The Manhattan Project Was Full Of Soviet Spies

The Manhattan Project Was Full Of Soviet Spies

Nuclear secrets are the most secret secrets of all, the news has recently reminded us. And the Manhattan Project—the quest to create the first atomic bomb—was super secret, with even plenty of people connected to it not knowing what it really was. And yet the project was infiltrated by Soviet informants. Multiple Soviet informants. 

Spy number one: Theodore Hall, born Theordore Holtzberg, because he was the son of Russian-born Barnett Holtzberg, who’d fled Russia to avoid persecution. Hall graduated high school at 14, graduated Harvard at 18, and was recruited to the Manhattan Project at 19. His Soviet codename was Mlad, or “Youngster.” 

Hall became a spy through his college roommate, Saville Sax (whose codename was “Oldster,” despite just being one year Hall’s senior). Sax’s parents were both Russian, and his mother was in a secret Communist group. Hall asked him to arrange a meeting with the KGB, and Hall showed up at this very first meeting with nuclear research documents. He went on passing along info throughout his time with the project, and though the FBI opened an investigation on him in 1951, they didn’t arrest him. The FBI released the evidence they had on him in 1995, and he publicly confessed in 1998, receiving no punishment. 

Another spy at the project, Klaus Fuchs actually was tried and convicted in 1950. Fuchs came from Germany to Britain as a refugee in 1933. Britain stuck him in an internment camp in Canada. He came back to Britain, became a nuclear scientist, got transferred to Columbia University, then joined the Manhattan Project. 

Fuchs too approached the Soviets to become a spy, and the info he passed along was serious stuff: He taught the Soviets how to process uranium. The British discovered he was a spy and sentenced him to 14 years. He was guilty of espionage but not treason—remember, the Soviets were working with the US and the UK at the tail end of World War II.

Hall and Fuchs never worked together, and during their time on the Project, neither knew the other was a spy. They were just two of the Soviet spies on the Project; there were others as well. There was David Greenglass (brother to Ethel Rosenberg, who was famously executed for espionage, along with her husband), and then there was Oscar Seborer, who was only confirmed as a spy in 2019. Today, no reputable source on the Manhattan Project definitively states how many spies infiltrated it. We have to assume even more may have, undetected. 

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