Boeing and the National Transportation Safety Board argued Wednesday over whether the company has cooperated with investigators looking into the blowout of a door-plug panel on one of its planes during a flight in January.

The safety board’s chair, Jennifer Homendy, told a Senate Committee that for two months Boeing repeatedly refused to identify employees who work on door panels on Boeing 737s. Investigators want to interview them.

Homendy also said the company has failed to provide documentation about a repair job that included removing and reinstalling the panel on the Alaska Airlines Boeing 737 Max 9 that suffered the blowout — or even whether Boeing kept records.

“It’s absurd that two months later we don’t have that,” Homendy said. “Without that information, that raises concerns about quality assurance, quality management, safety management systems” at Boeing.

Shortly after the Senate hearing ended, Boeing responded that it gave the NTSB the names of all employees who work on 737 doors — and had previously shared some of them with investigators.

“Early in the investigation, we provided the NTSB with names of Boeing employees, including door specialists, who we believed would have relevant information,” a company spokesman said in a statement. “We have now provided the full list of individuals on the 737 door team, in response to a recent request.”

NTSB fired back, saying that Homendy “stands behind her accurate testimony” to the Senate Commerce Committee.

It is still not clear whether Boeing kept records about who removed the plug — a panel that takes the place of extra emergency doors when those doors are not required — on the Alaska plane last September.

“If the door plug removal was undocumented there would be no documentation to share,” Boeing said.

Boeing has been under increasing scrutiny since the Jan. 5 incident in which a panel that plugged a space left for an extra emergency door blew off an Alaska Airlines Max 9. Pilots were able to land safely, and there were no injuries.

In a preliminary report last month, the NTSB said four bolts that help keep the door plug in place were missing after the panel was removed so workers could repair nearby damaged rivets last September. The rivet repairs were done by contractors working for Boeing supplier Spirit AeroSystems, but the NTSB still does not know who removed and replaced the door panel, Homendy said Wednesday.

Homendy said Boeing has a 25-member team led by a manager, but Boeing has declined repeated requests for their names. The manager of the team is on medical leave and unavailable, and security-camera footage that might have shown who removed the panel was erased and recorded over 30 days later, she said.

Lawmakers seemed stunned.

“That is utterly unacceptable,” said Sen. Ted Cruz, R-Texas.

Sen. Edward Markey, D-Mass., accused Boeing of failing to emphasize safety, which “endangered the lives of the 180 passengers and crew aboard the Alaska Airlines flight.”

Sen. Maria Cantwell, D-Wash., who represents the state where Max jetliners are assembled, said she would press Boeing to cooperate with NTSB. She also noted that Boeing is a leading U.S. exporter and major defense contractor.

“We need to get this right,” Cantwell said. “We need to help with the investigation so we can find out what in our system needs to be improved.”

The Federal Aviation Administration recently gave Boeing 90 days to say how it will respond to quality-control issues raised by the agency and a panel of industry and government experts. The panel found problems in Boeing’s safety culture despite improvements made after two Max 8 jets crashed in 2018 and 2019, killing 346 people.