January 24, 2012: The United States has destroyed about 90 percent of its Cold War era chemical weapons stockpile. Recently, the last of 13,600 tons of chemical munitions were destroyed at the U.S. Army Deseret Chemical Depot in Utah. This depot mainly held Mustard, Lewisite, and other corrosive chemical agents. The most fearsome chemical agent, nerve gas, had first priority in this destruction effort. Three years ago the U.S. completed the destruction of the last of its nerve gas weapons stored in the United States. That 66 month effort destroyed 293,000 gallons (over a million liters) of VX and Sarin nerve agent by incineration. These weapons were stored, for nearly half a century, in underground bunkers in the Anniston Army Depot, 80 kilometers east of Birmingham, Alabama.

Modern chemical weapons were first used during World War I (1914-18), where military leaders quickly discovered that these weapons were more trouble than they were worth. Troop movements were greatly slowed down by the chemicals and morale took an enormous hit. Protective masks and clothing soon appeared and these also slowed down operations. As a result of these shortcomings chemical weapons have not been used by the military since 1918 (except against civilians or troops who could not respond in kind). But just to be on the safe side, everyone stockpiled lots of these weapons during World War II and the Cold War. After the Cold War ended it was agreed that chemical weapons were more trouble than they were worth for military use and the enormous stockpiles were destroyed.

Over the last 21 years the U.S. has been destroying its 31,500 tons of chemical weapons (mainly nerve and mustard gas). The destruction took place at seven sites. Only two of these sites are still operational, destroying the remaining chemical weapons.

Russia is also destroying its own 40,000 tons of chemical weapons. All these weapons were to have been, by treaty, destroyed by 2007 but there have been construction and technical delays. Four years ago, the OPCW (Organization for the Prohibition of Chemical Weapons) admitted that its 1997 deadlines for destroying the world's chemical weapons stocks were too optimistic and has extended that 2007 deadline by five years (to 2012). But Russia reported that it would not be able to meet even that deadline and had to build more destruction plants, which it has done.

The OPCW treaty has 183 nations signed on. But several (Israel, Egypt, Syria, Lebanon, Iraq, and seven others) have not. Despite this, since 1993, nearly half of the world's chemical weapons have been destroyed. This includes nearly all of the U.S. stocks and over half the largest stockpile in the world (Russia).

The 1997 Chemical Weapons Convention treaty, which OPCW monitors, has resulted in 3,000 inspections, in 80 countries, over the last 15 years. The main obstacle to destruction of chemical weapons has been technical. It's not easy to safely destroy this stuff. The U.S. has provided Russia with cash and technology to help them get on with destroying their stocks. For Russia this is somewhat urgent, as the Soviet Union was reluctant to throw away old chemical weapons. As a result, much of the Russian stuff has deteriorated with time, becoming unstable and more difficult to handle. On the plus side, dealing with the Russian stockpiles has advanced the technology for destroying decrepit chemical weapons and produced lots of Russians with technical skills and a willingness to travel and apply these skills, for the right price.

After World War II even larger quantities of chemical weapons were disposed of by simply dumping them into the ocean. This was only a problem in the shallow Baltic, where 35,000 tons of German chemical weapons were dumped. These are coming up in fishing nets and the shells and barrels are corroding and releasing the poisons. This is harmful to the fish and any fishermen who haul it up. A dozen or so fishermen are injured by these ancient chemical weapons each year. While some 50,000 tons of chemical munitions were dumped in the Baltic only about 10,000 tons are actual chemicals. Most of this is stuff like Mustard and Phosgene, which are not as deadly as nerve gas (which degrades much more quickly). The World War I and II era ocean disposal programs involved more than twice as much chemical weapons than are being disposed now. Nerve gas, which degrades quickly in the ocean, takes a lot more time and expense to dispose of on the land (usually via incineration).

All the main chemical weapons (especially mustard and nerve gas) are easy to manufacture for any nation with a few chemical plants (especially one that produces insecticide, which is basically nerve gas for insects). But it can take months to modify the plants and get production going. So the elimination of all these old stocks makes the use of chemical weapons less likely, especially by terrorists.