Many nations continue to research and/or stockpile chemical weapon agents despite numerous efforts to reduce or eliminate them. Most states have joined the Chemical Weapons Convention (CWC), which required the destruction of all chemical weapons by 2012. Twelve nations have declared chemical weapons production facilities and six nations have declared stockpiles of chemical weapons. All of the declared production facilities have been destroyed or converted for civilian use after the treaty went into force.

CWC states with declared stockpiles Of the 193 nations that have signed the CWC, states listed below have also declared stockpiles and agreed to monitored disposal and verification. Iraq Japan Libya Russia Syria United States In some cases, chemical weapons were used in conflict such as the Iran–Iraq War and Syrian civil war. Both military targets and civilian populations have been affected.

Details by state Albania

Albania, as a party of the Chemical Weapons Convention, declared a stockpile of 16 tons of chemical weapons in 2007. On July 11, 2007, with the help of the U.S. government's Nunn–Lugar Cooperative Threat Reduction program, the Ministry of Defence announced the successful destruction of the entire stockpile.

Angola Angola has been accused of using chemical weapons in its civil war.

China According to the testimony from Assistant Secretary of State for Intelligence and Research Carl W. Ford before the Senate Committee on Foreign Relations, it is very probable that China has an advanced chemical warfare program. This includes research and development, production, and weaponization capabilities. The United States is concerned by China's contact and willingness to share chemical weapons expertise with other states of proliferating concern, including Syria and Iran. Chinese government did declare that they had a small arsenal of chemical weapons in the past but that it was destroyed before the ratifying convention. They declared only two former chemical production facilities that may have produced mustard gas and Lewisite.

Cuba

According to a United Nations finding, that cited suspicious residue affecting plant and animal life during the Cuban intervention in Angola, sarin and VX was used against Angolan militants by the Cuban Army.

Egypt Egypt did not sign the Chemical Weapons Convention and has been appearing on various lists as having an offensive chemical weapons capability and is thought to have production facilities for sarin, VX, mustard gas and phosgene. Before the Egypt–Israel peace treaty of 1979, the country played a pivotal role exporting chemical weapons and related technologies to other Arab countries. It is possible that Egypt may still have limited stockpiles of chemical bombs, rockets and shells.

There are numerous reasons for this belief: Egypt is known to have used mustard gas in the Yemen civil war from 1963 to 1967. In the 1970s, Syria got their first chemical weapons from Egypt during the Yom Kippur War, but they were never used in this conflict."Country profile: Syria – chemical weapons". NTI Research Library. Nuclear Threat Initiative. In the 1980s, Egypt supplied Iraq with mustard gas and nerve agents as well as related production and deployment technology.

In testimony before the Subcommittee on Seapower: Strategic and Critical Materials in 1991, US Navy Rear Admiral Thomas Brooks cited this evidence in identifying Egypt as a "probable" country to have chemical weapons.

Recent analyses are more careful estimating the current status of a chemical weapons program in Egypt. Only one facility has been identified as "likely involved" in the offensive activities. Although the offensive program may be still in existence, it does not seem that Egypt has a considerable stockpile of operational weapons.

Ethiopia In 1991 Rear Admiral Thomas Brooks identified Ethiopia before the Congress as a "probability" to have chemical weapons possession. Ethiopia did ratify the CWC in 1996 and did not declare an offensive chemical weapons program. Since then, no evidence has been presented to contradict this statement.

India On January 14, 1993, India became one of the original nations to sign the CWC. India declared its stock of chemical weapons in June 1997 which included 1,044 tonnes of sulfur mustard in its possession.

In 2005, of the six nations that declared stockpiles of chemical weapons, India was the only one to meet their deadline for the destruction of chemical weapons and inspection of its facilities by the OPCW. By the end of 2006, India had destroyed more than 75 percent of its chemical weapons and material stockpile. They were granted an extension to destroy the remainder by April 2009. On May 14, 2009, India informed the United Nations that it had completely destroyed its stockpile of chemical weapons.

Iran Near the end of the Iran–Iraq War, Iran was suspected to have made limited use of chemical weapons in response to multiple chemical attacks by Iraq. The delivery vehicles Iran supposedly had in their possession included artillery shells, mortars, rockets and aerial bombs.

According to the Center for Strategic and International Studies, a Washington D.C.–based think tank, Iran currently has at least two major facilities for the research and production of chemical weapons. Iran began their production of nerve agents no later than 1994. The accuracy of these claims has not been verified.

Iran signed the Chemical Weapons Convention on January 13, 1993, and ratified it on November 3, 1997. They deny allegations of having a clandestine CW program in violation of CWC. In the official declaration submitted to OPCW, the Iranian government admitted that it produced mustard gas in 1980s but ceased the offensive program and destroyed stockpiles of operational weapons after the end of the war with Iraq.

Iraq

Well before Operation Desert Storm or the U.N. inspections that followed it, Iraq had already begun to build chemical weapons. After launching a research effort in the 1970s, Iraq was able to use chemical weapons in their war against Iran and to kill large numbers of their own Kurdish population in the 1980s. On June 28, 1987, in Sardasht, during two separate attacks on four residential areas, an estimated as 10 civilians were killed and 650 civilians injured. Iraq used an excessive amount of chemical weapons during Iran–Iraq War. Kurdish people were victims of chemical weapons. Iraq used mustard gas in an attack against Kurdish people on March 16, 1988, during the Halabja chemical attack. The attack killed between 3,200 and 5,000 people and injured 7,000 to 10,000 more, most of them civilians. During Iraqi chemical attacks against Iran, many Iranian military forces were killed by nerve agents. At the time, the attacks were actively supported by the United States.

During the first Gulf War, there were fears that Iraq would launch chemical-tipped missiles at its neighbors, particularly Israel, but Iraq refrained for fear of U.S. retaliation. During Operation Iraqi Freedom, coalition troops again feared they might be hit with chemical weapons, though this did not happen.

In 1991, as part of the 1991 Gulf War ceasefire agreement, the United Nations passed Resolution 687 that established the Special Commission (UNSCOM). The UNSCOM was charged with the task of destroying, removing or rendering harmless "all chemical and biological weapons and all stocks of agents and all related subsystems and components and all research, development, support and manufacturing facilities."

By the time UNSCOM left Iraq in December 1998, it had destroyed a large portion of Iraq's chemical weapon potential. UNSCOM had overseen the destruction or incapacitation of more than 88,000 filled or unfilled chemical munitions, over 600 tons of weaponized or bulk chemical agents, 4,000 tons of precursor chemicals, 980 pieces of key production equipment and 300 pieces of analytical equipment. Notwithstanding these achievements, the uncertainties regarding Iraq's possession of chemical weapons, their precursors and munitions remain.

The Organisation for the Prohibition of Chemical Weapons that oversee destruction measures, announced that "The government of Iraq has deposited their accession to the Chemical Weapons Convention with the Secretary General of the United Nations and within 30 days, on 12 February 2009, will become the 186th State to the Convention". Iraq also declared stockpiles of CW. Because of their recent accession, will be the only State Party exempted from the destruction time-line. On September 7, 2011, Hoshyar Zebari entered the OPCW headquarters, becoming the first Iraqi Foreign Minister to officially visit since the country joined the CWC.

Israel In 2015, Israel signed but did not ratify the Chemical Weapons Convention. According to the Russian Federation Foreign Intelligence Service, Israel has significant stores of chemical weapons they manufactured themselves. They have a highly developed chemical and petrochemical industry, skilled specialists and stocks of source material. They are capable of producing several nerve, blister and incapacitating weapons. A 2005 report from the Swedish Defence Research Agency concluded that Israel was probably not actively producing "traditional" chemical weapons but might have a functional stockpile of previously produced material. Assessment of Israeli chemical weapons capabilities were redacted from declassified U.S. documents.

Although Israel did sign the CWC, it has not ratified the treaty and therefore is not officially bound by its provisions. Beliefs are that Israel has a significant stockpile of chemical weapons, likely to be the most abundant in the Middle-East according to the Russian Foreign Intelligence Service. A 1983 CIA report stated that Israel, after "finding itself surrounded by front-line Arab states with budding chemical weapon capabilities, became increasingly conscious of its vulnerability to chemical attack ... undertook a program of chemical warfare preparations in both offensive and protective areas ... In late 1982, a probable CW nerve agent production facility and a storage facility were identified at the Dimona Sensitive Storage Area in the Negev Desert. Other CW agent production is believed to exist within a well-developed Israeli chemical industry."

In 1974, in a hearing before the U.S. Senate Armed Services Committee, General Almquist stated that Israel had an offensive chemical weapons capability.

In 1992, El Al Flight 1862 bound for Tel Aviv crashed outside Amsterdam. During the course of the crash investigation, fifty gallons of dimethyl methylphosphonate was found in the plane's cargo. Dimethyl methylphosphonate is a CWC schedule 2 chemical that can be used in the production of the nerve agent sarin. The dimethyl methylphosphonate was bound for the Israel Institute for Biological Research in Ness Ziona, a top-secret military installation outside Tel Aviv. The facility was also responsible for producing the poison used in a September 1997 assassination attempt on a leader of the Palestinian militant organization Hamas (Khaled Mashal). According to Israeli officials, the substance was destined for defensive research purposes, to test filters for gas masks. This shipment came from a US chemical plant to the IIBR under a US Department of Commerce license.

The 1993 the U.S. Congress Office of Technology Assessment WMD proliferation assessment recorded Israel as a country known to have undeclared offensive chemical warfare capabilities.

In October 1998, the London Sunday Times reported that Israeli F-16 fighters were equipped to carry chemical weapons and that their crews have been trained on the use of such weapons.

Japan