The Federal Aviation Administration on Friday said it will audit Boeing‘s production line, a week after a door plug blew off an Alaska Airlines 737 Max 9.

The agency said it is considering using “an independent third party” to oversee Boeing inspections and quality of its manufacturing.

The FAA grounded more than 170 Boeing 737 Max 9s, most of the world’s fleet, after that accident. The agency said the audit applies to Boeing’s production line for that plane model and its suppliers “to evaluate Boeing’s compliance with its approved quality procedures.

“The results of the FAA’s audit analysis will determine whether additional audits are necessary,” said the agency.

The FAA said it will also evaluate risks around Boeing’s ability to self-monitor quality control and other aspects of airplane production. The agency on Thursday announced an investigation into whether the manufacturer failed to ensure its planes were airworthy and conformed to their design.

“The grounding of the 737-9 and the multiple production-related issues identified in recent years require us to look at every option to reduce risk,” FAA Administrator Mike Whitaker said in a statement.

Earlier this week, Boeing’s CEO Dave Calhoun told staff that the company acknowledges its “mistake” and said it would move past the incident, the latest defect and the most serious in recent years from Boeing.

No serious injuries were reported on the Alaska flight, and no one was seated next to the panel that blew out nor in the next seat over.

Still, the incident ramps up scrutiny on Boeing’s quality problems and on regulators that oversee the industry.

“The FAA conducts final safety checks and issues airworthiness certificates for newly produced Boeing 737s,” the agency said.