Dave Hartley
http://www.Asheville-Computer.com
http://www.ioa.com/~davehart
Chemical Weapons: Safe until 2004?
In a December 1994 report, the General Accounting Office questioned an Army assessment that the U.S. chemical weapons stockpile can be safely stored until 2004. This is Congress's latest deadline for the Department of Defense to destroy stockpiled unitary chemical weapons--those that contain a single lethal agent.
Of concern are 478,000 M55 rockets stored at sites in five states and on Johnston Atoll in the Pacific Ocean. According to GAO and technical consultant Sandia National Laboratories in Albuquerque, New Mexico, these stockpiled M55 rockets are unstable as stored and inadequately monitored by the Army, the Department of Defense's lead service in chemical matters. Deadly Sarin
Initially, Congress directed the Department of Defense to destroy M55s and the rest of the stockpile by 30 September 1994. When the Army fell behind in implementing its $8.5 billion on-site incineration program, Congress extended the deadline to 2004 and asked the Army to evaluate the stockpile's physical and chemical integrity. The Army's July 1993 report--based on inspection and laboratory data and old stockpile assessment reports--said the stockpile was safe for now but uncertain beyond 2004. Congress asked GAO to review the Army's estimate and contingency plans if something goes wrong.
Responding to the GAO report and recommendations made in 1994 by the National Research Council, the Army Chemical Demilitarization and Remediation Activity, based at Aberdeen Proving Ground, Maryland, released a statement February 16 that said work would begin in fiscal year 1995 to determine the storage life of leaking and nonleaking M55 rockets.
Each M55 rocket consists of a warhead that carries 10 pounds of nerve agent (GB) and an explosive charge, and a solid-rocket motor with a nitroglycerin-based propellant and a stabilizer that keeps heat from building up as the propellant decomposes. If the decomposing propellant gets too hot or acidic, the M55 could autoignite.
All stockpiled weapons contain a mustard/blister agent (H) or one of two nerve agents (VX or GB). M55s carry GB, and, the Army report adds, nerve agents, especially GB, become acidic over time and can corrode metal warheads of rockets, mortars, and projectiles.
"The propellant is unstable and so is the chemical agent," says Donna Heivilin, GAO's director of Defense Management and NASA section and author of the 1994 report to Congress, "and the M55 design makes it hard to physically separate the propellant from the GB. If the propellant blows up, the chemical agent would disperse. This is what makes the M55 more dangerous [than other stockpile weapons]."
Threats to stockpile storage include earthquakes, plane crashes, tornadoes, accidents during handling and maintenance, autoignition of the propellant, and chemical leaks from the warhead. And the potential danger to human life is immense, even if one rocket ignited, because, according to the Army's 1994 report, M55 Rocket Storage Life Evaluation, "the resulting explosion and fire in a storage igloo could involve many of the 4,000 rockets that typically are stored together."
"The congressional mandate is that the Army dispose of these [unitary chemical weapons] in the safest, most environmentally sound fashion," says Craig Williams, national spokesperson for the Chemical Weapons Working Group, an international coalition of environmental and ecological groups. "But the Army's focus is on the comparative risk of continued storage versus incineration. We've been trying for years to broaden the scope of that analysis to include comparisons among continued storage, reconfiguration, reconfiguration with partial neutralization, and incineration."
Reconfiguration, Williams says, "involves moving the M55s to a munitions detonation-containment building, using robots to disassemble the munitions, separating chemical agents from other components, and partially neutralizing the by-products. Then we'd have hazardous waste, which isn't great. But what we have now are rockets and mortars ready to launch and send nerve agents randomly into communities. We'd have reduced the risk of exposing chemical warfare agents to facility workers and the community to zero."
At the Army Chemical Demilitarization and Remediation Activity at Aberdeen Proving Ground, Mark Evans, special assistant to the program manager, says this is easier than it sounds. To neutralize the M55s, he says, "we'd have to build 90 percent of the demilitarization [high temperature incinerator] facility we plan to build anyway. We are updating cost estimates for rocket separation, but there are no good neutralization techniques for VX and GB, and we'd produce a lot of waste. The Army believes that if the risk assessments show the rockets can be stored through 2013, our incineration program is the safest method."
The neutralization proposal seems to indicate that construction of the demilitarization facilities could be sped up, but that's not true, according to Evans. A facility at Tooele Army Depot in Utah is built and is in testing, Johnston Atoll's facility is operational, and there are contracts to build and operate facilities at Anniston Army Depot in Alabama (to be completed in 1999), Umatilla Depot Activity in Oregon, and Pine Bluff Arsenal in Arizona (both to be completed in 2000). The Blue Grass Army Depot facility in Kentucky would be operational by 2002.
Over the next year, the Army will examine two approaches for determining the storage life of nonleaking M55s. The Army's approach combines relatively new data on propellant chemistry with a probabilistic method for evaluating storage life. According to this method, the chances of autoignition are less than one in a million before 2013. A second method derived by Hercules Corporation, the propellant manufacturer, estimates the chances of auto-ignition are less than one in a million before 2043.
There are no estimates on autoignition for leaking M55s, which have been found at all six munitions storage sites. Such leaks, caused by corrosion that eats small holes in the metal warheads, let chemicals or vapors escape inside or outside the weapon. External leaks can be quickly detected by monitoring. Internal leaks can't be detected without disassembling the weapon, and a 1985 Army assessment of M55 rockets estimated that 1-3% had internal leaks.
But no one knows the extent of the hazard these leaks pose; the GAO report says the Army has never sampled the leaking munitions because it considers them too dangerous. The Army says there is insufficient evidence to determine, as the GAO report concluded, that leaking rockets have a shorter storage life than nonleaking rockets.
"It is not known if leaking M55 rockets could autoignite during handling if agent were to come in contact with energetic material found in the burster and fuse," the Army statement says. "Previous assessments of the stockpile stability have raised the possibility, but there is insufficient data to reach a conclusive determination. The Army will determine what effects, if any, the agent has on energetic material."
Responding to GAO's call for a contingency plan for emergency disposal of the M55, the Army says it will develop a plan that outlines the steps it will take if the rockets' deterioration accelerates.
Sandia further recommended that the Army immediately expand its stockpile monitoring to include propellant samples from nonleaking and leaking munitions at each storage location. But the Army, whose safe-storage-life projections of nonleaking M55s are based on measuring master samples of rocket propellant stored at Picatinny Arsenal in New Jersey, says it will continue using master samples for periodic assessments after it verifies the master samples still represent propellant stored in the field.
Master samples are used, Evans says, because "we have to think about putting workers at risk who extract propellant sample from fully loaded chemical munitions. We use machines to cut the rounds apart in a room with 28-inch-thick walls because of the potential for problems."
The Army tests will include taking field samples from Tooele, where some rockets were partially dissassembled years ago, and from Johnston Atoll, where some of the rockets have leaked.
"If we do all those tests," says Evans, "and the propellant is different from the master samples, we'll need to initiate a much more extensive field-sampling program, and that will cost a lot of money. If we believe it's different and worse, you may see us try to expedite activities at rocket sites." GAO agrees samples should be taken from all sites, but says expanded monitoring won't answer all questions about stockpile stability.
"We have reason to believe that propellant and agent affect each other, but we don't know if it changes anything," Evans adds. "Only one data point indicates that it may. We need to move from 'it may' to 'it does' or 'it doesn't.'"
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The organophosphate sarin (isopropyl methyl phosphonofluoridate), also known as GB, has been identified as a component of the gas used in the attack. Sarin was first developed in Nazi Germany. At lethal doses, it can cause death within seconds when inhaled. At more moderate doses, it can cause nausea, diarrhea, and interfere with mental ability. Sarin primarily affects the respiratory and nervous systems (see Munro et al., EHP 102:18-38). Subtle changes in EEG patterns and increases in rapid eye movement during sleep were observed in a group of workers one to six years after accidental exposure. Brain damage has resulted at concentrations of sarin high enough to induce convulsions. Respiratory effects include bronchoconstriction, wheezing, and increased airway secretions. Like other organophosphorus compounds, sarin works by inhibiting acetylcholinesterase, an enzyme that breaks down the neurotransmitter acetylcholine, thus overstimulating the nervous system. Once sarin enters the blood, it can penetrate the blood-brain barrier. In the case of sarin, death is caused by depression of the brain's respiratory center. Pupil constriction, or miosis, has been observed up to 60 days after exposure to sarin. Eye pain and dim vision may also occur. Transient, prolonged changes in psychological function, manifested as depression, nightmares, confusion, and deficits in motor skills and intellectual ability have been observed in individuals exposed to organophosphate insecticides, which are similar in structure to sarin. However, unlike some organophosphate insecticides, long-term effects have not been documented for sarin. "Sarin itself should not cause any long-term health effects," said Nancy Munro of the Oak Ridge National Laboratory in Oak Ridge, Tennessee. "[It is] highly unlikely to cause carcinogenicity." Indeed, studies have shown that sarin is neither carcinogenic, genotoxic, or teratogenic. Delayed effects such as organophosphorus-induced delayed neuropathy (OPIDN) may be more of a concern. Although OPIDN has not been associated with sarin exposure, it has been documented in people exposed to organophosphate insecticides. OPIDN usually occurs within 5-30 days of exposure, beginning with weakness, tingling, and muscle twitching, and progressing to paralysis of the toes, hands, and thighs. Recovery is slow and incomplete. The problem, according to Michael Ellis of the University of Texas Medical Branch Poison Center in Galveston, is that organophosphorus compounds accumulate in lipid tissues such as fat and nerves. But, like Munro, Ellis emphasizes that long-term effects are not the concern with sarin: "This stuff was made to kill people," he says. The ease of concocting deadly agents such as sarin has stimulated questions about public safety worldwide. |
