Sacramento cancer rate dropped after shutdown of Rancho Seco reactor – 4,319 cancer cases prevented

The first long-term study of the full-population health impacts of the closure of a U.S. nuclear reactor found 4,319 fewer cancers over 20 years, with declines in cancer incidence in 28 of 31 categories – 14 of them statistically significant – including notable drops in cancer for women, Hispanics and children.

Rancho-Seco-closed-reactor-adjacent-solar-panel-array, Sacramento cancer rate dropped after shutdown of Rancho Seco reactor – 4,319 cancer cases prevented, News & Views Published in the peer-reviewed medical journal, Biomedicine International, the major new article, “Long-term Local Cancer Reductions Following Nuclear Plant Shutdown,” is the work of epidemiologist Joseph Mangano, M.P.H. M.B.A., executive director of the Radiation and Public Health Project, and internist and toxicologist Janette Sherman, M.D.

Mangano and Sherman conclude that further research is warranted to determine if there is a cause-and-effect relationship between the elimination of radioactive emissions from nuclear power plants and significant long-term declines in human cancers.

At the heart of the article is the Rancho Seco nuclear reactor project in Sacramento County, an area with a relatively large 2010 population of more than 1.4 million. Rancho Seco has been closed for over 23 years, providing a long period to examine post-shutdown local health patterns. The closest operating nuclear plant is Diablo Canyon, over 200 miles to the south. Mangano and Sherman examined official California Cancer Registry data on cancer incidence for Sacramento County versus the entire state, using the last two years of reactor operation, 1988-1989, as a baseline for analysis.

The Mangano-Sherman study will resonate far beyond California. The 104 aging U.S. reactors at 65 plants affect many Americans. According to the 2010 U.S. Census, over 18 million Americans live within 20 miles of a nuclear power plant, and over 116 million live within 50 miles. Major populations live nearby other idled reactors: Los Angeles (San Onofre 1), New York City (Indian Point 1 and Shoreham), Chicago (Dresden 1 and Zion), San Diego (San Onofre 1), Portland (Trojan), New Haven (Millstone 1 and Connecticut Yankee), Providence (Millstone 1), and Harrisburg (Three Mile Island 2).

Author Joseph Mangano said: “This article is the first of its kind: No other peer-reviewed journal article has examined long-term changes in health status near closed nuclear plants. The need here for more knowledge is great, given how many reactors are near major population centers. San Onofre, in Southern California, has 8.4 million persons living within 50 miles. Indian Point, in southern New York, has 17.2 million within 50 miles. We need more information about the long-term impact of low-level radiation from both idled and currently operating reactors.”

Author Janette Sherman said: “The potential effects of locating new reactors should be measured not only in terms of health, but also in terms of cost. For example, the 4,319 fewer cancers than expected in Sacramento County during the first 20 years after the Rancho Seco closure translates into many millions saved in direct medical costs, reduction of productivity lost, and additional savings associated with the value of a human life.

“With large numbers such as these, and with the future of this source of power a matter of great public concern, reports like this one must be followed by similar efforts to attain better understanding of potential improvements in public health after reactors are shutdown.”

Other key findings in the article include the following:

  • Declines in Sacramento County cancer were observed for both men and women. The change was four times greater in women than in men, so it was statistically significant only for women. Among the four types of cancer with a significantly decreased standardized incidence ratio (SIR) were cancers of the female breast and thyroid. These malignancies were found to have the highest excess relative risk among Hiroshima and Nagasaki survivors from 1958 to 1987.
  • From 1988-1989 to 1990-1994, the Sacramento County child cancer rate for age 0-19 fell from 17.92 to 15.49 cases per 100,000 population, a drop of 13.6 percent, while the state rate remained virtually unchanged. Over the next two five year periods, the county rate continued to decline before rising in 2005-2009 – to a level still lower than in the late 1980s. Children age 0-2 and 2-16 years have been estimated to be 10 and 3 times more sensitive to radiation exposure, respectively, than adults. The developing fetus undergoes rapid cell proliferation, self-programmed cell death (apoptosis) and cell re-arrangement. The developing infant is similarly susceptible to cellular and metabolic damage. Unrepaired damage becomes magnified with time.

The Mangano-Sherman long-term findings are mirrored in earlier studies covering shorter periods of time. Examination of the short-term local health status changes in young persons immediately after shutdown of eight U.S. nuclear plants between 1987 and 1997 compared infant mortality for the two years before shutdown (including shutdown year) with the two years following. Rates in each of the eight areas decreased more rapidly than in the U.S. as a whole; the total decline for the eight areas was -17.4 percent vs. -6.4 percent nationally. The three areas for which cancer incidence was available showed a decrease of -25.0 percent in children age 0-4 vs. a rise of 0.5 percent for the entire U.S.

“Seeing an improvement in health outcomes after a known hazardous factor is stopped is not new,” observes Dr. Sherman. “Examples include the recent decrease in breast cancer since the use of HRT (Hormone Replacement Therapy) was stopped; the decrease in lung cancer with the decrease in smoking; and, of course, the historic reference to John Snow in London when he removed the handle from the Broad Street well and stopped the spread of cholera by cutting off its source in 1854.”

About the authors

Epidemiologist Joseph Mangano, M.P.H. M.B.A., is the executive director of the Radiation and Public Health Project. He is the author or co-author of 30 peer-reviewed medical journal articles and letters and author of the books “Low Level Radiation and Immune System Disease: An Atomic Era Legacy” (1998), “Radioactive Baby Teeth: The Cancer Link” (2008) and “Mad Science: The Nuclear Power Experiment” (2012).

Janette Sherman, M.D., is an internist and toxicologist and the author or co-author of many scientific publications. She is author of the books “Chemical Exposure and Disease: Diagnostic and Investigative Techniques” (1994) and “Life’s Delicate Balance: Causes and Prevention of Breast Cancer” (2008).

This press conference on the release of the study, featuring Mangano and Sherman and other experts, was recorded on March 28.