The Army has concluded that a new plant to destroy aging chemical arms at Tooele Army Depot poses no threat to the environment - as long as no accidents occur.

But it admits that remotely possible accidents could kill more than 2,000 people and spread nerve gas to the Salt Lake and Provo areas.Still, the just-released final environmental impact statement for the arms destruction plant says even worse accidents are possible if the Army simply continues to store and not destroy the deteriorating arms - 784 of which at Tooele are leaking.

As in earlier drafts, the Army said such accidents could kill 30,000 people and spread nerve agent as far away as Ogden and Nephi.

The safety of the proposed plant was questioned by a recent Deseret News investigation that revealed that a pilot plant at Tooele - which developed the process to be used by the new plant - had eight accidents between 1983 and 1987 that allowed nerve gas to escape in quantities up to 73 times greater than the legal hourly limit.

It also showed that the new plant, construction of which is still scheduled to begin next month, will be mostly built before any lessons learned at the first full-scale pilot plant, at Johnston Atoll in the Pacific, can be incorporated.

The Army sought to quell such questions in its final report pledging to make any modifications it discovers are needed before it will allow the new Tooele plant to begin arms destruction.

The main conclusion of the final report issued by the program manager for chemical demilitarization at Aberdeen Proving Ground, Md., was that Tooele's "stockpile of chemical agents and munitions can be destroyed in a safe and environmentally acceptable manner" in normal operations without accidents.

Tooele stores 42.3 percent of the nation's aging chemical weapons. The Army decided to destroy all such arms by 1997 on-site at the bases where they are stored. They are to be replaced by safer "binary" weapons, which have two chemicals that are safe until mixed in-flight after firing to form nerve gas.

The report said accidents are possible, but highly unlikely. It said the worst accident officials could imagine - and a remote one at that - would be a fire caused by an earthquake hitting during destruction of chemical land mines and rockets with explosives still attached.

That could kill up to 2,040 people, the report estimates, and spread nerve agent up to 31 miles from the plant to be built in Rush Valley. However, even if an earthquake occurs during weapons destruction, the Army says the chance of such a fire is only 1 in 10,000.

The report notes that even more serious accidents are possible through continued storage because the arms are deteriorating with age. It said remotely possible events such as earthquakes or airplane crashes rupturing storage tanks of nerve agent could kill 30,400 people and spread nerve agent 62 miles.

In the final draft of the report, the Army tried to allay fears by some Utah officials that the new plant may not be able to take advantage of any lessons learned by the new pilot plant at Johnston Atoll.

Because of delays, the Johnston plant will not begin tests with live ammunition until next March. Construction of the Tooele plant is to begin in August.