The Federal Aviation Administration said on 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, which did not immediately comment, on June 17 issued a bulletin to airlines calling for visual inspections, the FAA said.

The FAA said its airworthiness directive was immediately effective and requires inspections and corrective actions if needed within 120 to 150 days based on the 737 model. The FAA is also barring airlines from installing potentially defective parts.

Airlines must conduct a general visual inspection and if needed replace oxygen generators with new or serviceable oxygen generators, strap thermal pads and reposition impacted oxygen generators, the agency said.

—David Shepardson, Reuters