First it was a landmark, a 365-foot totem of industrial muscle. Then it was an eyesore, a sorry reminder of Virginia's worst modern environmental disaster. And this morning, it became a pile of red-brick rubble, the beginning of the latest phase of an arduous and expensive cleanup.

At 9.50 a.m., 80 pounds of nitroglycerin-based dynamite demolished the 30-story smokestack that towered over the Avtex Fibers plant, a Superfund site and 440-acre smorgasbord of toxins on the bank of the south fork of the Shenandoah River.

"It was totally successful," said Michael Towle, on-scene coordinator for the Environmental Protection Agency, which is overseeing decontamination of the site. "We had very minimal dust."

Towle said the controlled explosion, along with the dousing of the area around the tower with water, had substantially reduced the release of toxins into the air. And, he said, air monitors on the perimeter of the site confirmed that dust from the debris was contained.

Hundreds of people, many of them former employees of what was once the country's largest rayon producer, watched from the perimeter fence a few hundred yards away as the stack fell straight down with a mighty crack, like a soda can crushed by an invisible hand.

"I hate to see it go, but it's got to go," said Perry Chrisman, 73, of nearby Bentonville, who worked at the plant for 32 years and watched the demolition this morning. "That place gave a lot of work to people."

And it also bequeathed Front Royal its poisons: 70 acres of decaying plant suffused with asbestos, PCBs, acids, mercury, lead and carbon disulfide, a yellowish explosive material that causes nerve damage; small hills of coal ash with trees and brush growing from the soft black soil; sections of moonscape-like land created by waste sulfides; and 200 acres of chemically loaded lagoons and sludge pools right on the bank of the river.

Strangely, throughout the site's ghostly remains, deer, fox, beaver and other wildlife are making this cesspool their home.

In the shadow of the Blue Ridge Mountains, the plant was once Front Royal's principal employer, with 3,000 workers at its peak. After opening in the 1930s, it manufactured rayon for tires during World War II and later produced rayon for rocket nozzles for the Defense Department and the National Aeronautics and Space Administration.

In 1989, with the company struggling against foreign competition, the state revoked Avtex's water permit, citing 2,000 pollution violations. The plant had been listed as a Superfund site in 1986. Avtex immediately declared bankruptcy and abandoned the property without making any attempt to clean it up. The case is still in U.S. Bankruptcy Court in Pennsylvania.

The EPA has spent $27 million since the early 1980s cleaning up the site -- treating, recycling and removing 8,000 tons of contaminated soil, 2,000 tons of chemicals, 241,000 gallons of flammable and acidic chemicals and 3,000 bags of asbestos, to name just a few measures undertaken.

Under federal order, FMC Corp., a Chicago-based concern that owned the site from 1963 to 1976, has treated a billion gallons of wastewater. Avtex bought the plant from FMC in 1976. The plant was originally built by the American Viscose Corp.

Today's demolition begins a projected two years and $33 million of work to take down about half the buildings -- the ones most contaminated. The work to clean the rest of the site will stretch well into the next century, and officials have estimated that the final cleanup bill will top $100 million.

Virginia sued the federal government and FMC Corp. in February to recover its expenditures involving Avtex. Virginia alleged that the federal government was as responsible for the pollution as the private operators of the site because it knew what was happening for years, did nothing to prevent it and even made an attempt in the late 1980s to keep the plant open.

FMC Corp., NASA, the Defense Department, the Air Force and the Commerce Department formally agreed last week to reimburse $1.1 million, all of Virginia's past costs, with the payment split equally between the corporation and the government.

The federal government, through the Superfund, is paying for the cleanup, but it has reserved the right to sue FMC to recover some of its costs if it does not reach a negotiated settlement with the chemical company and defense contractor.

"It's good to see that eyesore finally gone," said Mark Yates, 34, of Front Royal, as he stood in the bed of a pickup truck shortly after watching the smokestack fall. "I applied for a job over there, but thank God I never got hired." CAPTION: A Symbol Of Pollution Is No More Cameras rolling, onlookers view the demolition of the 30-story smokestack of the the former Avtex Fibers plant, a Superfund site on Virginia's Shenandoah River. At left, after the blast, Front Royal firefighters Scott Curry, left, Jeff Neal, Brian Whited and Brian Pugh hold souvenir bricks. The federal government has spent $27 million cleaning up the toxic site, a job that is far from finished. Story on Page B5.