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What Is Strontium-90?
Strontium-90 is produced only by atomic bombs, nuclear submarines and nuclear reactors. It is a good element to study because it has a long half-life, 28.7 years, and is easy to test.

Strontium-90 is chemically similar to calcium, following calcium through the food chain and appearing in human bone and teeth. Thus, strontium-90 found in baby teeth has been transported through the milk of dairy cattle that have eaten vegetation containing the material. Strontium-90 is found only in baby teeth because the adult body rejects the material in favor of calcium.

Like all radioactive materials, strontium-90 can be measured precisely at extremely low levels. The U.S. Department of Energy and its predecessor agencies have monitored strontium-90 levels since the early 1950s. Radiation safety programs at nuclear power plants monitor and analyze air and water releases—including specific analysis for strontium-90—using state-of-the-art sampling techniques and laboratory analysis. These monitoring programs—which are subject to strict oversight by the NRC and states—provide the government with accurate information that is published on a regular basis and available to the public.

The multiple safety barriers and constant monitoring used at nuclear power plants ensure any strontium-90 releases are so small that they would be undetectable in comparison with the amount of strontium-90 already in the environment from weapons testing. These levels are well below government limits. No credible scientific study has shown that the levels of strontium found in the environment pose a health risk. It is misleading and reckless to equate the mere presence of a radioactive isotope—many of which are produced naturally by the environment and by the human body—with adverse health effects. Claims of a link between strontium-90 and breast cancer are not supported by sound science.

A Legacy of Questionable Science and False Claims
The latest round of claims actually is based on a twisted variation of scientific studies on baby teeth during the early days of the Cold War. Scientists began to complain that the government was regularly testing atomic bombs domestically without knowing the effects it would have on the public. The campaign to collect baby teeth started in 1959 at Washington University in St. Louis. Strontium-90 was chosen as a proxy for the dozens of slow-to-decay radioactive compounds in nuclear fallout because it was easy to detect in testing.

There are three sources of strontium-90 in the environment: fallout from nuclear weapons testing, releases from the Chernobyl accident in the Ukraine and minute releases from nuclear power reactors. Even today, strontium-90 from weapons testing fallout is by far the largest source.

The validity of the tooth study has been questioned by the scientific community. In 1964, scientist John Harley, of the U.S. Atomic Energy Commission’s Health and Safety Laboratory, questioned the use of teeth to determine health effects from fallout during weapons testing. Harley wrote: “Among the available monitoring systems, the use of deciduous teeth or other teeth does not offer any advantage.”

A 1970 American Academy of Pediatrics committee also criticized the hypothesis linking fallout from nuclear weapons tests to health effects. It called the tooth fairy study conclusions “unfounded and unsubstantiated.” The original study eventually was abandoned.

RPHP was founded in 1985 and acquired the baby teeth left over from the Cold War study. RPHP began altering the original research purpose of examining the teeth and instead used them as a means to seek the closure of nuclear power plants.

A 1990 NIH study, “Cancer in Populations Living Near Nuclear Facilities,” evaluated cancer deaths occurring between 1950 and 1984 in 107 counties with nuclear installations and certain adjacent counties in the United States. The peer-reviewed study found:

• “Overall, and for specific groups of nuclear installations, there was no evidence to suggest that cancer mortality in counties with nuclear facilities was higher than, or was increasing in time faster than, the mortality experience of similar counties in the United States.
• “This study has found no suggestion that nuclear facilities may be linked causally with excess deaths from leukemia or from other cancers in populations living nearby.”

A 1991 National Cancer Institute study also is at odds with the RPHP claims, finding no general increased risk of death from cancer for people living near 62 reactors.

Zdenek Hrubec, a biostatistician who worked on the 1991 National Cancer Institute study, said it is difficult to imagine a case where reactors caused an increase in cancer that was hidden in the statistics. “You’d have to postulate that there was a deficit of smokers or industrial pollutants in the same places where there were nuclear reactors.”

In 1999, RPHP announced preliminary findings of a study claiming a greater risk for women in some counties in Long Island, N.Y., of developing breast cancer, based on evidence gathered in its baby tooth study. This study focused on the Millstone, Oyster Creek and Indian Point nuclear plants. The NIH’s National Cancer Institute conducted a study to investigate the incidence of breast cancer on Long Island. The study concluded that established risk factors—age, family history and genetic markers—appear to be the main reason for the breast cancer clusters in the Northeast and Mid-Atlantic.¹

Those involved with the “tooth fairy project” claimed they found high levels of strontium-90 in baby teeth near the Turkey Point and St. Lucie plants in Florida. However, the Florida Department of Health monitors radiation levels at locations around the state’s nuclear plants and has found no emissions that would harm the citizens of Florida.

In 2001, the American Cancer Society concluded that although reports about cancer case “clusters” in some communities have raised public concern, studies have shown that clusters do not occur more often near nuclear plants than they do by chance elsewhere in the population. Likewise, there is no new evidence that links strontium-90 with increases in breast cancer, prostate cancer or childhood cancer rates.

“Ionizing radiation emissions from nuclear facilities are closely controlled and involve negligible levels of exposure for communities near such plants,” the American Cancer Society said.

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¹ “Report to the U.S. Congress: The Long Island Breast Cancer Study,” Department of Health and Human Services, November 2004.

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