Today in History—April 24: How an Anthrax Experiment Quarantined an Island

Written by

Michele Metych

Fact-checked by

Britannica Editors

History

On this day in 1990, the longest quarantine of an island in history came to an end when the “island of death” was declared safe—after 48 years. (Guinness World Records really does have a category for everything.)

Remote and rocky Gruinard Island, off Scotland’s west coast, had been off limits since 1942, when the British government carried out secret anthrax experiments there during World War II. The goal was to weaponize the deadly bacteria against Nazi Germany.

The effort was dubbed Operation Vegetarian, a lurid pun for a plan that was both horrific and strategic. Scientists proposed infecting cattle feed—linseed cakes—with anthrax and scattering them across German pastures. Livestock would eat the infected feed and then enter the food supply, causing mass casualties.

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But they needed to test it first. So, the government bought an uninhabited island. Gruinard had been used for farming in the 18th century but was long deserted. Eighty sheep were transported over, and an anthrax bomb was triggered—remotely, of course. The sheep were dead within days. (Apparently the thinking was, if you can kill one ruminant, you can kill ’em all.)

The experiment—and those that followed—were deemed successful, and five million anthrax-laced cakes were produced.

They were never used. The Allies shifted the tide of the war with the Normandy Invasion about that time, and the plan was abandoned and the stockpile destroyed. But the island was left contaminated. Anthrax spores can persist in soil for centuries, something we didn’t know in 1942.

In 1943 a dead sheep drifted to the mainland and animals there died. The government compensated farmers but dodged disclosing the truth. Gruinard remained off limits, but it would take years for the files to be declassified.

Fun Fact

Endangered white-tailed eagles are among the birds now living on Gruinard Island.

Early decontamination attempts failed. Eventually, environmental activists stepped up a protest campaign by leaving buckets of soil from Gruinard outside government offices.

In 1986 drenching the island with a curious mix of formaldehyde and seawater and scraping and burning the top layers of soil proved successful. Tests showed that the island was anthrax-free—finally.

A defense minister traveled to the island to personally remove the last warning sign.

Today birds and rabbits nest where spores once lingered. The island looks, by all appearances, normal—which might just be the strangest part of this story.

Today in History—April 24: How an Anthrax Experiment Quarantined an Island

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