Answer to Question #12601 Submitted to "Ask the Experts"

Is it safe to live in areas where there was fallout from the nuclear testing done in Nevada many decades ago? Much of southwestern United States and parts of Idaho, Wyoming, and other areas were hit, to my knowledge. Is the area previously contaminated by the Hanford accident safe to live in as well?

I was asked to answer this question, in part, because I've spent much of the last 30 years studying the environmental contamination from nuclear testing and the nuclear weapons complex and the related health risks from exposure to that contamination.

First, let me note that there is not a simple definition of the "areas where there was fallout." Scientists have determined that everywhere in the world, and particularly the northern hemisphere, has some degree of residual radioactivity from atmospheric nuclear testing conducted by five countries (United States, Union of Soviet Socialist Republics, United Kingdom, France, and China). Areas that received contamination can primarily be distinguished by their degree of contamination rather than by delineation of areas with or without contamination. This makes your question difficult to answer in precise terms.

Second, I want to note that in the United States, the most contaminated areas are on the Nevada Test Site itself and are not available for public residences. Hence, your question must be rephrased to ask about the safety of living in the most highly contaminated areas in the United States that are open to the public. In 2006, my colleagues and I discussed in a published article the environmental contamination of long-lived radioactivity across the United States (Simon et al. 2006). You can find a map of cesium-137 (¹³⁷Cs) contamination across the United States in Fig. 7 (p. 53) of the article. That figure shows that about half the states in the United States received contamination that might be considered anywhere near significant. ¹³⁷Cs, however, disappears naturally by radioactive decay and is reduced in half every 30 years, so now it is has declined almost 75%. Moreover, and I would like to stress this, there is nowhere in the United States, other than perhaps on the nuclear test site itself, where the residual activity from radioactive fallout would expose people living there to more than a few percent of the allowable dose for members of the public. I interpret this to mean that there is nowhere that you might choose to live in the United States that is not safe due to residual fallout radioactivity.

Let me now address your concerns about Hanford. The site at Hanford, Washington, produced weapons-grade plutonium and today houses high-level nuclear waste. There has been no accident at Hanford resulting in any significant off-site contamination. You might review a well-written article on Wikipedia. There was an experimental, intentional release of iodine-131 (¹³¹I) there in 1949, but ¹³¹I has a short half-life (only eight days) so there was no permanent contamination. There have been a few significant exposures on-site and a tunnel collapse in 2017, but no recorded accidents that resulted in offsite contamination.

Steven L. Simon, PhD, FHPS

Reference

Simon SL, Bouville A, Land CE. Fallout from nuclear weapons tests and cancer risks. American Scientist 94:48–57; 2006.