A unique chamber designed to make the United States better prepared in the event of biological attack has opened at a U.S. Army facility in Utah.

The largest such chamber in the world, the installation at the Dugway Proving Ground adds another weapon in the U.S. defensive arsenal against biological agents such as plague, anthrax or ricin, officials say.

Built by the U.S. Department of Defense for $39 million, the research chamber is the result of a 2002 government directive intended to beef up the country's readiness to deal with biological threats.

The chamber, officially dubbed the Whole System Live Agent Test facility, will allow researchers to test how successful biological agent detecting systems are at fulfilling the task they were designed to do, researchers say.

"We have never had a chamber large enough to do whole-system testing," says Douglas Andersen, chief of the life sciences division at Dugway's West Desert System.

Before the Whole System facility was constructed, detection systems had to be tested piecemeal, component by component

The new chamber allows testing of typical systems used by the military, systems about the size of a refrigerator.

The chamber is large enough to hold two such systems, allowing them to be compared side by side, Anderson says.

"We can do those tests and safely challenge or expose a real system to agent in the air and see if it will respond," he says.

Aerosolized particles of an agent will be driven into the chamber using air pressure to simulate different conditions under which they might spread.

This takes place in a building engineered to be always at an overall negative air pressure so no agent can escape beyond the confines of the test chamber.

One new capability the system offers is the ability to manipulate the size of biological agent particles being introduced into the chamber.

"A few years back, no one could control aerosol size, and we have gone from no control to sudden precision," says Dugway scientist Wing Tsang.

After its official ribbon-cutting ceremony Feb. 19, the system is expected to begin live testing operations in the coming weeks.

Officials were quick to point out the advantages the new chamber will provide in the effort to guard against potential biological threats.

"It is a huge deal," says Dugway commander Col. Ronald Fizer. "We have not had the ability to evaluate these systems in a live environment before. This allows us to have a high degree of confidence in our systems."