U.S. Secretary of State Hillary Clinton checks her PDA upon departure in a military C-17 plane from Malta bound for Tripoli, on October 18, 2011.National Journal

Big federal document dumps, especially the kind that involve presidential frontrunners, don't come cheap or easily.

On June 30, acting under a court order, the State Department will begin sharing the results of what could be a $1 million-plus project: The online release of portions of 55,000 pages of Hillary Clinton's email messages from her time as secretary of State.

The messages, such as a small subset related to Libya and the Benghazi attacks released last month, will draw ravenous attention from the press and GOP opposition researchers.

The release will be the fruit of what court documents and State officials reveal to be a complex process that's requiring a major effort by the agency's Freedom of Information Act staff and drawing in personnel from other parts of the agency.

While it's impossible to assign a specific total cost to an ongoing review, it could surpass $1 million worth of staff time if it extends through January, State's court-imposed deadline to complete the process.

According to a State spokesman and a May court filing, the department has devoted a dozen full-time staff to the case within its FOIA office: a project manager, two case analysts and nine FOIA reviewers. But the review also requires participation from staff outside of that office.

Nate Jones, director of the Freedom of Information Act Project at the National Security Archive, said the time-consuming review is not without consequences. He cites State's acknowledgement that the review is consuming a major chunk of its FOIA resources, delaying other reviews—including his own group's push for more records on Henry Kissinger.

The agency has not provided an estimated cost for the review, which will have consumed more than six months if State works through January.

Clinton turned over physical copies of the messages printed from her private server in December, but the review didn't begin in earnest until months later.

A five-week scanning process was completed in May, and State estimated in mid-May that they would finish uploading the messages into a database in mid-June, according to a court filing.

The department provided National Journal with the rough salary ranges under the governmentwide "general schedule," or GS pay scale, of the 12 personnel working full-time on the review.

Their possible salaries range from a low of roughly $63,700 to a high of over $150,000. "We have the option to add or hire additional staff if necessary," the spokesman said.

So if just those dozen staffers worked on the project for seven months, the cost of that manpower alone would range from at least $445,000 to more than $1 million.

But the labor-intensive review goes well beyond those 12 staff members.

A court filing last month from a State official—part of a FOIA lawsuit from a Vice News reporter that led to the release schedule—provided a look at the inner workings of the State review, which began with an intensive scanning process.

It notes that in addition to the full-time FOIA division staff, there are "other analysts and information technology specialists who provide collateral assistance to this review in addition to their regular duties."

The document is a declaration from John Hackett, State's acting director of the Office of Information Programs and Services, who had proposed releasing all the messages early next year, but a federal judge shot down that plan and instead wants batches released every 30 days.

There's also as-needed vetting of documents by "subject matter experts," and reviews by State's Office of the Legal Adviser.

The review extends outside of State too, requiring review by other agencies in some cases, the court filing states.

The document notes that State has advised the Central Intelligence Agency, Department of Defense, Department of Justice, Office of the Director of National Intelligence, National Security Council, and the White House of the review and asked for their assistance.

The staff time devoted to the review of messages from Clinton's exclusive use of a private email server and account has drawn GOP criticism. In March, GOP Rep. Mike Pompeo told Bloomberg that "this challenge was created when a government employee decided not to use the government system."

But State officials have pushed back against such criticism, arguing that it would need to carefully vet the messages regardless of whether Clinton used a private system or the government's.

"The cost and work of reviewing Secretary Clinton's emails for release would've been roughly the same regardless of whether she had a state.gov email or a personal email and regardless of where her email was housed," said Jen Psaki, then a State Department spokeswoman, in March comments.

Psaki, now White House communications director, rejected the notion that the review would cost "millions and millions" of dollars, calling that "far outstated."

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.