Exposure to more than trace amounts of uranium can cause cancer and other diseases, which is why uranium mining has some of the world's strictest regulations.

Advocates of nuclear power argue it can play a key role in society’s transition away from climate-warming fossil fuels, since nuclear fuels like uranium do not emit climate pollution like coal, oil, and gas do. But nuclear fuels are dangerous substances, and proper precautions are needed to scale up their use without causing harm to the environment or to the workers mining the material.

Health risks related to mining uranium have been known for nearly a century, says Haruko Wainwright, MIT assistant professor of nuclear science and engineering and of civil and environmental engineering. In the 1930s, for example, after increased rates of lung cancer were found in miners (including children), mining companies put in early safety systems such as proper ventilation.

The atomic age boom in uranium came in the 1950s, when it was mined throughout the Southwestern U.S. to power the nation’s growing arsenal of nuclear weapons and its earliest nuclear power plants. However, Wainwright says, workers often did not know the risks of mining uranium, especially the rise in lung cancer risk via inhalation of uranium and its byproducts, and safety precautions such as ventilation were not always installed. This was especially true at mines where Native Americans worked, says Wainwright. Throughout the 1960s and 70s, members of tribes such as the Navajo mined uranium for the U.S. government in environments with slow and incomplete adoption of safety measures.

In the environment, the risk of uranium exposure is highest for communities near uranium mines or sites where it is milled into a usable form or enriched in preparation for use. Uranium exists naturally in the soil, rocks, and ocean, which means all of us are naturally exposed to a small amount of it, but large exposures are associated with cancers and kidney damage. To protect Americans, the EPA has instituted rules that set a safe limit for uranium in drinking water, mandate cleanups of accidental uranium waste releases, and regulate how abandoned uranium processing sites are dealt with (1).

The situation at American uranium mines has improved over the decades. Mines today are regulated by the Nuclear Regulatory Commission and Environmental Protection Agency. To protect the environment, they mandate, for example, that places storing uranium waste are constructed with a 1,000-year compliance period, meaning they are built to last without leakages for at least that long.

The vast majority of uranium mining today, however, is done outside the U.S. The top producers include both wealthy countries like Canada and Australia, and developing countries such as Namibia and Kazakhstan, the world’s top producer (2). Most uranium mining in Kazakhstan, and many other places, is now done through “in situ recovery”: instead of removing ore from the ground and treating it, miners use a chemical solution to dissolve the uranium-containing material and transport it to the surface in liquid form, where the uranium-containing minerals can be recovered. “It reduces hazards associated with digging and mining, but groundwater contamination is a concern,” Wainwright says.

While groundwater is heavily monitored in the United States, less is known about the effects in other countries. Some studies have indicated that areas of Kazakhstan around uranium mines have seen water contamination (3) and plausibly related health impacts (4,5).

Given the well-known health hazards, uranium mines tend to have the strictest regulations among mines. The World Nuclear Organization says that Canadian and Australian mines in particular are run in accordance with regulations to prevent workers from unsafe exposure. It also notes that although “most uranium mined is done so in countries with full adoption of international recommendations, this is not the case in all parts of the world” (6).

Indeed, Wainwright says it may be impossible to get accurate data on uranium mining safety in all parts of the world. “Mining has been often a hidden component from consumers, often disproportionately impacting rural regions and vulnerable populations,” she says. “It is important to develop mechanisms and regulations to protect workers’ health as well as the environment.”

Thank you to Julie Chapman of Portland, Oregon, for the question. You can submit your own question to Ask MIT Climate here.

Published July 10, 2023.

FOOTNOTES

1 U.S. Agency for Toxic Substances and Disease Registry: What Are the Standards and Regulations for Uranium Exposure? Accessed July 10, 2023.

2 World Nuclear Association: World Uranium Mining Production. Updated May 2023.

3 Zhanbekov, Khairulla, Almaz Akhmetov, and Augusto Vundo. "Twelve-Year Monitoring Results of Radioactive Pollution in the Kazakh Part of the Syrdarya River Basin." Environment and Natural Resources Journal, Volume 17, Issue 1, 2019, doi:10.32526/ennrj.17.1.2019.05.

4 Saifulina, Elena, et al. "Epidemiology of Somatic Diseases and Risk Factors in the Population Living in the Zone of Influence of Uranium Mining Enterprises of Kazakhstan: A Pilot Study." Healthcare, Volume 11, Issue 6, 2023, doi:10.3390/healthcare11060804.

5 Bersimbaev, Rakmetkazhy, and Olga Bulgakova. "The health effects of radon and uranium on the population of Kazakhstan." Genes and Environment, Volume 37, 2015, doi:10.1186/s41021-015-0019-3.

6 World Nuclear Association: Occupational Safety in Uranium Mining. Updated March 2020.