An Historian Just Discovered A Secret Memo Detailing Britain’s Plans To Use Chemical Weapons During The War Of 1812

Published July 27, 2026

The memo shows that Royal Navy commander Thomas Cochrane hatched a daring scheme to pack ships with sulfur, send them into the heart of the American fleet, and then set them ablaze.

Planned Chemical Attack In War Of 1812

Public DomainA newly-found memo details a British plan to release toxic fumes against U.S. fleets during the War of 1812.

A memo that was recently found in the National Archives of Scotland revealed that Britain had planned a chemical weapons attack on American ships during the War of 1812.

The 23-page document states that Royal Navy commander Thomas Cochrane came up with the idea to deploy toxic sulfur fumes against fleets of U.S. ships. If the plan had come to fruition, it may have been the first chemical weapons attack in history.

The British Plan To Carry Out A Chemical Weapons Attack Against American Ships During The War Of 1812

The document was discovered by historian Peter Moore, who is working on a biography of Cochrane. The memo was written by Cochrane’s secretary in 1844, and displays handwritten annotations by Cochrane himself.

Thomas Cochrane

Public DomainThe plan was devised by Royal Navy commander Thomas Cochrane.

Cochrane made his name during the Napoleonic Wars due to his bold naval operations and his skill at developing experimental weapons.

During the War of 1812, he devised a plan to load British ships with sulfur and various flammable materials, then send them into the heart of an American fleet and set them ablaze, resulting in toxic fumes that would smother and cripple the enemy.

The fumes were meant to drive away or debilitate enemy forces, and Cochrane believed that this tactic would help the British overtake forts that would have otherwise been challenging to capture.

Cochrane thought of the plan after visiting Sicily in 1811 and noticing the toxic gases that resulted from sulfur mining. He presented the plan to a secret group of military officials, including the Duke of York and the Prince Regent, who later became King George IV.

War Of 1812

Public DomainBritish forces managed to capture Washington, D.C. and burn the White House, but suffered major losses in New Orleans.

The committee was highly supportive of the plan, but was concerned that once they used this approach, enemy forces would use it back on them. As a result, Cochrane was told to keep the mission secret.

When Cochrane’s uncle, Vice-Admiral Alexander Cochrane, was appointed commander-in-chief of the British navy operating in North America, Thomas Cochrane was chosen to be his flag captain and was expected to command the HMS Tonnant.

In the memo, Cochrane indicated that his uncle intended to call for the chemical attack if necessary, although the exact target was not identified. According to the document, New York, Baltimore, or New Orleans might have been the targets — had they gone through with it.

How This Memo Contributes To Our Understanding Of Military History

In the end, the plan fell apart before Cochrane could leave for his mission. In 1814, he was convicted in a London Stock Exchange fraud scheme in which a hoax was spread that Napoleon died, leading to a sharp rise in share prices.

Thomas Cochrane Cartoon

Public DomainA political cartoon showing Cochrane as both a naval commander and a disgraced civilian after his fraud conviction.

After his conviction, Cochrane was kicked out of parliament and removed from naval service in North America. Still, Cochrane was influential in Chile and Brazil, helping to organize their revolutionary navies during their wars for independence in the 1820s. In 1832, Cochrane was pardoned in Britain, and he died in 1860 with the rank of Admiral of the Red and honorary Rear-Admiral of the United Kingdom.

Although Britain managed to capture Washington, D.C. and burn the White House during the War of 1812, they faced a major defeat in New Orleans before the war ended in early 1815. Cochrane apparently believed that the war would have had a different outcome if his chemical weapons plans had been carried out.

If chemical weapons had been used, this would have perhaps been the first attack of its kind in history. However, this needs qualification, as toxic smoke had been deployed before the 19th century.

A study published by archaeologist Simon James in the American Journal of Archaeology details how, circa 256 C.E., in the ancient city of Dura-Europos, Sasanian Persian forces burned sulfur in a siege tunnel to incapacitate Roman soldiers.

While Cochrane’s plan may not have been humanity’s first deployment of toxic gas during combat, it would have been the first naval gas attack on a large scale in the modern era — but he simply never got the chance to make history.


After reading about the memo that details Britain’s planned chemical attack on the U.S. during the War of 1812, learn about Jean Lafitte, the French pirate king who helped defend New Orleans in the War of 1812. Then, discover the story of Edgewood Arsenal, the U.S. military’s top-secret human experiment program during the Cold War.

All That's Interesting Logo
Our Editorial Standards

All That's Interesting is a U.S.-based digital publisher that employs subject-level experts to produce our articles. Each article is written by a staff member or a highly-vetted freelancer, and is reviewed by at least one editor. For licensing and permission inquiries, visit Wright's Media.

Become a member to help support our work and enjoy our site ad-free.

author
Ella Spitz
author
Based in Brooklyn, Ella Spitz is an editorial fellow at All That’s Interesting. She previously worked as an associate editor and staff writer at The Indypendent, and as a reporting intern for the Portland Press Herald. Ella graduated from Wesleyan University with a B.A. in English and a minor in religion.
editor
John Kuroski
editor
Based in Brooklyn, New York, John Kuroski is the editorial director of All That's Interesting. He graduated from New York University with a degree in history, earning a place in the Phi Alpha Theta honor society for history students. An editor at All That's Interesting since 2015, his areas of expertise include modern American history and the ancient Near East. In an editing career spanning 17 years, he previously served as managing editor of Elmore Magazine in New York City for seven years.
Citation copied
COPY
Cite This Article
Spitz, Ella. "An Historian Just Discovered A Secret Memo Detailing Britain’s Plans To Use Chemical Weapons During The War Of 1812." AllThatsInteresting.com, July 27, 2026, https://allthatsinteresting.com/war-of-1812-chemical-weapons-attack. Accessed July 27, 2026.