Chemical Weapons

By | Updated April 12, 2017 7:42 PM UTC

The first agreement to ban chemical weapons came in 1675. (France and the Holy Roman Empire forswore poisoned musket balls.) Three centuries and at least six international treaties later, they are still being employed, and at times it seems there's little the world can do to stop it. The nerve agent VX was used in the Feb. 13 murder of Kim Jong Nam, the half-brother of North Korean leader Kim Jong Un. In Syria, the regime of President Bashar al-Assad has repeatedly used chemical weapons against its own people, even after it agreed to surrender such munitions following a 2013 sarin gas attack that killed hundreds of civilians in a Damascus suburb. 

The Situation

After at least 80 people were killed in Syria’s Idlib province April 4, the U.S. and U.K. said evidence showed that Syrian forces used sarin gas in the attack. In response, the U.S. bombed the airfield it says was used. Sarin is a nerve agent that spreads quickly through the air, causing convulsions, coma and respiratory arrest. The U.S. strike marked a reversal for President Donald Trump, who had vowed to avoid deeper American involvement in Syria’s six-year civil war. He said his mind was changed by the brutality of the attack. A report from weapons inspectors in October concluded that the Syrian military had carried out attacks using barrel bombs filled with chlorine in 2014 and 2015, even though Assad’s forces denied it. Another study in August detected the presence of previously undeclared chemical agents at several sites, adding to concerns the regime lied about the extent of its program. Other attacks have been documented by independent groups, including a suspected mustard gas attack by Islamic State in northern Iraq in 2016. Chlorine has various industrial uses, and can also be used as a choking agent that burns the lungs. The UN Security Council adopted a resolution in 2015 that puts chlorine in the same category as other agents. Syria didn’t include chlorine as part of its disclosure of chemical weapons production and storage sites, which it surrendered after the threat of U.S.-led military action. Syria’s stash included about 1,300 metric tons of VX, sarin and mustard gas and was said by Western states to have been among the largest stocks in the world. North Korea still has one of the biggest stockpiles of chemical weapons. 

Source: OPCW, Syrian Observatory for Human Rights, Syrian Accountability Project

The Background

Despite international treaties signed before the outbreak of World War I, Germany used poison gas on the Western Front in 1915. Everyone else joined in, leaving more than 90,000 dead and a million wounded in chemical attacks by the war’s end. That memory, and the 1925 Geneva Protocol, deterred the use of chemical and still-more ghastly biological agents on the battlefields of World War II and most conflicts since then. Even so, Saddam Hussein’s chemical attacks killed 5,000 Iraqi Kurds in 1988, while a sarin attack by the Aum Shinrikyo cult killed 13 people on the Tokyo subway in 1995. And while the latest treaty, the 1997 Chemical Weapons Convention, has been signed by 192 nations, the holdouts include North Korea, Egypt and the newly independent South Sudan. Israel has signed but not ratified. The power of chemical weapons in the public imagination was illustrated by the award of the 2013 Nobel Peace Prize to the Organisation for the Prohibition of Chemical Weapons, which destroyed Syria’s declared stockpile on behalf of the UN. The U.S. and Russia are still scrapping their own chemical weapons stores, in accordance with promises they made two decades ago.

The Argument

Almost everyone agrees on the need to ban chemical munitions — even Syria finally accepted the Chemical Weapons Convention under pressure. But they can’t agree on how to do it. The assassination of North Korea's Kim in public has highlighted the danger. After the 2013 sarin attack outside Damascus, Russia and China didn't want to sanction armed force in Syria, while other UN Security Council members such as the U.S. and France argued for a military response. Russia labeled it an excuse for the U.S. to topple regimes like Assad’s, just like the invasion of Iraq in 2003. The proponents of a strike said at the time that the failure to follow through with an attack would weaken deterrence. In justifying the April bombing of the Syrian airfield, Trump cited the need to deter chemical weapons use. Intelligence officials have raised concerns that Islamic State is training its foreign fighters in the use of chlorine gas as a terror weapon that could be used when they return home.

The Reference Shelf


(An earlier version of this story corrected the date of the attack in Idlib province to April 4.)

First published Oct. 11, 2013

To contact the writer of this QuickTake:
Caroline Alexander in London at

To contact the editor responsible for this QuickTake:
Leah Harrison at