An Army plan to ship wastewater from a nerve agent disposal project to a DuPont Co. plant along the Delaware River remains on hold despite a decision to start full-scale neutralization processes in the spring at the Indiana weapons stockpile.

Under the disposal project, an Army contractor will use hot water and a drain-cleaner-like compound to neutralize 1,269 tons of VX - a nerve agent considered one of the deadliest chemical weapons on the planet. The process will generate up to 4 million gallons of a caustic liquid called hydrolysate.

"We've gotten the Army's permission to start making our preparations to start in the spring," said Terry A. Arthur, public affairs officer at the Army's Newport Chemical Depot. "Basically, our plan is to go ahead and start processing the chemical agent and store the hydrolysate here while we wait for a resolution" on final disposal.

Officials originally hoped to ship wastewater from the disposal process to DuPont's Secure Environmental Treatment plant at the Chambers Works in Deepwater, N.J., near the foot of the Delaware Memorial Bridge. Delaware and New Jersey both questioned the proposal, however, and the governors of both states urged the military to handle the wastes near the original neutralization plant.

Although the Deepwater plant is in New Jersey, its commercial wastewater plant discharge pipe empties on the bottom of the river inside Delaware waters.

Department of Natural Resources and Environmental Control officials issued a report last year raising concerns about potential harm to the river, pointing out that DuPont's process would send two obscure varieties of phosphorus compounds mostly untreated into the waterway. New Jersey's Department of Environmental Protection said it would require a permit change and new discharge tests if DuPont continued to seek the Army contract.

Some environmental groups have continued to express concern that trace amounts of VX would survive the disposal process and reach the river.

DuPont spokesman Anthony R. Farina said the company plans to send results from a study of a revised treatment process to the Centers for Disease Control and Prevention by the end of the month.

The treatment study and CDC review "must be accomplished before we would agree to be involved in the Army's project," Farina said. "We've said that for several months, and we're committed to that."