WASHINGTON – The United States probably won’t meet a 2007 deadline for destroying chemical weapons stockpiles, congressional investigators say, noting that only about 18 percent of the 31,496 tons of nerve gas, mustard gas and other chemicals have been incinerated since the effort began in the 1980s.

The General Accounting Office report also faulted the Army’s management of the $15 billion chemical weapons destruction program. Investigators found $63 million in spending that had not been properly recorded, and Army officials could not explain why $10.4 million appropriated for the program had not been spent, the report said.

Congressional critics asked for the GAO investigation last year after a Pentagon report said the Army had not spent millions of dollars earmarked for chemical weapons destruction, possibly leaving the money available for other uses.

Congress ordered the military to begin destroying America’s 31,496 tons of nerve agents, mustard gas and other chemical weapons in 1986. In 1997, the Senate ratified the international Chemical Weapons Convention, which bans the production, use or stockpiling of chemical weapons.

About 12 percent of the nation’s stockpiled chemical weapons are stored at the Umatilla Chemical Depot west of Hermiston. An incinerator complex is under construction and should be ready for use by early 2002.

The recent GAO report found nearly $500 million in unspent money from 1992 through 1999. The report said most of that money accumulated because of the Pentagon’s sluggish financial systems, because environmental permits were delayed or because contractors had not yet billed the government for their work.

‘There wasn’t any (unspent) money being squirreled away, like some people thought,’ said Mickey Morales, a spokesman for the Army’s Program Manager for Chemical Demilitarization.

According to the report sent to Congress this week, said the United States has destroyed about 18 percent of its stockpile at incinerators in Utah and the South Pacific. The Army also is building facilities to destroy chemical weapons at sites in Oregon, Arkansas, Indiana, Maryland and Alabama.

The treaty requires that countries must have destroyed 1 percent of their chemical weapons stockpiles by now, Morales said.

Area residents and local officials objected to plans to incinerate chemical weapons at the Pueblo Chemical Depot in Colorado and the Blue Grass Army Depot near Richmond, Ky. Congress blocked incineration plans at those sites in 1996, ordering the Army to develop other ways to neutralize and destroy the deadly chemicals. The Army plans to spend $40 million to complete those studies this year.

That delay means that the 10 percent of the U.S. stockpile at the Colorado and Kentucky sites will probably not be destroyed by the treaty’s 2007 deadline, the GAO report said. The treaty has a provision allowing countries to get an extension of up to five years if they cannot meet the deadline.

So far, 135 nations have ratified the chemical weapons treaty and another 36 have said they support it but have not ratified it.