Parker said the Army does not oppose chemical neutralization but was simply taking a pragmatic approach.

"Incineration was a much more mature technology in the late '80s and early '90s," he said. "The department was put in an impossible bind. The Congress mandated some very aggressive disposal schedules, and in order to comply with the law the department pursued the single option that was available, which was to use incineration technology."

The approach has produced mixed results. Chemical agents have escaped three times from incinerator plant stacks and twice from plant equipment, Parker said, adding that the release exceeded the permitted federal standard only once.

But critics such as Jason Groenewold, executive director of the Salt Lake City-based Healthy Environmental Alliance of Utah, said those chemical releases, such as one from Utah's Tooele Chemical Agent Disposal Facility, add to air pollution and could have long-term effects on residents.

"On all accounts we were misled," Groenewold said. "We've had tremendous delays and problems."

The federal Centers for Disease Control and Prevention monitors the public health impact of the chemical weapons disposal, and its officials remain confident that incinerators do not pose a threat and are no more dangerous than chemical neutralization.

But some community activists question that. Two mathematics professors at Berea College, a liberal-arts school near one of the planned disposal facilities, constructed a computer model 10 years ago to determine how dioxins released from the proposed incinerator would affect families in the area. Jan Pearce and James Blackburn-Lynch determined that when it rained, subsistence farmers living near the incinerator would accumulate dioxins in their fatty tissues that would exceed the federal legal limit.