Congressional pressure for the firing of Office of Personnel Management Director Katherine Archuleta is growing, with 18 Republican House members sending President Obama a letter requesting her ouster.

The letter follows four hearings, including three last week, where Archuleta was grilled by House and Senate members over the cyber theft of personal information belonging to at least 4.2 million current and former federal employees.

[OPM director survives congressional inquisition, for now]

Katherine Archuleta, director, Office of Personnel Management, gestures while she testifies before the Senate Appropriations subcommittee on Financial Services and General Government hearings to review IT spending and date security at the Office of Personnel Management in Washington, Tuesday, June 23, 2015. (AP Photo/Cliff Owen)

The effort was organized by Rep. Jason Chaffetz (Utah), chairman of the House Oversight and Government Reform Committee. The letter says, “Director Archuleta and her leadership team failed to correct serious vulnerabilities to OPM’s network and cybersecurity posture despite repeated and urgent warnings from OPM’s Inpector General that date back to 2007, at least.”

Archuleta has been in office about 19 months.

Noting an inspector general’s report that found 11 major OPM information systems lacked security authorization, the members complained that five of those systems were in the office of Donna Seymour, OPM’s chief information officer, whose dismissal also was requested.

“Ms. Seymour acknowledged in the hearing the risks inherent in operating systems without valid authorizations yet continued to defend her decision to ignore the Inspector General and operate important systems without authorizations in place,” the letter said. “That decision alone is, in our opinion, disqualifying.”

OPM responded with a statement from spokesman Samuel Schumach: “Through Director Archuleta’s leadership, and the expertise of Donna Seymour, OPM has embarked on an aggressive modernization and security overhaul of our network and its systems — the very upgrades that made it possible for OPM to identify the recent cyberattacks. Director Archuleta is committed to finishing the important work outlined in her IT strategic plan and working with our inter-agency partners.”

Last week, White House Press Secretary Josh Earnest came to her defense, saying, “the administration and the President continue to believe that she’s the right person for the job.”

Tony Scott, the administration’s chief information officer, also spoke up for Archuleta at a hearing. Improvements in OPM’s cyber program under Archuleta’s leadership, Scott said, have made a “dramatic difference.

One Democrat, Rep. Rep. Ted Lieu (D-Calif.) has called for the removal of the OPM officials. In the Senate, Sen. Ron Johnson (R-Wis.) also expressed no confidence in Archuleta.

[Feds anger grows over data breach, amid fears that the number affected could rise]