News & Politics

Weird History: An Anthrax Lab in Chevy Chase DC

A new exhibit brings to light a WWI-era incident.

The plot involved killing horses in order to help Germany. Photograph courtesy of National Archives.

Imagine a Chevy Chase DC business and you might think of a low-key eatery or a historic movie theater. What might not come to mind: a bioweapons lab. But that’s precisely what Anton Dilger—an American surgeon born in Virginia who secretly worked for the German government—established in 1915 in his home on a leafy street in upper Northwest.

Anton Dilger. Photograph courtesy of National Archives.

The house is still there, but the crazy story isn’t well known today. We recently learned about Dilger’s dangerous home experiments from a new exhibition called “Evolution of Espionage in America.” (Most people can’t actually see the exhibit in person because it’s inside Bethesda’s National Counterintelligence and Security Center, but it’s also available online.)

As it turns out, the target of Dilger’s bioweapon efforts wasn’t people but horses. Before the US entered World War I, it sold hundreds of thousands of horses to Britain and France to help their fight against Germany. The Germans managed to convince Dilger—who was the son of a German immigrant and studying in Germany at the time—to help interfere with that effort. So with the help of his brother-­in-law Carl, Dilger returned to the US, moved into a house in Chevy Chase DC, and built a lab in the basement. The pair cooked up anthrax and glanders in a bizarrely ill-advised plot to kill horses before they could be sent abroad.

Poisoned horses in 1918. Photograph courtesy of National Archives.

The scheme involved a German agent from Baltimore who made weekly visits to Dilger’s house to collect vials, which he then handed over to other agents who would sneak onto ships loaded with horses and inject the beasts. Thousands of animals died, though almost a million eventually crossed the ocean successfully.

Army Veterinary Corps poster. Photograph courtesy of the Library of Congress.

The Germans called Dilger back to that country in 1916, but Carl kept cooking up chaos in the DC house, making explosives that were used in industrial espionage, such as the July 1916 “Black Tom” explosion that took out an entire island in New York Harbor. He finally got dropped by the Germans due to his tendency to blab about his exploits while drinking. Dilger soon headed to Mexico as part of a wacky plan to try to rekindle a border war meant to keep the US too busy to help Europe. It backfired spectacularly when British spies intercepted a German telegram encouraging Mexico to invade its northern neighbor. The British helpfully passed that on to the US, and public outrage over the revelation helped fuel America’s entrance into the war in 1917. Dilger popped up next in Madrid, where he reportedly died of Spanish flu in October 1918, less than a month before Germany surrendered.

Dilger’s house still stands—a perfectly normal-looking five-bedroom with a white picket fence and no obvious signs of its anthrax past. The owners of record, perhaps understandably, didn’t reply to our inquiries about the current state of their basement.

This article appears in the December 2022 issue of Washingtonian.

Senior editor

Andrew Beaujon joined Washingtonian in late 2014. He was previously with the Poynter Institute,, and Washington City Paper. He lives in Del Ray.