Chemical and Biological Weapons

7.1 Chemical Weapons

Chemical weapons use toxic chemical substances to kill, injure, or incapacitate adversaries. They are considered weapons of mass destruction (WMDs).

Classification by Physiological Effect

Category	Agents	Mechanism	Notorious Uses
Nerve agents	Sarin (GB), VX, Novichok, Tabun	Inhibit acetylcholinesterase → continuous nerve signal → muscle paralysis, asphyxiation	Syria (2013, 2018 — sarin); Salisbury UK poisoning (Novichok, 2018)
Blister agents (Vesicants)	Sulphur mustard (mustard gas), Lewisite	Alkylate DNA; severe blistering of skin, eyes, respiratory tract	WWI (1917); Iran-Iraq War (1980s)
Blood agents	Hydrogen cyanide (AC), Cyanogen chloride	Block cellular respiration by binding to cytochrome c oxidase	WWI; limited use in conflicts
Choking agents	Phosgene (CG), Chlorine	Damage alveoli → pulmonary oedema → asphyxiation	WWI; chlorine used by ISIS (2014)
Incapacitating agents	BZ (3-Quinuclidinyl benzilate)	Anticholinergic; confusion, hallucinations	Cold War development; not used in war

Tabun (1936) was the first organophosphate nerve agent, discovered by Gerhard Schrader (Germany) while trying to develop pesticides.

7.2 Chemical Weapons Convention (CWC)

CWC is an international arms control treaty that outlaws the production, stockpiling, and use of chemical weapons and requires their destruction.

Key Parameter	Detail
Adopted	1993 (Paris)
Entry into force	April 29, 1997
Signatories	193 member states (only 4 non-signatories: Israel, Egypt, North Korea, South Sudan)
Implementing body	OPCW (Organisation for the Prohibition of Chemical Weapons), The Hague, Netherlands
Nobel Peace Prize	OPCW awarded Nobel Peace Prize in 2013
India's status	India ratified CWC in 1996; declared and destroyed all its chemical weapons stockpiles (completed 1997)
Most significant destruction	USA completed destruction of all declared chemical weapons on July 7, 2023 — global milestone

OPCW Mandate

• Oversees the global ban on chemical weapons
• Inspects chemical industry to prevent misuse
• Provides assistance to countries threatened by chemical attack
• Investigates alleged use (Syria investigations)

Syrian Chemical Weapons Programme: Syria acceded to CWC in September 2013 after international pressure following a sarin attack in Ghouta killing 1,400+. However, OPCW investigations found Syria continued chemical weapon use (chlorine barrel bombs, sarin attacks 2017–2018). Syria was suspended from OPCW in April 2021.

7.3 Biological Weapons

Biological weapons use living organisms (bacteria, viruses, fungi, toxins) to cause harm. They are classified as weapons of mass destruction.

Types of Biological Agents

Category	Agents	Why Dangerous
Bacteria	Anthrax (B. anthracis), Plague (Y. pestis), Tularemia	Highly lethal; anthrax spores survive decades
Viruses	Smallpox (Variola), Ebola, Marburg	Highly contagious; limited treatment
Toxins	Botulinum toxin (most toxic substance known), Ricin, Abrin	Nanogram quantities lethal
Fungi	Yellow rain (trichothecene mycotoxins)	Alleged use in Southeast Asia (1970s)

Anthrax (Bacillus anthracis): Bacterial spores can be aerosolised for inhalation anthrax (80–90% mortality if untreated). The 2001 US anthrax letters caused 5 deaths and 17 infections. It is treatable with antibiotics (ciprofloxacin) if caught early.

7.4 Biological Weapons Convention (BWC)

BWC was the first international agreement to prohibit the development, production, and stockpiling of an entire category of WMDs.

Key Parameter	Detail
Adopted	April 10, 1972 (Washington, London, Moscow)
Entry into force	March 26, 1975
Signatories	183 states parties
India's ratification	1974
Key weakness	No verification mechanism (unlike CWC's OPCW) — nations must self-declare compliance; review conferences every 5 years

BWC Weakness vs CWC Strength

• CWC: Has OPCW with intrusive inspection rights, chemical industry monitoring, and international investigation capacity
• BWC: No equivalent international monitoring body; relies on state declarations; difficult to verify because civilian biotech labs can potentially be repurposed

COVID-19 origins controversy (lab leak hypothesis): The BWC framework has been stressed by concerns about dual-use research — research that advances medicine but could theoretically be weaponised. Gain-of-function research (making pathogens more transmissible/virulent) is controversial.

---