oxygen to passengers during a depressurization event.

Boeing on June 17 issued a bulletin to airlines calling for visual inspections.