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An atomic bomb test detonation on the Marshall Islands in 1946

5 accidental consequences of the US nuclear bomb tests

The United States’ nuclear bomb testing regime had widespread effects detectable throughout the world. Some of these effects persist to this day… 

Image: Atomic bombs were detonated as part of Operation Crossroads at Bikini Atoll in the Marshall Islands. The Baker Test (Above) took place on 25th July 1946 |

It’s undeniable that the United States’ Manhattan Project changed the course of history. Everyone knows the story of how J. Robert Oppenheimer and his team of scientists developed the atomic bomb, and how the strikes on Hiroshima and Nagasaki ended World War II.

However, it’s not so well known that the United States’ nuclear bomb testing regime, both during World War II and afterwards, had widespread but subtle effects detectible across the country and throughout the world. Some of these effects even persist to this day.

About nuclear fallout

Many unintended effects of the US nuclear bomb tests related to the spread of radioactive fallout.

Since US nuclear testing was secret, it was not done near densely populated areas. Yet the nuclear testing sites were not far away enough from human habitations to prevent nuclear fallout from reaching them.

In fact, fallout can spread immense distances on the wind. Crucially, winds in the US tend to blow eastward, so fallout from testing sites in places in America’s west, like Nevada, would blow east across populated areas.

1. X-ray and film contamination in Indiana and Iowa

Military personnel observe an atomic bomb test in Nevada
Image: Military personnel observe a 21 kiloton atomic test in Nevada on 1st November 1951 as part of Operation Buster-Jangle |

In 1945, the Kodak company found that the ‘Trinity’ nuclear bomb test had produced fallout that spread as far as a warehouse in Indiana. How did Kodak find out about this? They began to receive complaints of fogged spots on their photographic and X-ray film.

Kodak scientist Julian H. Webb looked into the matter. He found that fallout from Trinity had drifted west on the wind, contaminated Indiana’s Wabash River, and thereby reached a paper mill. The strawboard packaging produced in the mill at the time became radioactive, and that radioactivity was damaging Kodak’s film.

The contamination at the mill occurred on 6th August 1945, less than a month after Trinity was detonated on 16th July 1945.

2. Contaminated milk in the 1940s, 50s, and 60s

The spread of nuclear fallout in the air westwards across the US from testing sites in Nevada and the Trinity site in New Mexico meant that grass and plants became contaminated. When dairy cows ate that grass, the radioactive iodine-131 in it passed into their milk. And when children drank the milk, they drank the radioactive particles too.

Therefore, the US government’s own website on cancer warns that children who drank a lot of milk during these years might experience an increased risk of thyroid cancer throughout their lives.

The US government also provides a calculator that people can use to calculate their exposure to iodine-131 based on where they live and their milk consumption.

3. Radioactive honey in the USA today

In 2021, a study published in Nature Communications reported that radioactive caesium particles from nuclear bomb tests in the 1950s and 60s were still being found in honey in the USA. These caesium particles have a half-life of 30.2 years – meaning that although their radioactivity had decreased, it was by no means gone.

The scientists found that plants were taking up caesium because they were mistaking it for potassium, an essential plant nutrient. And when bees produced honey from these plants'

nectar, the caesium was passed into the honey.

While the levels of radioactivity in the honey were generally not dangerous at the time of the study, the findings raised the question of how radioactive honey had been at the time of the tests decades earlier.

4. Very slightly radioactive steel across the world

You might be surprised to hear that steel produced before 1945 is considered especially valuable for some uses. It’s referred to as low-background steel. What that means is that it isn’t contaminated with radioactive fallout.

Yes, radioactive fallout from the world’s nuclear testing is now inescapable in the air. Since steel is produced in a process involving air, essentially all modern steel has traces of those radioactive isotopes. Normally, that’s not a big problem.

However, some devices, like Geiger counters, need to be made from steel that’s free of even those tiny remnants of radiation. Sometimes, wrecks of pre-1945 ships are even plundered for their low-background steel.

5. Health and the environment in the Marshall Islands

A place that has borne some of the worst effects of US nuclear bomb testing is the Marshall Islands in Micronesia.

After World War II ended, the USA continued nuclear testing, and one site of those tests was the Marshall Islands, then a US territory. 67 nuclear bombs were exploded on these islands. Waste from nuclear testing in Nevada was also stored there.

Some of the land, like the famous Bikini Atoll, became uninhabitable because of its levels of radiation. To this day, the Marshallese people continue to suffer increased levels of cancer due to the fallout. The environment of the now-independent Marshall Islands also continues to be contaminated.

To learn more about how it all began, read about the details of the first successful atomic bomb test in Alamogordo, New Mexico.