Washington — The Homeland Security Department has swept aside evaluations of government experts and named Mississippi — home to powerful U.S. lawmakers with sway over the agency — as a top location for a new $451 million, national laboratory to study some of the most virulent biological threats, according to internal documents.

The Mississippi site, which received an evaluation score of 81, was ranked ahead of several higher-scoring sites on the list of five finalists, including one in Athens that was scored 90. Another Athens site, also scored 90, remains on the list of five finalists.

Georgia officials contacted this weekend had not yet gotten the word Athens' position in the competition for the lab was in jeopardy. "The results of the [evaluation] process from each of the sites show just how strong our bid is," said Bert Brantley, spokesman for Gov. Sonny Perdue. "Our hope is that this decision will be based on the best location for the project, not any other criteria."

Mississippi's lawmakers include the Democratic chairman of the department's oversight committee in the House and the senior Republican on the Senate Appropriations Committee, which is expected to approve money to build the National Bio and Agro-Defense Facility at one of five sites being considered. The two lawmakers said they were unaware of the Homeland Security evaluation system that scored the Mississippi site so low.

The disclosure is the latest example of what critics assert is the Bush administration's politicizing of government decisions, such as efforts to steer science over global warming at the Environmental Protection Agency and hiring and firing practices at the Justice Department.

"It is very suspicious," said Irwin Goldman of the University of Wisconsin, a leader of the unsuccessful effort to build the lab in Madison. His community's offer was among nine sites rejected even though the government scored it more highly than Mississippi's. "We wondered how everybody else did. It's interesting to know that we came out ahead of one that was short-listed."

Besides Georgia, states where locations were eliminated despite earning scores higher than Mississippi included California, Maryland, Texas and Wisconsin.

Government experts originally expressed concerns that the proposed site in Flora, Miss., was far from existing biodefense research programs and lacked ready access to workers already familiar with highly contagious animal and human diseases. They assigned the site a score that ranked it 14th among 17 candidate sites in the United States.

But a senior Homeland Security official, Undersecretary Jay Cohen, overruled those concerns under the theory that skilled researchers would move to Mississippi if it were selected for the new lab, according to a July 2007 internal government memorandum, marked "sensitive information" and obtained by the AP.

A former Navy officer, Cohen is a political appointee, nominated by President Bush in June 2006.

Tom Jackson, spokesman for the University of Georgia, said UGA officials also knew nothing of Mississippi possibly supplanting Athens. "It's clear that a key strength of the Athens site is its proximity to existing research expertise in this field at both the University of Georgia and other facilities in Athens and being just 60 miles from the Centers for Disease Control," he said.

U.S. Sen. Saxby Chambliss (R-Ga.) said through a spokeswoman he was "still committed to work hard to get that in Athens. He still believes Athens is the No. 1 site. With the CDC in Atlanta, he thinks it's the stronger site."

Under the department's own rules, it was free to disregard the recommendations of the government experts it appointed. But it said it selected advisers who were experts and were screened carefully for any conflicts of interest, working through seven stages of recommendations over 18 months. Cohen personally made the choices for the five sites in the eighth and final stage of the decision.

Mississippi's lawmakers include Democratic Rep. Bennie Thompson, chairman of the House Homeland Security Committee, and Sen. Thad Cochran, the top Republican on the Senate Appropriations Committee and the subcommittee that oversees Homeland Security money. Each said he was not aware of the department's deliberations.

A spokeswoman for Cochran, Margaret McPhillips, denied that the department relied on the scoring system described in the documents obtained by the AP. She dismissed it as rumor.

"Our congressional delegation doesn't know about a scoring system," McPhillips wrote in an e-mail to the AP. "Mississippi's governor does not know of one. DHS is in Mississippi right now for a site visit and just confirmed with us that there is no scoring system.

"Mississippi has put forth a compelling application and it does not surprise me that someone might be trying to diminish the strength of our proposal by spreading this rumor," McPhillips wrote.

Rep. John Dingell (D-Mich.), chairman of the House Energy and Commerce Committee, held oversight hearings in May examining the risks of building the new lab on the U.S. mainland near livestock herds. The facility would replace an existing 24-acre research complex on isolated Plum Island, about 100 miles northeast of New York City in the Long Island Sound. Besides foot-and-mouth disease, researchers also would study African swine fever, Japanese encephalitis, Rift Valley fever and the Hendra and Nipah viruses. Construction would begin in 2010 and take four years.

In his memo, Cohen acknowledged the government evaluation committees graded Mississippi's site as merely "satisfactory" with scores of 72 and 75 in its research and work force categories, respectively. The Mississippi site's overall grade was 81, or "very good," which still was lower than nine other rejected U.S. sites.

"While I take the committees' concerns to heart, I do not concur with the low scores," Cohen wrote.

A department spokeswoman, Amy Kudwa, said the agency's internal committee reviews "did not appropriately consider the unique contributions certain consortia committed to make in their proposals."

AJC staff reporter Rhonda Cook and Associated Press writer Eileen Sullivan contributed to this article.