Chemical weapons in the form of poisoned arrows have existed since the Stone Age, but gaseous chemical weapons weren’t utilized until WWI. The hideous scourges of Phosgene and Mustard gas required a throughly modern understanding of chemistry and industrial processes. But I want to know if there’s another way to produce aerosolized chemical weapons.

Is there any agent, whether chemical or even biological that could be developed by preindustrial means in order to be used to kill or incapacitate in confined areas? It would be pumped into tunnels in order to flush out undermining foes or against enemies in fortified positions.

  • 5
    $\begingroup$ Biological weapons were used in siege warfare in the form of rotting corpses. $\endgroup$
    – Gene
    Jan 26, 2020 at 7:20
  • $\begingroup$ Pre industrial and pumping? $\endgroup$
    – L.Dutch
    Jan 26, 2020 at 7:27
  • 3
    $\begingroup$ Brimstone appears in the bible, you can use it as medicine or genocide. $\endgroup$
    – user6760
    Jan 26, 2020 at 7:49
  • $\begingroup$ @Gene very true, corpses are also good for contaminating water supplies $\endgroup$ Jan 26, 2020 at 8:12
  • $\begingroup$ @L.Dutch -Reinstate Monica Bellows pump air and are throughly Pre industrial $\endgroup$ Jan 26, 2020 at 8:13

3 Answers 3


What is a poison gas? Technically, you'd speak about "Airborne toxic agent" or "airborne chemical weapon", as gas is an aggregate and most chemical agents that are not gas-shaped are powders or droplets carried by air. Now, what is there?

Caustic smoke

One of the most simple airborne chemicals is smoke. Thick smoke from burning wet wood or unpacked, loose gunpowder can be used to block sight and reduce the ability to fight in it, demanding the use of wet-cloth 'gasmasks' to be able to fight for more than a short time in it.

To increase the effectiveness, adding more sulphur into the mix would be a great way: the produced SO, SO2 and SO3 turn into acid in the lungs of victims. Sulphur was used in such capacity at least as a secondary effect historically when using flaming siege ammunition made from bags of tar and sulphur. Such ammunition also is harder to douse with water, as it burns hotter.

Another agent that, when burned, creates very bright light as well as thick and caustic fumes are derived from phosphor. White Phosphor was first isolated in 1669, which is pre-industrial post-medieval. It ise feasable that it could be isolated earlier, as the isolation process taken was simply cooking urine.

reality check

In the tunnel battles under Vienna during the siege of the Ottomans in 1529, smoke was used en-masse to try to drive out siege and countersiege tunnling by removing visibility, displacing oxygen and making it hell down there.

Simple Gases

Arsine (AsH3) is a flameable and pyrophoric... and highly toxic. It could be generated on the battlefield by pouring a strong acid over a dry powder mixed of Arsene-III-oxide (natural occuring) and Zink powder (refinement of Zinc is known since antics). The main problem with the use would be the high flameability, though in tunnels this would be actually a huge benefit: if someone brings a torch to light it, they also blow out the tunnel, killing combatants.

Similarilay, Prussic Acid, aka Hydrogen Cyanide, can be created by letting ammonia gas blow through glowing coal. Ammonia Gas can be generated by mixing ammonia salts with quicklime.

The Ammonia gas also could be just released or burned to generate Nitrogen oxides; both are pulmonary chemical weapons.

  • $\begingroup$ This is exactly what I was looking for $\endgroup$ Jan 26, 2020 at 21:54
  • $\begingroup$ Even a relatively clean-burning fire will still render the air unbreathable in short order due to incomplete combustion producing CO, as well as the potential for oxygen deprivation in short order in anything resembling a confined space $\endgroup$
    – Shalvenay
    Jan 27, 2020 at 4:14
  • $\begingroup$ @Shalvenay It depends on the size of the flame. They used candles in tunnels somewhat safely. $\endgroup$
    – Trish
    Jan 27, 2020 at 11:02


In tunnels smoke can be deadly. If you burn sulphur it can be even worse. Seal one end off and use bellows to pump the smoke into the confined area.

Easily done in any era.

  • $\begingroup$ can also be used in a field of battle, if your enemy's in tight formation and weather is fine $\endgroup$ Jan 26, 2020 at 13:35
  • 1
    $\begingroup$ Also depends on what you're burning ... poison ivy, for instance... $\endgroup$ Jan 27, 2020 at 6:05

Poisonous or noxious gases have sometimes been used in warfare as early as antiquity.

The remains of 20 dead Roman soldiers in a tunnel in the fortifications of Dura-Europos, Syria indicate they were suffocated with poison gas by attacking Persians in siege warfare about AD 256.



This battle may have been mentioned by Adrienne Mayor in her book Greek Fire, Poison arrows, and Scorpion Bombs, 2003, which sounds like it may have other examples of ancient use of poison gas.


"There was a lot of chemical warfare [in the ancient world]," Mayor, who was not involved in the study, told LiveScience. "Few people are aware of how much there is documented in the ancient historians about this."

One of the earliest examples, Mayor said, was a battle in 189 B.C., when Greeks burnt chicken feathers and used bellows to blow the smoke into Roman invaders' siege tunnels. Petrochemical fires were a common tool in the Middle East, where flammable naphtha and oily bitumen were easy to find. Ancient militaries were endlessly creative: When Alexander the Great attacked the Phoenician city of Tyre in the fourth century B.C., Phoenician defenders had a surprise waiting for him.

"They heated fine grains of sand in shields, heated it until it was red-hot, and then catapulted it down onto Alexander's army," Mayor said. "These tiny pieces of red-hot sand went right under their armor and a couple inches into their skin, burning them."

So the idea that the Persians had learned how to make toxic smoke is, "totally plausible," Mayor said.



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