Chemical warfare in the context of "Chemical weapon"

The First Sacred War, or Cirraean War, was fought between the Amphictyonic League of Delphi and the city of Kirrha. At the beginning of the 6th century BC, the Pylaeo-Delphic Amphictyony, controlled by the Thessalians, attempted to take hold of the Sacred Land (or Kirrhaean Plain) of Apollo, resulting in this war. The conflict arose due to Kirrha's frequent robbery and mistreatment of pilgrims going to Delphi and their encroachments upon Delphic land. The war, which culminated with the defeat and destruction of Kirrha, is notable for the use of chemical warfare at the Siege of Kirrha, in the form of hellebore being used to poison the city's water supply. The war's end was marked by the organization of the first Pythian Games.

The Defense Threat Reduction Agency (DTRA) is both a defense agency and a combat support agency within the United States Department of Defense (DoD) for countering weapons of mass destruction (WMD; chemical, biological, radiological, nuclear, and high explosives) and supporting the nuclear enterprise. Its stated mission is to provide "cross-cutting solutions to enable the Department of Defense, the United States Government, and international partners to Deter strategic attack against the United States and its allies; Prevent, reduce, and counter WMD and emerging threats; and Prevail against WMD-armed adversaries in crisis and conflict." DTRA is headquartered in Fort Belvoir, Virginia. The DTRA mission, organization and management, responsibilities and functions, relationships, authorities, and administration are defined in DoD Directive 5105.62, Defense Threat Reduction Agency (DTRA).

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 slow-moving or static nature of gas clouds would be most effective. The types of weapons employed ranged from disabling chemicals, such as tear gas, to lethal agents like phosgene, chlorine, and mustard gas. These chemical weapons caused medical problems. This chemical warfare was a major component of the first global war and first total war of the 20th century. Gas attack left a strong psychological impact, and estimates go up to about 90,000 fatalities and a total of about 1.3 million casualties. However, this would amount to only 3–3.5% of overall casualties, and gas was unlike most other weapons of the period because it was possible to develop countermeasures, such as gas masks. In the later stages of the war, as the use of gas increased, its overall effectiveness diminished. The widespread use of these agents of chemical warfare, and wartime advances in the composition of high explosives, gave rise to an occasionally expressed view of World War I as "the chemist's war" and also the era where weapons of mass destruction were created.

The use of poison gas by all major belligerents throughout World War I constituted war crimes as its use violated the 1899 Hague Declaration Concerning Asphyxiating Gases and the 1907 Hague Convention on Land Warfare, which prohibited the use of "poison or poisoned weapons" in warfare. Chemical weapons in World War II saw widespread use by Germany during the Holocaust and by Japan against China. Battlefield use against Western Allies was prevented by deterrence.

Water supply terrorism involves acts of sabotage to a water supply system, through chemical or biological warfare or infrastructural sabotage. Throughout military history and the history of terrorism, water supply attacks have been perpetrated by political groups, intending to scare, cause death, or drought.

Bioterrorism is terrorism involving the intentional release or dissemination of biological agents. These agents include bacteria, viruses, insects, fungi, and/or their toxins, and may be in a naturally occurring or a human-modified form, in much the same way as in biological warfare. Further, modern agribusiness is vulnerable to anti-agricultural attacks by terrorists, and such attacks can seriously damage economy as well as consumer confidence. The latter destructive activity is called agrobioterrorism and is a subtype of agro-terrorism.

The Russian Federation is known to possess or have possessed three types of weapons of mass destruction: nuclear weapons, biological weapons, and chemical weapons. It is one of the five nuclear-weapon states recognized under the Treaty on the Non-Proliferation of Nuclear Weapons and one of the four countries wielding a nuclear triad. Russia has been alleged to violate the Biological Weapons Convention and Chemical Weapons Convention.

As of 2025, Russia's triad of deployed strategic nuclear weapons includes approximately 1,254 intercontinental ballistic missiles, 992 submarine-launched ballistic missiles, and 586 cruise missiles or bombs for delivery by Tupolev Tu-160 and Tu-95 bombers. It also possesses the world's largest arsenal of tactical nuclear weapons, approximately 1,500. Since 2022, Russia has provided tactical nuclear weapons to Belarus.

The Campaign for Nuclear Disarmament (CND) is an organisation that advocates unilateral nuclear disarmament by the United Kingdom, international nuclear disarmament and tighter international arms regulation through agreements such as the Nuclear Non-Proliferation Treaty. It opposes military action that may result in the use of nuclear, chemical or biological weapons, and the building of nuclear power stations in the UK.

CND began in November 1957 when a committee was formed, including Canon John Collins as chairman, Bertrand Russell as president and Peggy Duff as organising secretary. The committee organised CND's first public meeting at Methodist Central Hall, Westminster, on 17 February 1958. Since then, CND has periodically been at the forefront of the peace movement in the UK. It claims to be Europe's largest single-issue peace campaign. Between 1958 and 1965 it organised the Aldermaston March, which was held over the Easter weekend from the Atomic Weapons Establishment near Aldermaston to Trafalgar Square, London.

A weapon of mass destruction (WMD) is a biological, chemical, radiological, nuclear, or any other weapon that can kill or significantly harm many people or cause great damage to artificial structures (e.g., buildings), natural structures (e.g., mountains), or the biosphere. The scope and usage of the term has evolved and been disputed, often signifying more politically than technically. Originally coined in reference to aerial bombing with chemical explosives during World War II, it has later come to refer to large-scale weaponry of warfare-related technologies, such as biological, chemical, radiological, or nuclear warfare.

The histories of biological and chemical warfare date from antiquity to the modern period, with toxic gases used on a vast scale in World War I. In the 20th century, nuclear weapons were first developed, and were used in war twice, in the atomic bombings of Hiroshima and Nagasaki. Biotechnology allowed for the enhancement of pathogens as weapons, and advanced chemical weapons such as nerve agents were developed. Radiological weapons have never been used or mass-produced.