The statistics seem clear and compelling, and completely at odds with common sense: In Japan, site of the world's only nuclear attacks, radiation victims are outliving their peers.
It's one of the stranger twists in 50 years of scientific monitoring of atom bomb survivors. As expected, the people closest to ground zero have died in high numbers of cancers that began in a white-hot flash of nuclear radiation. But as one moves farther from the blast site, the death rate plunges until it actually dips below the baseline.
And so, oddly, people with limited radiation exposure appear to live longer than neighbors who had none at all.
The discrepancy has several possible explanations, but none of them have quelled the growing debate over what the data seem to suggest: Could low-level radiation—regulated in this country and elsewhere as a powerful carcinogen—be less dangerous than commonly believed?
The question, which has divided scientists and academicians for years, has flared again because of a number of provocative new studies that seem to refute prevailing views about low-level radiation—the relatively low-grade sort found in some kinds of medical waste or in the natural radon gas found in many homes.
"It's like a religious dispute," said Steven Galson, the Energy Department's chief medical officer. "It's very, very intense."
The issue has broad implications, not just for nuclear workers but for ordinary consumers and taxpayers. If the government relaxed radiation exposure standards, by even a small degree, it could result in enormous savings for utilities, hospitals and other businesses that use radioactive materials. Taxpayers could save billions of dollars if cleanup standards were eased for the dozens of lightly contaminated sites around the country.
There's no sign that such a change is imminent. Some long-term epidemiological studies continue to suggest risks from even the most minute quantities of radiation. But others are challenging the conventional wisdom in ways that are becoming harder to ignore. Here are a few of the recent findings:
Tens of thousands of Navy shipyard workers were exposed to radiation in the 1960s and 1970s. Yet, in carefully controlled epidemiological studies by Johns Hopkins University, the radiated workers appear to have suffered no ill effects. In fact, they have fewer cancers than non-exposed workers.
Thousands of soldiers took part in nuclear weapons tests in the early years of the Cold War. But in a pair of recent analyses, researchers found no sign of unusual illnesses or higher death rates among these "atomic veterans."
A University of Pittsburgh researcher tracked cancer rates in American counties with the highest levels of radon, the naturally radioactive gas. His finding: Lung cancers are lower in the areas where exposure is the highest.
Each case has been met with criticism over possible flaws that may have skewed the results. One problem is that epidemiological studies, which track human illness and deaths over time, can be relatively crude instruments for measuring health effects. "It's like hitting an ant with a hammer," said the Energy Department's Galson.
To help resolve the dispute, a committee of the National Academy of Sciences gathered in Washington recently to launch a months-long project to decide whether the latest evidence on low-level radiation and health should be formally reviewed. A similar review is underway at the National Council on Radiation Protection and Measurements, the congressionally chartered board that helps advise the government on radiation safety.
It's too early to predict the outcome, but already prominent scientific groups are taking sides. Last year, the Health Physics Society, a professional association of scientists who study the health effects of radiation, surprised many observers when it effectively rejected the government's existing guidelines as too conservative.
Others take a more cautious view. Some, like the Environmental Protection Agency's Jerry Puskin, have observed that many of the most vocal advocates for change have their own reasons for wanting to see nuclear-based technologies succeed. "If you already have an agenda, you tend to grab on to these things," Puskin said.
At the core of the debate is a simple but powerful theorem, born amid the uncertainty and anxiety of the atomic era. It states that all radiation is harmful—and the more radiation, the greater the harm. Known among scientists as the "linear no-threshold" model, it holds that there is no truly "safe" level of exposure because even a single radioactive particle could cause damage to cells that could lead to cancer.
This model guided U.S. regulators in setting exposure limits for radiation in the 1950s, and it continues to do so today. The government's exposure limit for most Americans is 0.1 rems a year, a level lower than the average person's exposure from natural radiation sources (The average American receives 300 millirems of radiation from natural sources each year.)
Radiation is simply energy in movement and can take the form of high-speed particles or electromagnetic waves. The weaker, or "nonionizing," forms of radiation include visible light and radio and television waves. Considerably more powerful is "ionizing" radiation, so named because it packs enough energy to strip electrons from atoms.
At high levels, ionizing radiation can do serious damage to the genetic material within cells. Damage can also occur at small doses, but it is "indistinguishable, at the cellular level, from the damage routinely experienced from metabolism," argues Theodore Rockwell, of Radiation, Science and Health Inc., a pro-nuclear group.
In the March edition of the journal The Scientist, Rockwell notes that living cells have adapted over billions of years to natural radiation that is present in virtually every rock, and which bombards Earth daily from space. He dismisses as "silly" government standards that attempt to control radiation at levels smaller than a typical tourist encounters by walking through naturally radioactive granite halls in the U.S. Capitol.
"Even sleeping with another person or moving to a hill or up 10 floors of a building increases one's radiation dose beyond the permissible minimum," he wrote.
At the very least, Rockwell and others who share his views hope the debate will result in a better public understanding about radiation. In the United States, in contrast to other Western countries, fear of radiation has led to public rejection of nuclear power as an energy source. It also fuels public suspicion about such potentially beneficial technologies as food irradiation, which can kill deadly pathogens and reduce the waste of food through spoilage, they say.
"In the United States we have taken the position that radiation is so dangerous we don't want anything to do with it," said David P. Hickman of the federal Lawrence Livermore National Laboratory. "There's a real question of whether we may be hurting our future."
Measuring Radiation's Effects
People are exposed to radiation in many ways, and about five-sixths of the exposure comes from natural sourcesActivity Millirems Typical yearly exposure, all sources 360.00 Yearly exposure from natural sources 300.00 Full set of dental X-rays 40.00 Chest X-ray 8.00 Flying round-trip from D.C. to L.A. 5.00 Watching TV for one hour 0.15 Living outside nuclear power plant for one year 0.10
Compared with other health risks, radiation poses little risk for most Americans, reducing life expectancy about 18 days Health risk Expected life lost Smoking a pack of cigarettes a day 6 years Being 15 percent overweight 2 years Moderate alcohol consumption 1 year Working in agriculture 320 days Working in construction 227 days Working in nuclear plant (1,000 mrem/yr) 51 days Typical annual radiation dose
(360 mrem/yr)18 days Material presented on this home page constitutes opinion of the author.
Copyright © 1997 Steven J. Milloy. All rights reserved. Site developed and hosted by WestLake Solutions, Inc.