Defense Environmental Alert
May 21, 2002

NRC PANEL BACKS ARMY'S PLAN TO EXPEDITE DISPOSAL OF VX AT NEWPORT

An ad hoc National Research Council (NRC) panel last year raised some concerns over the Army's plan to speed up disposal of bulk VX chemical agent stockpiled in Indiana, but overall supported the concept, according to a December NRC letter report released this month.

An Army spokesman says the military has decided against adopting the portion of the plan that prompted the most concern for the panel --- in situ neutralization -- and instead is focusing on an approach that modifies the Anny's original plan of using sodium hydroxide, a caustic, to neutralize the VX in mixing tanks. The approach is similar to the Army's plan to expedite disposal of bulk mustard agent at Aberdeen, MD (Defense Environment Alert, May 7, p16). Under both scenarios, the Army would ship the resulting secondary wastes, known as hydrolysate, to an off-site treatment facility.

When the Army's project manager for alternative technologies and approaches briefed the NRC panel in late November, the military was considering two options that would conceivably achieve neutralization of the VX by the fall of 2002, although the NRC notes in its Dec. 21, 2001, letter report that even at the time of the briefing. that schedule had slipped. The spokesman says the plan now is to begin disposal operations in July 2003 and be finished with neutralization by February 2004. An environmental assessment on off-site disposal is expected to be released for public comment in July, he says.

The first option was in situ neutralization where water would be added at a controlled rate into the existing containers. with nitrogen added to aid the neutralization process. But the NRC panel says that when this approach was studied in 1996, the NRC identified a number of problems, including hot spots, the formation of gel, and the creation of EA-2192, a toxic by-product of water hydrolysis.

The second option, which the NRC in its letter report urged the Army to pursue and to which the Army is now devoting its efforts, provides for draining the ton containers of VX using a vacuum system, followed by a triple rinse. Instead of using an automated procedure to drain the containers, as originally planned, workers will manually insert a vacuum siphon into each ton container using gloves in a box sealed around the container, the NRC and Army say. The agent will then be fed into a reactor where neutralization with sodium hydroxide will take place. The resulting hydrolysate will be stored in tanks and then sent off site for treatment at a commercial facility.

While supportive of this second option, the NRC panel also raised some concerns because the vacuum siphoning process has not been demonstrated. And the panel said workers have a greater chance of exposure to agent because of the increase in manual operations. The Army should "rapidly" undertake an analysis of the risk to workers and the public of longer-term storage of VX agent in ton containers and of the potential added risks of processing using the more rapid, worker-intensive disposal process in modified structures, the panel said. The Army's modified neutralization facility would be less complex than originally planned. The Army provided little data to the panel on the effects of these changes with regard to public safety and the environment.