Published July 08, 2005
A federal research panel last week concluded that there is no safe exposure to radiation. It’s a conclusion based on assumptions about cancer that may be all wrong — and in very costly ways.
“The scientific research base shows that there is no threshold of exposure below which low levels of ionizing radiation can be demonstrated to be harmless or beneficial,” claimed Richard Monson, chairman of the National Academy of Sciences committee that just issued a report estimating the health risks of exposure to radiation from natural and manmade sources.
The committee estimated that 82 percent of the average person’s exposure to ionizing radiation is natural and unavoidable, coming at low levels from the universe and the ground. The other 18 percent of our radiation exposure, says the committee, comes from low-level man-made sources such as medical x-rays, nuclear medicine and consumer products such as tobacco, tap water and building materials.
No one disputes that exposures to very high levels of radiation can cause health problems — data indicate, for example, that the Japanese atomic bomb survivors experienced slightly higher rates of cancer over the 50-plus years that they’ve been studied so far — but it’s not clear at all that more typical, low-level radiation exposures pose any risk at all.
Other than the atomic bomb survivor data, in fact, no data support the idea that typical exposures to radiation are dangerous. So how did the NAS panel reach the conclusion that any exposure to radiation is risky?
For the sake of being able to somehow characterize low-level radiation exposures as a risk, the panel simply assumed that because high-level exposures to radiation increase risk of health effects — like the slightly elevated cancer risk observed in the atomic bomb survivors — then any level of radiation exposure is a cancer risk.
The panel employs this assumption even if the radiation is naturally occurring — that is from the ground or universe. This assumption is called the “no-threshold” model of cancer development, meaning the only radiation exposure with zero risk is absolutely no exposure — a state that is obviously impossible to achieve.
Such assumptions — known by the oxymoronic term “science policy” — are used by government regulators who want to regulate human activities and exposures but often lack supporting scientific data. In the face of scientific uncertainty, regulators typically make worst-case assumptions under the premise of erring on the side of over-protection.
Such assumptions often result in stringent regulation that is very costly, but that may not provide any, much less commensurate, health benefits. The regulations limiting human exposure to low-level radiation are not known to have prevented a single health effect in anyone despite decades of use. But they have cost more than $1 trillion in the U.S. alone, according to Radiation, Science and Health, an international non-profit group run by radiation experts who “advocate for the objective review of low-level radiation science policies.”
Guesswork about the alleged risk posed by low-level radiation is only part of the problem with the National Academy of Sciences report.
Over the last 30 years or so, the scientific establishment has become heavily invested in the notion that cancers are caused by genetic, or DNA mutations. The idea is that something — say a single molecule of a “cancer-causing” chemical, the smallest radiation exposure or even chance alone — can cause a change or mutation in a cell’s DNA, thereby turning a normal cell into a cancer cell.
In addition to regulation of radiation exposures, this supposition is the basic rationale that government regulators have relied on for decades to regulate exposures to chemicals allegedly linked with cancer risk — even though there is virtually no real-world evidence to support it.
But a new idea spotlighted by Tom Bethell in the July/August issue of the American Spectator should cause regulators to begin to re-think their decades-old-but-still-unproven assumption of gene mutation.
It was first noticed about a century ago that cancer cells exhibit “aneuploidy” — they don’t have the correct number of chromosomes. Aneuploidy occurs when cells divide improperly and a daughter cell winds up with an extra chromosome. An aneuploid cell may die, but it may also survive and repeat the error, perhaps eventually leading to cancer.
The problem with this idea is not so much scientific as political. Bethell points out that the man who “rediscovered” the old work on aneuploidy is controversial University of California-Berkeley researcher and National Academy of Sciences member Peter Duesberg, who famously had his grants from the National Institutes of Health cut-off for being critical of the direction of AIDS research in the late-1980s.
Duesberg still isn’t getting any NIH money even though his aneuploidy idea has survived early challenges, according to Bethell’s article, and the older notions of cancer development are going nowhere fast.
It seems that before regulators spend another $1 trillion of the public’s money on radiation protection that may be based on faulty assumptions, someone ought to throw some research money Duesberg’s way.
Steven Milloy publishes JunkScience.com and CSRwatch.com, is adjunct scholar at the Cato Institute, and is the author of Junk Science Judo: Self-defense Against Health Scares and Scams (Cato Institute, 2001).