World War I: The use of poison gas in World War I escalates when chlorine gas is released as a chemical weapon in the Second Battle of Ypres.

World War I

1914–1918 global conflict

World War I or the First World War, also known as the Great War, was a global conflict between two coalitions: the Allies and the Central Powers. Main areas of conflict included Europe and the Middle East, as well as parts of Africa and the Asia-Pacific. There were important…

Chemical weapons in World War I

The use of toxic chemicals as weapons dates back thousands of years, but the first large-scale use of chemical weapons was during World War I. They were primarily used to demoralize, injure, and kill entrenched defenders, against whom the indiscriminate and generally very…

Chlorine

Chemical element with atomic number 17 (Cl)

Chlorine is a chemical element; it has symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature.…

Chemical warfare

Using poison gas or other toxins in war

Chemical warfare (CW) involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from nuclear warfare, biological warfare and radiological warfare, which together make up CBRN, the military acronym for chemical, biological,…

Second Battle of Ypres

Battle of the First World War

The Second Battle of Ypres was fought from 22 April – 25 May 1915, during the First World War, for control of the tactically-important high ground to the east and the south of the Flemish town of Ypres, in western Belgium. The First Battle of Ypres had been fought the previous…