Northern New Mexicans are used to having plutonium in their back yard: Their neighbor on "the hill" is a nuclear weapons lab.

But now the prospect of having live anthrax and other deadly germs at Los Alamos National Laboratory is giving some residents the creeps.

The lab wants to build a research facility where scientists would work with live infectious agents such as plague, anthrax and tuberculosis.

The new, more secure unit — called a biosafety level 3, or BSL-3, lab — would be the only such lab in the Department of Energy's complex and could give Los Alamos a bigger role in the nation's burgeoning fight against bioterrorism.

The lab's Bioscience Division already has done some detective work for the government on the recent anthrax attacks, using sophisticated DNA detection technologies.

But scientists are restricted to working with less-dangerous vaccine or research strains, rather than live anthrax.

And division leader Jill Trewhella complains that having to rely on other labs for their samples is slow and inefficient and heightens the chances for contamination.

"We need to be able to work with small amounts of the live pathogen," Trewhella said.

Critics, however, worry about safety.

"It's the public that could be placed in jeopardy if anything went wrong at this bio lab," said Peggy Prince of Santa Fe-based Peace Action New Mexico.

They're also concerned about putting a bioweapons research lab at a secretive nuclear weapons facility — sequestered, they say, from public scrutiny.

And they fear that what would start out as defensive work could some day be turned into an offensive program, with the lab a logical place to "weaponize" germs.

"I believe that if this laboratory is built, it will be inevitable that the United States will create offensive biological weapons," said Greg Mello, director of the watchdog Los Alamos Study Group. "The technological pressures will be immense."

Opponents aired their concerns to a group of DOE and lab employees who gathered in the conference room of a Los Alamos motel this week for an informal question-and-answer session with the public.

The officials noted that BSL-3 labs — typically found at universities, hospitals or pharmaceutical research centers — are designed and engineered for safety, according to federal standards.

A special air-handling system would keep air flowing in, and filter it as it left. Biologists in gowns, gloves and booties would work with amounts of pathogens typically the size of the lead visible in a sharpened pencil, they said.

"I know these people. I trust these people to protect me and protect themselves," said Jim Brainard, deputy division leader of the Bioscience Division, as he looked around the room at his colleagues.

The three proposed locations for the new lab — the site isn't determined -- are in areas of Los Alamos National Laboratory accessible to the public, "so people can come and visit, and take the message out that it's really defensive, not offensive," Brainard said.

In informal discussions at small, round tables, lab workers were peppered with questions: Why here? Why now? At what cost? What control do you, the scientists, have over the type of work? What are the health implications?

"The record is replete with hiding the health effects of our nuclear weapons program on our military, our civilians, our workers," said Cathie Sullivan, a Santa Fe silkscreen printer who has been keeping an eye on Los Alamos operations for more than 20 years.

Chris Mechels, a retired computer scientist who worked for Los Alamos for 11 years, said the biological research work shouldn't be done within DOE, "because they don't have an adequate concern for worker safety or the safety of the public." A recent report by the Department of Energy proposes a $3.5 million, 3,000-square-foot permanent building that would house three labs — two small BSL-3 labs on either side of a lower-level, BSL-2 lab — as well as office space.

As alternatives, prefabricated structures could be considered, either as a permanent lab or for temporary use while a permanent lab was being built, the report said.

Officials say they hope to have the new lab up and running by spring 2003.

Opponents say the Department of Energy is moving too quickly on the proposal. By the end of this year, a DOE review team could recommend whether to proceed with it.

"We need to have the capability within the department to culture bacteria, so we can extract enough DNA from the samples to do the kinds of tests we need to do," said Elizabeth Withers, a DOE employee in charge of making sure that the lab project gets sufficient environmental scrutiny.

A DOE Office of Inspector General report last February criticized the agency's work with biological agents for not being well enough organized or coordinated. The DOE's Albuquerque office, it said, was unaware of the anthrax experiments under way at Los Alamos.

Trewhella, however, noted that the report also found that there had been no harm to the safety and health of DOE employees or contractors, or to the public. Communications were improved as a result of the report, she said.

"It's something that just made our work better," she said.