Destroying VX

  It seemed so straightforward. neutralize the 1,269 tons of VX nerve agent stored in bulk at Newport, Ind., with sodium hydroxide and then biodegrade the resulting waste product. But nothing in the Army’s program to comply with the Chemical Weapons Convention and meet the treaty’s 2007 deadline for destroying all chemical weapons has been simple or straightforward. Destroying Newport’s stockpile is no exception. Initially, the Army planned to neutralize VX and treat the resulting waste on-site. That would have meant construction of a treatment plant—a time-consuming and costly project. In the aftermath of the terror attacks of Sept. 11, 2001, the Army reconsidered its plan and concluded, for national security reasons, that the neutralized by-products should be shipped off site for immediate treatment at existing commercial facilities. That decision triggered the now-to-be-expected NIMBY—not in my backyard—response.

When the nerve agent is neutralized with sodium hydroxide, the main reaction cleaves VX into sodium 2-(diisopropylamino)ethanethiolate—thiolamine, for short—and sodium ethyl methylphosphonate (NaEMPA). This base-promoted hydrolysis destroys up to 88% of the VX.

A side reaction, which destroys the remaining VX, splits the nerve agent into sodium S-[2-(diisopropylamino)ethyl]methylphosphonothiolate, also called NaEA2192, and ethanol. Under the reaction conditions, NaEA2192 is further hydrolyzed to thiolamine and disodium methyl phosphonate, also known as Na2MPA.

According to the Army, no residual VX remains in the hydrolysate. Still, every batch of hydrolysate produced is to be run through gas chromatography/mass spectrometry analysis to confirm that it is, in Army parlance, “nondetect for VX.” Nondetect translates to less than 20 ppb of VX.

The Army had originally planned to transport the hydrolysate containing the breakdown products to Perma-Fix of Dayton’s commercial wastewater treatment facility, in Ohio. Community opposition, congressional hearings, and a lawsuit forced the Army to back away from this plan.

ENTER DUPONT’S Chambers Works treatment facility in Deepwater, N.J. After regrouping, the Army lighted on DuPont’s Secure Environmental Treatment unit, which can treat the waste, or hydrolysate, biologically.

In anticipation of bidding for the Army contract to transport and treat the hydrolysate and then release the resulting effluent into the Delaware River, DuPont conducted research and produced a 350-page study. The four-part study was reviewed by scientists at Virginia Institute of Marine Science and Virginia Polytechnic Institute & State University, and by the Centers for Disease Control & Prevention. It concluded that transportation of the hydrolysate was safe, and ultimate disposal of the biodegraded waste would be environmentally sound. In short, a DuPont press advisory said, the project “posed no unique hazards.”

A summary of the DuPont study seemed to imply that CDC had read—and approved—the entire 350 pages. Although the university scientists found no problems with the environmental aspects of the DuPont study, CDC had, in fact, raised several concerns about the company’s assessment of potential health risks.

The DuPont press advisory said all “comments were reviewed, assessed, and incorporated as appropriate to improve the quality and accuracy of the final specific technical assessments.” It is unclear, however, how CDC’s comments were treated.

Jeff Lindblad, a spokesman for the Army’s Chemical Materials Agency, tells C&EN that “DuPont has responded to CDC in writing and CDC has that response,” which it is now reviewing. In the meantime, DuPont has amended the summary of its report to correct any misimpressions of CDC’s role, and the Army is receiving comments until April 19 on its plan to ship the waste off site for further treatment.

DuPont spokesman Anthony R. Farina says his company’s role is to assist in “the national security initiative” to destroy the U.S. chemical arsenal. DuPont, he says, “has unique safety and technical capabilities to help in this initiative, and would not engage in this unless it could safely and effectively treat the wastewater with no adverse impact on our employees, the community, and the environment.”

AFFECTED COMMUNITIES and environmental activists see it differently. At recent Army-led informational sessions, citizens from New Jersey and Delaware expressed opposition to the Army’s plan. And the environmental group Green Delaware argued in a recent alert that MPA and EMPA could pollute the Delaware River and “could potentially be reconverted to VX nerve agent.”

Green Delaware recognizes “that the VX and other chemical weapons need to be destroyed as soon as possible.” But the group is emphatic that “the Army needs to return to its original plans for on-site treatment.”

Alan J. Muller, head of Green Delaware, tells C&EN that his group and others will file lawsuits if the Army lets the contract to DuPont. The suits “will allege violation of the National Environmental Policy Act,” he says. “A full environmental impact assessment is required under NEPA, and in our view one has not been done.”

Muller cites the Army’s retreat from its Dayton, Ohio, plan as a precedent. “We hope and expect the Army is going to come to its senses and back out.”

Jesse L. Barber, the Army’s project manager for alternative technologies and approaches, says the Army’s goal is to start neutralizing VX at Newport this July or August and send the hydrolysate to New Jersey for further treatment. “If everything goes smoothly, we will be finished in two years,” he says. “The greatest risk to the country is continued storage of the agent,” he tells C&EN.

If, at the end of the April comment period, no contract is let, Barber’s backup plan “is to go to long-term storage” of the hydrolysate on-site “and to evaluate technologies available to treat the wastewater on-site.”

“I’ve already started looking at alternatives,” Barber says. These include chemical oxidation processes, supercritical water oxidation, and on-site biodegradation.

“My desire is not to have to destroy the waste on-site,” Barber says. However, he reiterates, “the greatest risk to the country is storing the nerve agent, and I’d rather get rid of the agent and store the waste on-site” until a further treatment technology is chosen.

Because of a quirk in State Department policy, the Army won’t meet the chemical weapons treaty deadline of 2007 if the VX hydrolysate is stored, Barber says. Under existing policy, the U.S. will not get credit for destruction if the waste is not also destroyed. So, he says, the Defense Department is asking the State Department to reconsider its policy.