WASHINGTON — A dozen states are competing for a government research lab full of killer germs like anthrax, avian flu and foot-and-mouth disease — a prospect some of their residents want to avoid like the plague.

The states are bidding for a proposed 520,000-square-foot National Bio- and Agro-Defense Facility that will cost at least $450 million to build. It would replace an aging, smaller lab at Plum Island, N.Y., where security lapses after the 2001 terrorist attacks drew scrutiny from Congress and government investigators.

The Homeland Security Department facility promises at least 300 lab-related jobs, and more in construction. Congress provided money for the $47 million design and architecture, but no money has been appropriated yet for construction or operations.

The written of each state bid have not been made public. However, they were required to make available at least 30 acres of land.

The competition intensified last month as federal officials began visits to 17 potential sites. The government has said it would take into account offers of roads, cheap water supplies, and discounted utilities, and states are dangling their premier scientific expertise and community treasures as bait.

“Protecting human life and our livestock and food supply is important to society and we want to be a part of that,” a university researcher in San Antonio who is leading the city’s effort, Harold Timboe, said. San Antonio is offering three sites. Officials visited one of the sites yesterday and are scheduled to visit a second later in the day and the third tomorrow.

Besides Texas, which has a total of four sites in contention, states bidding for the site are California, Georgia, Kansas, Oklahoma, Maryland, Mississippi, Missouri, North Carolina, and Wisconsin. Georgia, Kansas, and Mississippi are offering two sites each, while Kentucky and Tennessee are working together for one site in Kentucky.

DHS officials will visit the fourth site in Texas on Wednesday and finish the week in Missouri. A stop in North Carolina will finish the visits.

In June, officials will narrow down their options to three to five sites. The winner should be announced in October 2008, with the lab operating by 2014.

Pockets of opposition have emerged in some states.

The Dunn, Wis., Town Board, the Dane, Wis., County Board of Supervisors, and the Tracy, Calif., City Council voted to oppose the sites proposed for their communities.

The Wisconsin bid has drawn the ire of patent lawyer George Corrigan, who is concerned about pathogens finding their way into the community near a Lake Kegonsa home he owns. The rural area just outside Madison includes many landowners who have bought development rights to preserve the land, and much of the opposition stems from the development the lab would bring.

“They made sweeping statements of ‘Trust us,’ generalizations that nothing bad will happen. That may be good enough for some people, but not for me,” Mr. Corrigan said.

At a public meeting, neighbors of the potential Leavenworth, Kan., site voiced concerns about lab safety, the lab’s effect on property, congestion, and the project’s potential to make the area a terrorism risk.