Syria’s Chemical Weapons in Broader Context

World War I marked the opening act of modern chemical warfare, and that conflict’s example was followed throughout the twentieth century by regimes from Benito Mussolini’s Italy to Saddam Hussein’s Iraq and, most recently, Bashar al-Assad's Syria. The Chemical Weapons Convention, which prohibits the production and use of chemical weapons and requires the destruction of existing weapons, was opened for signatures in 1993. By the end of 1997, the year the treaty entered into force, more than 100 countries had ratified. Today, only seven countries, including Syria, remain outside the treaty. For more on Syria, see CQ’s complete coverage page

Syria’s Disputed Areas and Reported Chemical Attacks


Areas of rebel strength

Government strength


Reported chemical attacks

Mediterranean Sea

Syrian Desert



















Deir-ez Zor

Al Bukamal



April 11

Aug. 21

March 24

Dec. 23, 2012

April 19

April 13

March 19

SOURCES: Syria Needs Analysis Project, Arms Control Association, French government, Natural Earth

Major Chemical Attacks Since World War I


1915-18: Belgium

Germany launches the first major chemical weapons attack at Ypres, Belgium, during World War I. Both sides continued to use chemical weapons throughout the war.

Estimated fatalities: 6,000 at Ypres; 90,000 for all of World War I


1935: Ethiopia

Benito Mussolini's Italy drops mustard bombs and sprays mustard gas in Ethiopia during the first major use of chemical weapons since World War I.

Estimated fatalities: 15,000


1937-45: China

Japan uses a wide range of chemical agents on China in roughly 2,000 separate attacks during the course of World War II.


1962-71: Vietnam

The United States uses more than 18 million gallons of herbicides, including Agent Orange, to destroy enemy tree cover and crops during the Vietnam War. These substances are not considered chemical weapons under international law, but they have been linked to long term health problems.


1963-67: Yemen

Egypt deploys bombs and shells filled with phosgene and mustard against Yemeni royalist troops and civilians during Yemen's civil war, becoming the first Arab state to use chemical weapons.

Estimated fatalities: 1,500


1982-88: Iran

Iraq makes extensive use of chemical weapons, including mustard and the nerve agent Tabun, during its war with Iran in the 1980s.

Estimated fatalities: 45,000


1988: Iraq

Suddan Hussein deploys mustard gas and several nerve agents against Kurdish civilians in Halabja, Iraq.

Estimated fatalities: 5,000


1995: Japan

Japanese terrorists associated with the Aum Shinrikyo cult release sarin gas in five Tokyo subway trains.

Estimated fatalities: 13


2013: Syria

Bashar al-Assad's forces use chemical weapons on civilians in the outskirts of Damascus following a series of smaller-scale chemical attacks in the preceding months.

Estimated fatalities: 1,000

Countries That Have Not Adopted the Chemical Weapons Convention

In April, the foreign affairs minister of Angola confirmed his government’s intention to accede to both the Chemical Weapons Convention and the Biological and Toxin Weapons Convention.
Egyptian forces reportedly employed chemical weapons during the North Yemen Civil War in the mid-1960s. While little is publicly known of Egypt’s chemical weapons development or holdings since that time, they have asserted that they will not sign onto the Convention in light of Israel’s nuclear capabilities.
Israel is famously a non-signatory to the nuclear treaty, and has been long suspected of also developing chemical weapons. Israel’s foreign minister signed the Chemical Weapons Convention in 1993 and urged its neighbors to join them. Egypt and Syria declined to reciprocate, and disarmament progress in the region stalled. Israel has not ratified the pact.
As a signatory that hasn’t ratified the pact, Myanmar has pledged to uphold the principles of the deal, while avoiding international enforcement or verification. The ruling junta has denied several claims over the years that they have employed chemical weapons against ethnic rebels.
North Korea
North Korea is believed to possess a sizeable chemical weapons program, and is unwilling to disarm in the face of omnipresent tensions with South Korea and its allies.
South Sudan
In the 1990s, Sudan was accused of storing chemical weapons for both Iraq and Iran. The South Sudan city of Wau — while still governed by Khartoum — was reportedly home to a joint Sudanese-Iraqi chemical weapons facility. In 1999, Sudan ratified the Chemical Weapons Convention. South Sudan became an independent state in 2011 and has not yet signed onto the Convention.
Progress on a trade pact with the European Union derailed in 2004 when Syria balked over language that would prohibit them from further possession or development of weapons of mass destruction. At the time, Syria objected that Israel was subject to no such constraints.