The river, which originates in New York and touches Pennsylvania, New Jersey, and Delaware on its way to the Atlantic, has in recent years made a remarkable comeback from the industrial pollutants that once fouled it. And the river has some fierce defenders, including an organization called the Delaware Riverkeeper Network.

When the C.M.A.'s legal notice came to the attention of Tracy Carluccio, the group's deputy director, she immediately asked the Army what it was up to. The answer—using the river to dispose of nerve-agent residue—shocked her. "What the Army was proposing to do," Carluccio says, "was absolutely outrageous."

Carluccio and her group formed a coalition to oppose the plan. But her outrage was nothing compared with the wrath of New Jersey lawmakers, including Representative Robert Andrews, a Democrat whose district straddles a part of the Delaware River watershed.

Andrews sits on the House Armed Services Committee and "though the river runs through my district, no one ever told me or the elected officials who represent our area that this was even under consideration," he says.

The Army had another fight on its hands.

Congress took steps to delay the project while asking the Government Accountability Office to review the plan. The governor of New Jersey pledged to physically block nerve-agent residue shipments on the New Jersey Turnpike. Then, in December 2006, the Delaware Riverkeepers, the New Jersey Audubon Society, and others filed suit in Federal District Court in Washington. They alleged that the Army's plan violated all manner of federal laws, including bans on shipping of chemical agents across state lines.

This was too much for DuPont; in early January 2007, the company backed out, saying "it has become increasingly clear to us that the regulatory process will be lengthy and arduous....Therefore, we believe it is in the best interest of ...DuPont not to proceed." The company declined further comment for this story.

After the Dayton and DuPont debacles, the Army scrambled to find a new home for the processed VX, and settled on Port Arthur. According to Veolia and Army officials, the plant there was already permitted by the state of Texas to dispose of chemicals like sodium hydrolysate.

Although neither Army nor Veolia officials will say it, there's another compelling reason to select Port Arthur: The blue-collar city's economic fortunes are already tied to the chemical plants and oil- and gas-processing facilities there.

Port Arthur has environmental and community activists, but they're not nearly as numerous, well-funded, or politically connected as are the Dayton and New Jersey groups.

And by this time, the Army had finally seemed to learn a lesson: It agreed it was best to do some outreach to first sell the plan. It also decided it would be best if the Army itself stayed out of it. So in February 2007, only a month after the New Jersey fiasco, Veolia's Duncan, Osborne, and others spent five weeks briefing state and local officials about the project.

This was not a tour that included public hearings or press briefings, however. When the story leaked in a local newspaper, another firestorm erupted.

But Veolia had two things that neither DuPont nor Parsons could produce: a permit to dispose of the VX residue, and a claim that it had at least briefed some of the people who needed to know.

That didn't stop the Sierra Club and others from asking a federal court in Indiana to block the Newport shipments. A judge in late September rejected that request, ruling that the plan didn't violate federal or state laws.

Still, bitter feelings remain. "Surely we were hoodwinked," says Port Arthur city councilman Martin Flood, who was not among the officials briefed in advance.

Veolia's general manager, Osborne, says his company did what it could. "Could I sit here and tell you that we could have done more and briefed more people? Sure," he says. "But would that have alleviated some of the concern or stopped the misinformation from various entities? I don't know."

Later, Duncan weighs in. "We thought that if had we handled it any differently, we might have jeopardized the project."