The US Federal Aviation Administration (FAA) said on Monday it is having oxygen masks in around 2,600 Boeing aircraft inspected due to issues with adhesive materials that could cause them to shift out of position.
The FAA said that the fault "could result in an inability to provide supplemental oxygen to passengers during a depressurization event."
The inspection order comes after multiple reports from passengers that the oxygen mask units had shifted out of position because of a "retention failure," according to the FAA.
The issue affects both older and newer versions of the Boeing 737 aircraft. The FAA said it is currently unable to estimate how many aircraft are affected by the defect and need reworking.
Boeing has been under increased pressure to improve quality controls since an incident earlier this year, when an almost new Boeing 737-9 MAX operated by Alaska Airlines lost a door plug during ascent, leading to a gaping hole in the fuselage.