Senators on Tuesday attacked the CEO ofBoeingfor the planemaker’s tarnished safety record, overshadowing his apology to families who lost loved ones in two 737 MAX crashes and acceptance of responsibility after a January mid-air emergency.

Chief Executive Dave Calhoun retained his composure under repeated questioning about how much he is paid,Boeing’s safety culture, and why he is not immediately resigning instead of retiring by year’s end, at a hearing before the Senate Permanent Subcommittee on Investigations.

He faced harsh questioning from Republican Senator Josh Hawley who asked, “why haven’t you resigned?” and accused Calhoun of “strip-mining” the company while earning a handsome multimillion-dollar pay package.

The hearing marked the first time Calhoun has faced lawmakers’ questions and put the spotlight on Boeing’s souring safety reputation and the departing CEO following a management shakeup.

Boeing stock was down nearly 2% at $175.03 late on Tuesday.

Calhoun acknowledged the Alaska Airlinesdoor plug incident on Jan. 5 was the result of a manufacturing defect.Boeingalso took responsibility for the development of a key software system linked to the 2018 and 2019 fatal crashes in Indonesia and Ethiopia which killed a combined 346 people.

“I am here to answer the questions. I am here in the spirit of transparency and I am here to take responsibility,” Calhoun told reporters earlier as he walked into the hearing room.

Senator Richard Blumenthal who chairs the subcommittee told the hearing there is overwhelming evidence that the Justice Department should pursue prosecution againstBoeing.

Prosecutors found in May that Boeing had failed to “design, implement, and enforce a compliance and ethics program” as part of complying with a deferred prosecution agreement following the fatal crashes. Prosecutors have until July 7 to inform a federal judge in Texas of their plans.

Last week,Boeingtold the US Justice Departmentit did not violate a deferred prosecution agreement. The DPA had shielded the company from a criminal charge arising from the crashes in 2018 and 2019 that killed 346 people.

Blumenthal said a new whistleblower has come forward after a hearing with a previous whistleblowerin April.Blumenthal said on Tuesday that Sam Mohawk, a currentBoeingquality assurance investigator at its 737 factory in Renton, Washington, recently told the panel he had witnessed systemic disregard for documentation and accountability of nonconforming parts.

In a report released by the committee ahead of the hearing, Mohawk said his work handling nonconforming parts became significantly more “complex and demanding” following the resumption of MAX production in 2020 following two fatal crashes involving the model.

The report said Mohawk filed a related claim in June with the Occupational Safety and Health Administration.

Boeing said in a statement that the planemaker is reviewing the claims it heard about on Monday. “We continuously encourage employees to report all concerns as our priority is to ensure the safety of our airplanes and the flying public, it said.

Boeing also said it has increased the size of its quality team and “increased the number of inspections per airplane significantly since 2019.”

Blumenthal called the hearing a “moment of reckoning” for Boeing.

“Boeing needs to stop thinking about the next earnings call and start thinking about the next generation,” Blumenthal said.

Since the Jan. 5 mid-air blowout of a door plug on a 737 MAX 9 jet, scrutiny of the planemaker by regulators and airlines has intensified.

The National Transportation Safety Board said four key bolts were missing from the Alaska Airlines plane. The Justice Department has opened a criminal investigation into the incident.

On May 30,Boeingdelivered a quality improvement planto the FAA after Whitakergave the company 90 daysto develop a comprehensive effort to address “systemic quality-control issues.” He has barred the company from expanding production of the MAX.