Abdurrahman Aydın / World Bulletin
After the Baath regime in Syria had allegedly used chemical weapons against the civilian population in the suburbs of Damascus, the US decision makers accused the Syrian government of breaking an international agreement reached at the end of WW I. According to this agreement, chemical weapons are not permitted to be employed in any sort of military conflict. From the way the US leadership speaks, someone who is not familiar with world affairs may think that chemical weapons have not been used in wars from the end of WW I until the attacks of the Baath regime on August 21, 2013. Contrary to the image the US political leadership has been presenting recently, from WW II to today, the US has the lead in the world in the development, production and deployment of chemical weapons on both military forces and civilian populations at home and across the world.
Inside the US
In 2001, the San Francisco Chronicle reported that “at least three times in the past, San Franciscans and other Americans have been inadvertent victims of efforts designed to help shield citizens against attacks.”  In 1950, after the Army secretly sprayed supposedly harmless bacteria over the entire city and its suburbs by using a Navy ship cruising just outside the Golden Gate, germs in San Francisco made eleven people sick, one of whom died later. The CIA sent out agents from 1956 to 1961 to examine the effects of mind-altering drugs such as LSD and synthetic mescaline on unsuspecting people in San Francisco, Mill Valley and other cities across the country, in a secret behavior modification program called MK-ULTRA. Many of the victims hallucinated, many became sick and at least two deaths resulted from the experiments. Furthermore, from 1944 to 1974, hundreds of secret experiments in San Francisco and around the country were conducted by both the Defense Department and the Atomic Energy Commission which exposed unsuspecting patients to dangerous doses of radiation, including injections of plutonium.
By these secret research projects, the military and other federal agencies supposedly aimed at helping to prepare defenses against biological warfare, nuclear terror and mass brainwashing. Besides, in 1951, racist experiments were carried out by U.S. Army researchers by deliberately exposing African-Americans to the fungus Aspergillus fumigatus so as to discern whether they are more susceptible to the infections caused by such organisms than people of white European descent. Also within the same year, black workers at the Norfolk Supply Center in Virginia were exposed to crates contaminated with A. fumigatus spores. And others have followed the suit! 
The US worldwide experience with chemical weapons
During the Korean War, 1950-53, North Korea and China accused the US of using the germ warfare agents they had developed in 1947. A report issued in 1952 by the International Scientific Commission for the Investigation of the Facts Concerning Bacterial Warfare in Korea and China, set up by the Helsinki-based World Peace Council, concluded that “the American Air Force had been employing in Korea methods very similar to, if not exactly identical with, those employed to spread plague by the Japanese during the Second World War. It added that the testimonies of the hundreds of witnesses interviewed for the report were 'too simple, too concordant and too independent’ to be doubted.” The Commission’s report was compiled by experts from Sweden, France, Italy, Brazil and Russia, as well as Dr. Joseph Needham, a respected British authority on Chinese science. 
During the the Vietnam War (1955-1975), the US used Napalm and Agent Orange as their major chemical weapons between 1965 and 1972. The US dropped more than 400,000 tons of Napalm on mostly civilian areas in Vietnam throughout the war.
The US used Agent Orange to destroy crops and water sources. The purpose in this was to drive the Vietnamese out into US controlled areas. The US sprayed 73 million litres of Agent Orange, Blue, Pink, Purple and Green on Vietnam between 1962 and 1970. 24 percent of southern Vietnam was sprayed over, leading to the destruction of 5 million acres of upland and mangrove forests and about 500,000 acres of crops. 34 percent of the previously sprayed areas were targeted more than once. Some of the upland forests were sprayed more than four times. One study found that 3,181 villages were sprayed as well. Areas of Laos and Cambodia near the Vietnam border were also sprayed. 
The Vietnam Red Cross recorded over 4.8 million deaths and 400,000 birth defects caused by the use of Agent Orange.
The US has both direct and indirect responsibility for the use of chemical weapons in Iraq over generations and must be held accountable for it. The chemical gas attack on Halabja by Saddam in 1988, which killed at least 5,000 Kurdish civilians, was carried out by the Saddam regime in the dying months of the Iran-Iraq war, during which both the UK’s Thatcher government and the Reagan White House were providing military support to the Saddam regime. The US also encouraged Saddam Hussein’s use of chemical weapons against Iran, which was the largest use of chemical weapons in history. In addition to the Kurds, at least 20,000 Iranians were killed by Saddam’s chemical weapons attacks with full US support and backing. In 1988 during Iraq's war with Iran, the United States learned through satellite imagery that Iran was about to gain a major strategic advantage by exploiting a hole in Iraqi defenses. US intelligence officials informed the Iraqi military about the location of the Iranian troops. The US authorities were fully aware that Saddam's military would attack with chemical weapons including sarin, a lethal nerve agent. The Iraqis used mustard gas and sarin prior to four major offensives in early 1988 that relied on US satellite imagery, maps, and other intelligence. These attacks changed the course of the war in Iraq's favor and made Iran come to the negotiating table. 
In addition to supporting Iraq’s use of chemical weapons against Iran, the US itself, In the most recent attacks on Iraq, used White Phosphorous, Napalm and Depleted Uranium in contravention of all conventions. According to a recent study, Fallujah now has a higher rate of cancer, leukemia and infant mortality than Hiroshima and Nagasaki in 1945. This report states that young women in Fallujah are terribly afraid of having children because an increasing number of babies are born with unimaginable grotesque birth defects. Moreover, young children in Fallujah are currently suffering from various cancers and leukemia. There is a 38-fold increase in cases of leukemia, a ten-fold increase in female breast cancer and significant increases in lymphoma and brain tumors in adults. 
The US used white phosphorus, which burns at extremely high temperatures and can burn through skin and bone if it lands on a person, on Iraq in 2004. The number of deaths and injuries due to the use of white phosphourus in Iraq is not known.
The above list is not even a full history, but some of the most notable uses. The US has consistently flouted international conventions on the use of chemical weapons. Whether we are evaluating by death toll, legacies such as birth defects and crises of public health, or environmental impacts, the US is the worst abuser of chemical weapons on the planet.
There have been efforts to outlaw chemical weapons since 1907. However, the US has either actively dodged conventions on the use of chemical weapons or, when it has seen fit to bother signing them, has simply ignored them. Moreover, it continues to increase its spending to develop more chemical weapons.
Other Western nations and chemical weapons
During World War I, Germany reintroduced chemical weapons, using chlorine gas at the second battle of Ypres. By the end of the war, all sides used mustard and chlorine gas, resulting in 85,000 people being killed and 1.2 million others injured by these toxic weapons. Between the end of WW I and 1939, there were other cases of chemical weapons usage. The UK supported the Russian forces’ use of poison gas against the Bolsheviks. Spain and France used mustard gas in Morocco. Britain used chemical weapons in Iraq "as an experiment" against Kurdish rebels seeking independence; Winston Churchill "strongly" backs the use of "poisoned gas against uncivilised tribes." Despite a brief stand off during the first year of World War II thanks to fears of reprisals from all sides, chemical weapons were again deployed in 1942. The Nazi government used Zyklon-B to exterminate “undesirable” groups.