The Federal Aviation Administration (FAA) said Thursday that it launched an investigation into Boeing to determine if the company failed to ensure that its products were safe for operation. 

"FAA formally notified Boeing that it is conducting an investigation to determine if Boeing failed to ensure completed products conformed to its approved design and were in a condition for safe operation in compliance with FAA regulations," the agency said in a statement. 

The investigation stems from an incident last Friday when a Boeing Model 737 Max 9 lost a door plug mid-flight and had to make an emergency landing, according to the FAA. 

The FAA has already grounded every Boeing 737-9 Max with a plug door.

This is a developing story. Check back for updates.