Oak Ridge: The Secret City That Built the Atomic Bomb | History Hit

Oak Ridge: The Secret City That Built the Atomic Bomb

Amy Irvine

26 Aug 2022
A movie cinema at Oak Ridge
Image Credit: United States government work; Flickr.com; https://flic.kr/p/V2Lv5D

On 6 August 1945, an American B-29 bomber named Enola Gay dropped the world’s first atomic bomb on the city of Hiroshima in Japan, killing an estimated 80,000 people. Tens of thousands more would later die of radiation exposure. Just 3 days later on 9 August 1945, another atomic bomb was dropped on Nagasaki in Japan, instantly killing a further 40,000 people and many more over time. The attacks are widely believed to have played a decisive role in convincing Japan to surrender and bringing about an end to World War Two.

Unbeknown to the rest of America – and indeed to most of the people living there – the small city of Oak Ridge in East Tennessee had played a pivotal role in this. Yet when the Japanese had attacked Pearl Harbour on 7 December 1941, the city of Oak Ridge didn’t even exist.

How did this ‘secret city’ come to be at the epicentre of the America’s plans to develop the world’s first nuclear weapons?

The Manhattan Project

In August 1939, Albert Einstein wrote to President Roosevelt warning him that the Nazis and German scientists were buying up uranium ore and might be trying to build a new and powerful bomb using nuclear technology.

In response, on 28 December 1942, President Roosevelt authorised the formation of the ‘The Manhattan Project‘ – the codename for the classified American-led effort to research, develop and build their own atomic bomb, aiming to beat the Nazis to it and use this in an effort to end the war. The project was supported by the UK and Canada, and Roosevelt appointed General Leslie Groves to be in charge.

Facilities needed to be set up in remote locations for this research and for related atomic tests to be performed.

In 1939 Franklin D Roosevelt received a letter from Albert Einstein, warning him that the Nazis might be developing nuclear weapons. America has to act fast. What follows is the creation of a secret city in the rural area of Oak Ridge, Tennessee. Around 75,000 people moved to the secret city during the World War Two, and the first atomic bomb was developed in just 28 months. Don Wildman is joined by historian, Ray Smith, to find out how it was possible, and to hear about the experiences of the people who worked at Oak Ridge, most of whom didn't know what they were creating.
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Why was Oak Ridge chosen?

Oakridge in Tennessee was one of three ‘secret cities’ chosen by Groves on 19 September 1942 to be part of the Manhattan Project, along with Los Alamos in New Mexico and Hanford/Richland in Washington state.

Thus less than a year after America entered the war, the US government started to acquire vast areas of rural farmland in order to build them. In contrast to other possible locations, Groves found that the site had virtually ideal conditions for the military’s plans. Its remote location far from the coast made the site unlikely to be bombed by the Germans or Japanese. The scarce population also made it easier to secure the cheap land – only around 1,000 families were displaced, the official reason being for the construction of a demolition range. 

The Manhattan Project needed people to work at the new plants, so nearby Knoxville with a population of 111,000 would provide labour. The sites were also close enough to established transport hubs and population centres (around 25-35 miles away) yet far enough to remain relatively under the radar. The electromagnetic, gaseous diffusion, and thermal diffusion plants in the project all required significant amounts of electricity – found nearby at the Tennessee Valley Authority hydroelectric plants at Norris Dam. The area also had good quality water and plentiful land.

US troops at a Oak Ridge pharmacy

Image Credit: United States government work; Flickr.com; https://flic.kr/p/VF5uiC

Shielded from public view, houses and other facilities were built from scratch at record speed. (By 1953, Oak Ridge had developed into a 59,000-acre site). Once built, false rumours were circulated alluding to the production of ammunition there. Clearly people suspected something significant was taking place, but at the time, no-one had ever seen or heard of a nuclear weapon. Considering America was at war, most people didn’t question things that helped the war effort.

The Oak Ridge community

Designed to house the massive facilities needed to refine radioactive material to produce fuel for atomic bombs and construct the weapons, Oak Ridge also needed to house the workers and their families. Instead of being crammed into dormitories, the leaders of The Manhattan Project felt strongly that the workers needed to feel at home and part of a ‘normal’ community. Thus individual family houses were built in what are now typical-looking suburban neighbourhoods, with winding roads, parks and other green spaces.

Oak Ridge also enabled the government to test emerging ideas, and later influenced postwar urban construction and design. Indeed Skidmore, Owings & Merrill – the architecture firm who designed the overall planning for the city, its pre-fabricated housing and even its school curriculum – is now one of the most influential in the world.

Initially Oak Ridge was conceived as a town for 13,000 people but grew to 75,000 by the war’s end, making it the fifth-largest city in Tennessee. Although these ‘secret cities’ and planned communities tried to offer their residents a happy lifestyle, familiar social problems remained, mirroring the racial segregation of that time that was considered a given by all concerned.

The architects had initially planned for ‘negro village’ at the eastern end containing similar housing to the white residents, yet as Oak Ridge grew, African-American residents were instead given ‘hutments’. These basic structures made from plywood did not fare well in the elements and lacked internal plumbing meaning residents used collective bathroom facilities. (Despite the segregation during Oak Ridge’s heyday, the city later played a prominent role in the South’s desegregation movement.)

Business activity at Oak Ridge

Image Credit: United States government work; Flickr.com; https://flic.kr/p/V2L1w6


Whilst thousands of people worked there, Oak Ridge officially did not exist during the war and couldn’t be found on any map. The site was referred to as ‘Site X’ or ‘Clinton Engineering Works’. Throughout the war, it was protected by guarded gates, and workers at the plants were sworn to secrecy.

Despite signs around Oak Ridge warning residents not to share information, it is thought that just a few hundred people in America knew about the atom bomb before it was dropped. The vast majority of the tens of thousands of residents who lived and worked at Oak Ridge didn’t know they were working on a new type of bomb, they only knew information relevant to their specific duties and that they were working towards the war effort.

On 16 July 1945, the first nuclear weapon detonation took place in the New Mexico desert, about 100 miles from Los Alamos.

After the bomb dropped

Less than a month after the initial test, the world’s first atomic bomb was dropped on Hiroshima, on 6 August 1945. News reports revealed to the people at Oak Ridge what they had been working on all along. President Truman announced the purpose of the three secret cities – Oak Ridge’s secret was out. Employees realised they had been building the most powerful weapon the world had seen.

Many residents were initially thrilled, and proud that they had worked on this new weapon that was thought would help end the war. Local papers such as the Oak Ridge Journal hailed ‘Oak Ridge Attacks Japanese’ and that it would save many lives, leading to joyous street celebrations. However, other residents were horrified their work had been part of something so destructive.

Just three days later on 9 August, another atom bomb was dropped on Nagasaki.

Keiko Ogura was just eight years old on August 6 1945 when her home city of Hiroshima was destroyed by the US in the first atomic bomb attack in history. Those who survived the a-bombs are known as hibakusha, and Keiko - as a storyteller for the Hiroshima Peace Culture Foundation - is among the most prominent. In this incredible episode, James is joined by Keiko herself to learn her riveting story of survival against all odds. Warning: The events recounted in this episode may be distressing to some listeners
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After the war

All three ‘secret cities’ continued work on nuclear weapons during the Cold War as well as broader scientific research. Today, Oak Ridge still processes enriched uranium at the Y-12 National Security Complex, but is also involved in research on renewable energy.

Many of the original buildings remain, containing signs of atomic symbols and mushroom clouds on the walls in gallows-style humour about the city’s former role. Yet whilst Oak Ridge retains its nickname as the ‘Secret City’, the city has tried to preserve a legacy about the peace that followed, rather than about the bomb itself.

Amy Irvine