The first ever long-term study examining the health impact idled U.S. nuclear reactors have on people living near the facilities found a significant drop in cancer incidents since the plant's closing, prompting researchers to call for further study of other populations near shuttered plants — including two in Illinois.
In a 20-year period since the California Rancho Seco nuclear reactor closed, there were 4,319 fewer cases of cancer reported in Sacramento County, which has a population of about 1.4 million. The shuttered plant is located about 25 miles from the center of Sacramento city.
The cancer drops were most notable in women, Hispanics and children, according to Joseph Mangano, executive director of the Radiation and Public Health Project, and co-author of the report published today in the Biomedicine International journal.
“The need here for more knowledge is great given how many reactors are near major population centers,” Mangano said on a conference call with reporters today. “The bottom line is clear. We need more information about the long-term impact of low level radiation from both idled and currently operating reactors.”
There are 127 U.S. nuclear reactors in the country, and 23 are retired.
Two idled U.S. nuclear reactors in Illinois, Dresden 1 and Zion, made Mangano’s list of other sites to study.
Dresden 1, or the Dresden Generating Station, is located in Morris and was active in the 1960s until it shutdown in 1978.
The Zion Nuclear Power Station in Lake County retired in 1998.
The researchers decided to look at Rancho Seco, instead of one of the other 23 permanently closed reactors, due to its proximity to a large metropolitan area, its long shut-down period and the lack of other nearby major reactors. California’s cancer registry also maintains county-specific incident data since before the plant closed in 1989.
“We had good data and lots of data to examine,” Mangano said.
Mangano and the other researchers examined the Sacramento County cancer incidents and compared them with state-level figures. They used the last two years of the reactor’s operation (between 1988 and 1989) as a baseline for the analysis.
After Rancho Seco closed, Sacramento County’s rate of cancer was 3.5 percent above the state’s figure, compared to 7.6 percent higher when the reactor was still operating.
“This is a significant decline, and this translates into the 4,319 fewer cancer cases,” Mangano said
The cancer decline was present in both males and females, however the decline was four-times greater in women.
Thyroid and breast cancer, which are particularly sensitive to radiation exposure, decreased the most.
Child cancer incidents also dipped.
In the first five years after the reactor closed, Sacramento County child-cancer rates for ages zero to 19 fell 13.6 percent, while the rest of the state remained virtually unchanged, according to the report.
After five years, the child-cancer county rate remained below the state's incidents.
“The federal government, unfortunately, has been caught up in a conflict of interest about the effects of ionizing radiation mainly because of its role in establishing nuclear weapons and usage of atomic energy to generate electricity,” said Robert Alvarez, senior scholar at the Institute for Policy Studies, who focuses on nuclear disarmament, environmental, and energy policies.
“I think we need to keep a careful eye on how the government proceeds in doing these studies, and that I think there needs to be much more support for independent studies of this kind.”
Janette Sherman, the study's other co-author and an internist and toxicologist, said the impact of reactors should be measured not only in terms of health, but also in terms of cost. For example, she said, the 4,319 fewer cancers than expected in Sacramento County during the first 20 years after the Rancho Seco closure translates into millions of dollars saved in direct medical costs, a reduction in lost productivity 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 ongoing efforts to attain better understanding of potential improvements in public health after reactors are shutdown,” she said.
Mangano said the findings were based on a large number of cancer cases, which greatly reduces the chances of this being “just some sort of random event that rates declined.”
“This is just the first article of its type. No one has ever looked before at what happens to local health after a nuclear plant closes,” he said. “This answers some questions, but it raises many others.”