"The first casualty of war…" is not necessarily truth, as the cliché will have us believe, but rather our ability to look for and find it.

The allegations, denials and counter-allegations have ramped up this past week in the Russia-Ukraine war, with a focus on the threat of chemical weapons and biological warfare. Official statements have been made by politicians, but they've quickly mixed with — what appear to be — unverified insinuations on social and state media.

One story claims the SARS-CoV-2 virus originated in a Ukrainian laboratory and that COVID-19 was developed as a biological weapon — an allegation that some say China, a Russian ally, would be happy to accept. But who can say for sure?

That has coincided with claims that Ukraine and its allies are developing chemical and/or biological weapons in the country and that they are planning a "dirty bomb" attack against Russia and its forces.

The US Department of State calls the Kremlin's allegations "outright lies."

"The United States does not own or operate any chemical or biological laboratories in Ukraine […]," it said in a statement published on March 9. "Russia has a track record of accusing the West of the very crimes that Russia itself is perpetrating."

So, who is telling the truth?

Who does have chemical and biological weapons, who uses them, and what are they?

Which countries own chemical and biological weapons?

It's generally said that the largest stockpiles of chemical and biological weapons were accrued during the Cold War. And the two largest players — known to have had (or still have) chemical weapons — were the United States and Soviet Russia.

But beyond that it is hard to tell.

The Arms Control Association, a political advisory body in the US, says that when the Chemical Weapons Convention (CWC) came into force in 1997, eight of its signatories declared stockpiles.

Those countries included Albania, India, Iraq, Libya, Syria, the United States, Russia and one country that remained anonymous.

Since then all but the United States have destroyed their declared stockpiles. The US still plans to destroy its chemical weapons. However Syria's assurances are regularly disputed by the Organisation for the Prohibition of Chemical Weapons (OPCW), making it difficult to know the state of the country's stockpile for sure. 

The OPCW is an international body tasked with enforcing the CWC, a convention on the prohibition of the development, production, stockpiling and use of chemical weapons and on their destruction. The CWC is the successor to the 1925 Geneva Protocol.

What's the difference between chemical and biological weapons?

Chemical weapons use chemical agents that tend to attack a person's central nervous and respiratory systems. They are usually deadly.

Nerve agents are considered to be the most lethal. They can be in liquid or gas form and inhaled or absorbed through the skin. They cause severe damage to the central nervous system and death. They include sarin, soman, and VX.

Blister agents are deployed as a gas, aerosol or liquid. They cause severe burns and blistering of the skin. If inhaled, they can affect the respiratory system. They include sulfur mustard, nitrogen mustard, lewisite and phosgene oximine.

Choking agents target the respiratory system. They include phosgene, chlorine, and chloropicrin.

Blood agents hinder the use and flow of oxygen through the body. A common blood agent is hydrogen chloride.

And there are so-called riot agents, like tear gas.

Biological weapons use microorganisms like viruses, bacteria, fungi and other toxins like ricin.

The intention is to release a living organism that can quickly spread — invisibly at first — and cause disease and death in humans, animals or plants.

They include agents such as anthrax, botulinum toxin and plague, Ebola and Lassa viruses. Aside from the basic infection caused by these weapons, there is an added effect — a large enough outbreak will cause a community's infrastructure, notably its hospitals, to fail.

Where and when have these "dirty" weapons been used?

People have used chemical and biological weapons for centuries. Archeological evidence suggests, for instance, that armies in Ancient Persia used bitumen and sulfur crystals to fight off Roman forces.

It's said that Athenian forces poisoned the water supply of a besieged city in 600BC. Peloponnesian forces used sulfur fumes against a besieged town about 100 years later.

In 1347, Mongol forces are said to have weaponized plague-infested bodies at the Black Sea port of Caffa (now Feodosiya, Ukraine). Russian forces used a similar tactic in 1710 against the people of Reval (now Tallin, Estonia). And British forces fighting in 1763 distributed blankets infested with smallpox among American Indian populations, creating an epidemic.

Then, France, which now considers itself "resolutely committed to the fight against chemical weapons," used smoke against a Berber tribe in Algeria in 1845.

Canisters of poison were dropped from balloons during the American Civil War.

In more modern warfare, forces used chlorine, phosgene and mustard gas during the First World War.

The US used the chemical defoliant Agent Orange in Vietnam. The idea was to reduce forest cover during the conflict. But Agent Orange contains dioxin which is thought to have been responsible for a high rate of birth defects and cancers for years after the war.

Weapons experts have gathered evidence that Iraq, under its now-deposed and dead leader Saddam Hussain, used chemical weapons near the end of a 1980s conflict with Iran and against its own Kurdish population in 1988. Those weapons included sarin, tabun and sulfur mustard.

Syria is said to have used chemical weapons including sarin during its ongoing Civil War in Homs, Aleppo and Damascus. But it has repeatedly denied all allegations brought by the OPCW.

Destroying chemical weapons

Countries have attempted for at least the past 400 years — starting with the Strasbourg Agreement of 1675 — to limit and ban the production and use of chemical and biological weapons and destroy them.

But they are still out there. Some even argue there are good political reasons to hold onto samples of eradicated but once-weaponized diseases like small pox.

When chemical weapons are destroyed, however, the US says it uses two methods: Incineration and neutralization. It prefers incineration but some chemical weapons can be broken down with hot water and a corrosive or "caustic" compound.

Edited by: Clare Roth