The bland buildings in western Siberia contain shelf after shelf of nerve-gas shells -- some 2 million in all.

Each could kill tens of thousands of people, if exploded in a tightly packed area. Many are small enough to be spirited away in a briefcase.

Since the 1991 collapse of the Soviet Union left Russia's military underfunded and disorganized, the arsenal in Shchuchye, about 1,000 miles east of Moscow, has been a top security concern. After years of delays and disputes, a vast facility to destroy the weapons is to formally open there on Friday.

The plant, the size of a small town, was built with a U.S. contribution of more than $1 billion and is seen as a milestone in cooperation on disarmament between Washington and Moscow.

"It's a signal event in terms of arms control," U.S. Senator Richard Lugar told The Associated Press in a telephone interview.

Lugar and former Sen. Sam Nunn authored the Cooperative Threat Reduction program of 1992 under which the U.S. has poured money into eliminating much of the former Soviet Union's weapons of mass destruction and improving security for the stockpiles that remain.

Russia, as a signatory of the international Chemical Weapons Convention, is obliged to eliminate its vast stores of Class I weapons -- chemicals that have no use other than in arms. Moscow already has destroyed about 30 percent of its stockpile, according to the Russian Munitions Agency.

But the Shchuchye facility significantly boosts destruction capacity. Russian officials claim it will allow the country to meet its treaty obligations of destroying all chemical weapons by 2012, although Lugar said that goal probably won't be met.

Nonetheless, the opening -- which follows preliminary destruction work that began in March -- is significant because of the dangers posed by the weapons. Lugar said some of the shells at Shchuchye could kill 80,000 people if deployed in a stadium.

"This is just deadly stuff, in such huge amounts, and obviously, because of the size of it, portable. The dangers to the international community have been evident," he said.

The opening of the plant comes at a symbolically important time, as Russia and the United States take initial steps toward working out a successor to the START nuclear arms reduction treaty that expires at the end of this year.

The opening also comes as both countries tentatively try to repair relations that deteriorated under the presidencies of George Bush and Vladimir Putin.

But while the project can be seen as a model of long-term cooperation, it also underlines the frequent difficulties that the United States runs into with Russia.

Delays in opening the plant came as disagreements arose over the type of munitions to be destroyed and how to eliminate them. The U.S. General Accounting Office says the hunt for a Russian subcontractor to install equipment at a reasonable cost was alone responsible for pushing the project back a year.

The weapons to be destroyed at Shchuchye contain in total about 5,460 metric tons (6,000 short tons) of nerve agent including sarin and VX; in all, that's about 14 percent of the chemical weapons that Russia is committed to destroy. The initial destruction capacity is roughly 850 metric tons (935 short tons) a year, but the figure is expected to double when a second building at the complex comes into operation at the end of they year.

The welded shells are to be drilled, then drained of their deadly agents. The chemicals will be neutralized then turned into bitumen salt mass, a solid waste that is considered mildly dangerous. That waste is to be stored in drums in concrete-lined bunkers situated above the groundwater level.

The complex, which sprawls across some 250 acres (100 acres) is about 16 kilometers (10 miles) from the buildings where the shells are stored. The weapons will be transported there on a specially built railroad.