HELENA -- Federal regulators gave the final go-ahead Thursday to a biological research lab slated for Hamilton designed to study the most dangerous pathogens known.

Officials at the National Institutes of Health, which oversees Rocky Mountain Laboratories in Hamilton, announced they have formally decided to build a Biosafety level four research lab at the Hamilton campus. The new lab, which could break ground by late this summer, will be among a handful in the nation designed to study deadly diseases for which there is no cure, like Ebola.

The proposal, which was studied and debated for years, has drawn praise from many, including Gov. Judy Martz, and criticism from some locals who say the lab could leak deadly microbes or make Hamilton a target for terrorists.

NIH appeared to dismiss those concerns in its decision.

''The risk assessment indicated that there is essentially no risk to the community from release of infectious agents," the document read. It later went on to say that heightened surveillance and security ''will be in place to prevent unauthorized use or removal of biological material."

''I think this is the right thing to do," said Marshall Bloom, associate lab director at Rocky Mountain Labs. ''I think it's the right time to do it and the right place to do it at."

In its justification for putting the lab in Hamilton, federal officials cited the lab's long history of studying infectious disease, starting with Rocky Mountain spotted fever almost a century ago.

Bloom said the lab has always been prestigious and the addition of the new facility will only add to its status. He also acknowledged the people who have opposed the lab.

''There are people in the community who were opposed to it before they even heard of it," he said. ''We're never going to be able to change their minds."

Among the critics was Bryony Schwan, of Women's Voices for the Earth, a Missoula-based group. Schwan said she thought it was suspicious that federal officials decided to go ahead with the project less than two weeks after the time expired for the public to make comments on the most recent environmental analysis of the project.

''It's clear the decision was already made," she said. ''The NIH has not taken public comment seriously."

Only a fraction of the proposed, 105,132-square-foot addition will be outfitted to handle the most dangerous pathogens. Most of the lab will consist of other, less protective labs which are more common across the country and types of research labs that already exist at Rocky Mountain Labs.

The new lab could employ up to 100 people and is projected to cost $66.5 million to build. Although the contractor likely to be hired for the project is an international construction company, Bloom said the agency intends to hire as many carpenters and subcontractors from the state as possible.

Like all BL-4 labs, the one proposed for Hamilton is designed to keep researchers from ever coming into contact with the air inside the lab. Researchers must wear special air-proof suits and breathe air pumped into their outfits.

Martz, who visited Rocky Mountain Labs last year before coming out in favor of the project, said she was pleased by Thursday's decision.

''Rocky Mountain Labs is an outstanding facility that is doing research that will benefit us all," she said in a statement.