As the FBI arrested two men in a Las Vegas suburb Thursday for allegedly possessing deadly anthrax bacteria for use as a weapon, it turned to some Utah germ warfare experts for help.

The Army's Dugway Proving Ground, somewhat noted for past open-air tests of agents, including anthrax, responded by sending a lab technician, plus four members of a highly trained but little-known special response unit.Arrested in Henderson, Nev., were Larry Wayne Harris, 46, Lancaster, Ohio, and William Leavitt, 47, Las Vegas and Logandale, Nev. They were charged in federal court with possessing a deadly germ for use as a weapon.

In an affidavit, the FBI wrote that Harris is a white supremacist who talked last summer about a plan to release bubonic plague on New York City subways, causing "hundreds of thousands of deaths" in a massacre that would ruin the economy, surprise the military and be blamed on the Iraqis.

A detention hearing for the two was delayed until Monday while the government runs tests to determine if they had anthrax of military grade or an anthrax livestock vaccine.

Among those at Las Vegas, presumably to help with containment or testing, was the Army Technical Escort Unit, which has quietly handled germ and chemical weapons threats at Olympics, presidential inaugurations and political party conventions.

While it is technically based at Aberdeen Proving Ground, Md., the escort unit keeps a small detachment at Dugway. Four highly trained soldiers from the unit were sent to help in Las Vegas, said Susan Fournier, spokeswoman for the U.S. Army Chemical and Biological Command.

Pentagon and Aberdeen spokesmen did not say what specific work the unit is conducting in Las Vegas.

But an Army fact sheet on the unit said it is sent worldwide to help render suspected germ and chemical weapons safe; to sample and verify exactly what worrisome materials are; to escort dangerous matter; and to mitigate hazards.

The unit was formed in 1944, and now is the longest continuously active military chemical unit in existence.

The Army fact sheet said the unit "has been called to respond to potential chemical biological incidents in the United States at national events, such as the Olympics, political party conventions, and at the presidential inauguration."

Among the agencies that have requested assistance from it through the years, according to the fact sheet, are: the United Nations; "other intelligence communities"; the Secret Service; the State Department; the Environmental Protection Agency; the Federal Emergency Management Agency; and the Energy Department.

The unit also helped destroy numerous chemical weapons stockpiles in Iraq after the Persian Gulf War.

Among other situations it has handled recently are: a buried cache of World War I chemical munitions found in a residential area of Washington, D.C., in 1993; a cache of buried biological bomblets found at Wright-Patterson Air Force Base, Ohio, in 1995; and caches of chemical agent ampules found last year at Fort Ord, Calif., and Fort Polk, La.

The special unit can quickly mobilize state-of-the-art detection, monitoring and protection equipment - including support laboratories. Members have widely varied and specialized training in explosives handling, radiography, handling of hazardous materials and medical response.

The unit also has sophisticated protective clothing, materials to overpack hazardous materials and portable satellite terminals to provide worldwide voice, fax and data links with other experts.

Historically, Dugway has been the site where the Army has developed and tested much of its expertise on germ and chemical warfare and defenses. Some of the mission, including work with anthrax, has been controversial.

Research by the Deseret News in 1994 showed that Dugway had 328 open-air germ tests there through the years (plus 74 radiological arms tests, eight simulated nuclear reactor meltdowns and 1,174 open-air tests of chemical agents). Agents from many such tests blew off the base.

Those open-air tests included three series with anthrax bacteria that began in January 1954 and ended in February 1956.

The Army designated the area where anthrax had been tested as a "permanent biologically contaminated area" on maps because anthrax forms spores that remain potent indefinitely.

However, that designation was later removed after testing in the area failed to find any contamination. Harold Hodge, a former commander of Dugway, has com-plained that the move was unwise.

"It is not possible to decontaminate anthrax spores. They live in the soil and stay there - and are dangerous to humans as well as horses (a wild herd of horses roams Dugway)." He is quoted in the book "Germ Wars," by investigative journalist Charles Piller and microbiologist Keith R. Yam-a-moto.

Also of note, the FBI said the men arrested in Las Vegas Thursday had talked about planning to spread anthrax in the subways of New York City.

The Army itself once did something similar. In 1966, it used the same subway to spread bacillus subtilis variant niger - a germ then considered safe to most people but found to pose risk to the sick, elderly and infants.

Army test personnel smashed light bulbs full of the germ there, spreading trillions of germs over four days during peak travel hours in June 1966 to see how well such germ agents spread. That sparked later criticism that it used New Yorkers as human guinea pigs with-out their knowledge.