This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Chemical warfare has long been banned from the battlefield, but safely eliminating the world's aging mustard gas, sarin and other chemical weapon stockpiles has proven difficult. Although the U.S. military has been working with Defense Department contractors for more than a decade to develop technology that could neutralize its chemical arsenal without the need for detonation, the Associated Press recently reports that the Army is now proposing the use of explosives to destroy some of the 125,000 weapons being stored at chemical depots in Colorado and Kentucky. This might speed the process some, but the Army acknowledges that it will still miss the 2012 deadline set by Congress in 1997.
Not surprisingly, residents in and around the Army's Pueblo Chemical Depot in Colorado and Blue Grass Army Depot in Richmond, Ky., are nonplussed with the military's proposed approach, saying that blowing up these weapons would be even worse than a previous plan to burn them at high temperatures, according to the AP. The residents want the military to revert to its original proposal of mixing the toxic chemicals with water, bacteria or other substances that neutralize the poison and then carting them off to a hazardous waste dump.
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The Army's plan to reduce its chemical weapons arsenal by blowing up part of it is less a matter of an expedience than an admission that the military hasn't found a better way of dealing with the problem. "I wouldn't say [detonation] provides much acceleration," Kevin Flamm, the Army's program manager for neutralization operations at Pueblo and blue Grass, said during briefings in December, according to the AP. Although the Army wanted to find an alternative to blowing up its chemical weapons, Flamm says, "Frankly there isn't any other technologies we've found that can eliminate these weapons safely and environmentally friendly in the time frame we're looking at."
The Army's Chemical Materials Agency attempted to develop technology to help it comply with the 1997 Chemical Weapons Convention, an international treaty the U.S. and more than 150 other nations signed as their pledge to rid the world of chemical weapons. In Pueblo, Defense Department contractors had been developing a process called "neutralization followed by biotreatment," which relied on hot water to destroy mustard agent molecules, turning the toxic chemical into a substance that is readily biodegradable and could be broken down with microbes such as those used to treat sewage.
In Kentucky, the Army began experimenting with "neutralization followed by supercritical water oxidation" in 2003 as a way to counteract the effects of the toxic substances in the weapons. In "neutralization followed by supercritical water oxidation," the toxic agents are separated out and destroyed using water. The resulting solution is fed to supercritical water oxidation units that subject the solution to very high temperatures and pressures, breaking them down into carbon dioxide, water and salts. While Pueblo houses mostly mustard, Blue Grass is home to mustard as well as GB and VX nerve gasses (GB is better known as sarin).
Chemical leaks are not uncommon at these sites. In November, chemical crews at Pueblo wrapped up a two-month operation to seal a mustard leak, according to the Army Chemical Materials Agency's Web site. The mustard vapor was detected in August by mobile monitoring equipment designed to analyze air inside the storage structures. Chemical crews transferred the munitions into larger sealed containers.
In June, sarin nerve gas was detected at Blue Grass. The leak consisted of a "small, barely detectable, amount liquid GB [sarin] coming from one of the rockets," the Army Chemical Materials Agency reported on its Web site. Toxic chemical workers found the leaking munition during a physical inspection of the rocket's holding container and reported that none of the agent could have escaped outside the facility.
Image chemical weapons stored at Pueblo Chemical Depot courtesy of the Army Chemical Materials Agency
