George Mason University will build a $40 million high-security laboratory in Prince William County to test and develop new vaccines and treatments to defend the public against bioterrorism, officials announced yesterday.

University officials will seek $25 million from the National Institute of Allergy and Infectious Diseases to help pay for the facility. GMU has committed to paying the balance but hopes that it can recover the funds through other private and public grants, officials said. Groundbreaking could begin as soon as 2006, but timing will depend on funding.

The 70,000-square-foot lab will be part of GMU's National Center for Biodefense, a graduate program designed to train a new generation of experts to defend society from the estimated 80 pathogens emerging and in existence worldwide. Inside, graduate students and scientists will study airborne biological pathogens and how to fight them. They will also evaluate how new vaccines and therapeutic drugs can protect against such pathogens as anthrax, tularemia and the plague, said Charles L. Bailey, the center's executive director and a former commander of the U.S. Army Medical Research Institute of Infectious Diseases at Fort Detrick.

"We feel that [this facility is] very important," he said. "It could be available to support federal agencies in the event of an emergency. . . . We like the fact that we're relatively close to the military's premier laboratory [Fort Detrick] . . . and we can take advantage of some of their staff for our teaching and research."

Sean T. Connaughton (R), chairman of the Prince William Board of County Supervisors, touted the plan yesterday as a step toward establishing Prince William as an international center for biodefense research.

"Step by step, we're seeing the pieces of the puzzle fall together for Prince William," he said. The lab "really is going to make a dramatic impact, not just on our community, but on the nation and world. They need this facility no matter what."

The lab is the latest in a string of economic development projects to come to this part of the county, just west of the city of Manassas. The American Type Culture Collection, a nonprofit repository for cell lines, microorganisms and other biological materials, including many dangerous bacteria and viruses, makes its home in Prince William. Pharmaceutical giant Eli Lilly and Mediatech Inc., a biotech company now in Herndon, both plan to locate plants in the county's Innovation industrial park, which includes GMU's Prince William campus, just west of the Manassas city line.

Unlike Fort Detrick, which researches, develops and tests vaccines and therapeutic drugs for the military, the focus of this lab will be to protect the public, Bailey said. Because such dangerous pathogens can't be tested on people, the only way the Food and Drug Administration can gather data on their effects is to use animals whose reactions are similar to that of humans, Bailey said. Mice and monkeys, among other animals, could be used, he said.

The lab will operate under strict FDA guidelines, which govern everything from record-keeping to the types of equipment used, Bailey said. Strict security measures -- similar to those at Fort Detrick -- will be in effect, he said. A mound of dirt and fencing will surround the facility. Background checks and extensive training will be required for anyone who has access to the germs under study. Also, researchers will work inside gas-tight glove boxes inside rooms with several air filtration systems, inside other rooms, he said.

The quantities tested will be so small that even if pathogens do escape, it's highly unlikely that they could pose a threat, he said.

University officials are discussing whether to build the lab on the Prince William campus or just beyond it, said Lawrence D. Czarda, vice president of the campus.