The federal government's sluggish process for clearing workers to handle classified data is drawing new concern from government auditors, industry groups and at least one member of Congress, as an estimated 700,000 people wait for background checks to be completed.

The backlog has become so great that late last week, the Government Accountability Office took the highly unusual step of adding the effort to its list of "high-risk" programs, certifying that the process is in need of concerted action to prevent waste, fraud, abuse and mismanagement.

"A high-quality and timely personnel security clearance process is essential to minimize the risks of unauthorized disclosures of classified information and to help ensure that information about individuals with criminal histories or other questionable behavior is identified and assessed," U.S. Comptroller General Gene L. Dodaro said in a release.

In its report, the agency said the backlog of unfinished clearance investigations is more than 700,000 people, up from about 550,000 at the end of 2016. The Office of Personnel Management, the federal agency charged with doing the background checks, is still without a permanent director more than a year into President Trump's tenure. The GAO criticized OPM for failing to set long-term goals to address the backlog, saying "renewed and strong top leadership commitment" is needed to solve the problem.

Following the Government Accountability Office's action, Sen. Jon Tester (D-Mont.) released a statement criticizing the government's handling of clearance investigations.

"This is flat out unacceptable," Tester said in a statement. "These are the people responsible for protecting our nation's most sensitive information. If this process is compromised, our national security is compromised."

Processing background checks has long been a challenge for federal agencies, as investigators weigh the competing priorities of clearing workers quickly to perform critical work against blocking those who might do harm.

The issue flared up after 2013, when former National Security Agency contractor Edward Snowden leaked classified information despite being cleared. Later that year, a mass shooting by a cleared government employee in the Washington Navy Yard raised further questions about whether candidates were being vetted properly.

For the government contractors, the lengthy clearance process can delay important work and complicate hiring efforts. Some qualified workers must wait a year or more before investigators sign off.

"Companies have contracted, funded work they are trying to get done but they can't get started because they don't have the right people cleared," said David Berteau, president of the Professional Services Council, the government contractors' trade group.

The long wait times can be difficult for workers caught in the middle. The lucky ones will be paid while they wait on the sidelines, but others might have to wait.

One of those biding his time is Sagar Dubey, a 31-year-old Indian national who was tapped in 2016 to be a cargo specialist in the Army Reserve through a program meant to recruit skilled workers for the U.S. military. Until the process is complete, he cannot move forward in his desire to earn citizenship. A clearance would also allow Dubey, who works for a global technology consulting group that he declined to name, to work on federal contracts and advance within his company.

Dubey said some other skilled immigrants recruited through this program are much worse off.

"There are people who have had kids while they were waiting for their security checks to complete," Dubey said. "There are people who have ailing parents and they can't go home," out of concern that the travel would force them to start the review process anew.

Members of Congress have attempted to solve the problem by transferring oversight of clearances handled by the Defense Department — easily the largest source of clearance requests — away from OPM and to the Defense Security Service, a Pentagon subagency. The 2018 defense spending bill did just that, reversing an earlier reorganization that took the process out of the hands of the Defense Department and gave it to OPM.

An Aug. 22 implementation plan published by Federal News Radio suggests that the Defense Department wants to solve the problem in large part by switching to a system of "continuous evaluation," which involves using technology to constantly monitor the workforce for red flags rather than reevaluating people every five years, as is currently the case.

But industry groups say the agency has not spoken about its plans since August, raising questions about how the process is going.

"Until we have a clear path from [the Department of Defense] that we can read and comment on, we have questions about how well that transition will be executed and what will be its impact on investigations that are currently underway," Berteau said.

An earlier version of this story incorrectly described OPM as part of the General Services Administration. OPM is an independent federal agency. The story has been updated.