Challenges to Radiation Limits Getting Harder to Ignore

Article excerpt

In Japan, the only nation ever to have been subject to nuclear attack, radiation victims are outliving others of the same age.

Half a century of monitoring of atom bomb survivors has found - as expected - that, 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 drops until it actually dips below the baseline.

The finding has raised a question: Could ionizing radiation in small doses actually be good for you? Could it be like so many other substances - iodine, for example - that are lethal in excess but essential to good health in trace amounts? The finding is likely to change the rules of the game in the long-stan ding debate over low-level radiation. Because it is found in so many places, including medical trash, nuclear power plants and in the natural radon gas found in many homes, strict control standards have been costly. 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 dozens of lightly contaminated sites. There's no sign that such a change is imminent. Some long-term 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 recent findings: Tens of thousands of U.S. Navy shipyard workers were exposed to radiation from nuclear-powered warships in the 1960s and 1970s. Yet, in carefully controlled 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 Cold War. But in a pair of recent analyses, researchers found no sign of unusual illnesses or higher death rates among t"atomic veterans." A University of Pittsburgh researcher tracked cancer rates in American counties with the highest levels of radon, the radioactive gas that is found in rocks. 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 studies that track human illness and deaths over time are relatively crude instruments for measuring health effects. 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. …