In 1945, in the heart of the New Mexico desert, at a location known as Trinity, the world’s first nuclear bomb test detonation took place. The test, code-named Trinity, was highly secretive, and the only witnesses were eminent scientists, including Fermi, Feynman, Oppenheimer, and von Neumann. Information about this event was kept hidden from the general public. Even the governor of New Mexico only learned about the nuclear tests after the bomb was dropped on Hiroshima.
An interesting aspect of this event is the role played by the company Kodak, whose remarkable discovery led to the exposure of the nuclear test secret. The story began with a faulty film roll that Kodak discovered while developing unused material. The appearance of dozens, or even hundreds, of small dark spots on the film suggested that it had been exposed to nuclear radiation, even though it had never been taken out of its packaging. Julian Web, an employee of Kodak, informed the company about his discovery. He wrote a letter seeking an explanation, but it was immediately classified. The declassified contents of that letter can now be read on the website of the ORAU – Museum of Radiation and Radioactivity in the United States.
Recycling of Radioactive Materials
This phenomenon was not new. During World War II, radium was widely used to produce luminescent materials, such as aircraft dials and instruments. The alpha radiation emitted by radium made these items glow in the dark. Some radium settled on paper and cardboard in factories, and due to raw material shortages, remnants of paper products were recycled. This led to the presence of small amounts of radium in commonly available paper products.
When this paper was used to package Kodak film rolls, the radiation from radium exposed the film even before its use. This problem was significant enough that Kodak had to make changes in its supply chain. They selected only a few paper manufacturing companies that strictly controlled their raw materials. One of these facilities was located in Vincennes, Indiana, near the Wabash River, where the cardboard plate was produced and placed between the sheets of film.
For several months, everything went smoothly until the batch produced on August 6, 1945, began to cause spots on X-ray films. At that point, scientist Julian Webb, working for Kodak, was tasked with resolving the issue. Webb drilled holes in the cardboard at the spot where the film was exposed, and then he measured the alpha particles emitted by the material. The radiation level did not differ significantly from the background, ruling out the presence of radium and other naturally occurring isotopes of uranium, thorium, and actinium, all of which emit alpha particles. However, when measuring beta radiation, significant activity was observed, consistent with the results seen on the X-ray films. This radiation penetrated several layers, characteristic of beta particles rather than alpha. Over the following months, Webb measured the half-life of the radioactive substance, determining it to be about 30 days. Based on the half-life and energy of the beta particles, Webb concluded that the most likely radioactive contamination was cerium-141 (Ce), an isotope that could only come from a nuclear fission explosion.
Discovery by a Physicist Working on the Manhattan Project
This discovery was relayed to Los Alamos scientists, who wanted to learn more. A Los Alamos consultant wrote to Webb, inquiring about the amount of radiation per square mile, the size of the particles that fell, and the half-life of the radioactive substance. Webb conducted his research until the end of 1945 but only published it in 1949 in the Physical Review. He was aware of how sensitive these findings were, considering that he himself worked on the Manhattan Project in Berkeley and Oak Ridge, where electromagnetic techniques were used for uranium isotope separation.
The film manufacturer, Kodak, realized that it had to take steps to protect its materials from nuclear radiation. Air samplers were installed to monitor radioactive fallout in their buildings. Radioactive fallout was a crucial concern as nuclear bomb tests caused atmospheric contamination. The United States government realized that it had to carefully consider the locations for conducting tests to minimize their effects. They needed locations closer to weapon laboratories and with available aerial support. Ultimately, Nevada was chosen, located almost on the western edge of the country, just 150 kilometers from Las Vegas. The argument for this location was the proximity to the weapon laboratories, which would expedite their development work. After the first atomic bomb test in Nevada in 1951, Kodak detected radioactive fallout at its headquarters in Rochester, New York, over 3,200 kilometers away. After a snowstorm, Geiger counters showed readings 25 times higher than normal background levels. Kodak threatened the U.S. government with a lawsuit for significant damages caused to their products due to the tests in Nevada or subsequent nuclear tests.
Photographic Industry Reached an Agreement with the Government
As a result, an agreement was reached between the Atomic Energy Commission and Kodak. The Atomic Energy Commission would warn Kodak and the entire photographic industry about upcoming tests and provide forecasts regarding the distribution of radioactive fallout based on meteorological models. In return, Kodak agreed to remain silent about radioactive fallout. From 1951 to 1963, the United States conducted one hundred nuclear tests on the surface in Nevada. This resulted in a radioactive mixture, which, as predicted, was dispersed by the wind across most of the country. When these radioactive atoms settled on agricultural land, they were ingested by livestock or absorbed by plants, becoming part of the food chain. Radioactive iodine-131, consumed by cows, was transferred to humans through milk. This was particularly dangerous because iodine is concentrated in the thyroid glands, and children consume the most milk, and their thyroid glands are still developing. It is estimated that nuclear tests led to tens of thousands of additional cases of thyroid cancer.
Radioactive Teeth and Bones
The Atomic Energy Commission was not too concerned about radioactive iodine-131 because it has a very short half-life, only eight days. Strontium-90 (Sr-90) caused greater concern due to its half-life of nearly 30 years. Strontium-90 behaves chemically in the body like calcium, so after ingestion, it settles in teeth and bones. It emits beta radiation, which can cause bone cancer, tumors in surrounding tissues, or leukemia.
Studies were conducted to determine the effects of radioactive fallout. For example, the “Baby Tooth Survey” in St. Louis collected 320,000 baby teeth from children born between 1950 and 1970. It turned out that children born in 1963 had 50 times more strontium in their teeth than those born in 1950 [source: Baby Tooth Survey].
Over the years, concerns about the effects of radioactive fallout on human health persisted. While there is disagreement about the specific effects of these tests, studies show correlations between disease occurrence and the absorption of radioactive isotopes. After signing the Partial Nuclear Test Ban Treaty in 1963, which prohibited nuclear tests in the atmosphere, underwater, and in space, there was a decrease in the concentration of radioactive fallout. However, further research is still needed to examine the long-term effects of these tests.
It is also essential to understand that radioactive fallout is not the only threat associated with nuclear tests. These tests also emit large quantities of greenhouse gases and are linked to severe environmental and ecosystem consequences. Therefore, limiting and monitoring nuclear tests remains critical in the context of global security and environmental protection.
The radioactive fallout resulting from nuclear tests influenced public awareness and led to the creation of international treaties that restrict and regulate nuclear weapons testing. As technological advancements continue, methods for detecting radioactive contamination have also been developed and find applications in various fields, such as healthcare, forensic science, and historical artifact dating. Furthermore, Kodak’s discovery of nuclear radiation had long-term consequences for the photographic industry. After restrictions on nuclear testing were imposed, the photographic and film industry had to adapt its production processes and protect its products from radiation. Thanks to this experience, Kodak became a leader in monitoring and preventing radioactive contamination.
However, the consequences of nuclear tests still exist in our environment and health. Radioactive isotopes such as strontium-90 and iodine-131 are still present in our bodies. Although radiation levels are currently lower than in the past, further research is needed to examine the impact of these isotopes on human health.
Finally, Kodak’s discovery demonstrates how science and technology can aid in detecting and studying the effects of nuclear radiation. Methods such as the analysis of radioactive isotopes can be utilized in various fields, from forensic science to historical artifact dating. This shows that even the most unexpected scientific discoveries can have broader applications and contribute to our knowledge of the world.