A Culture of Safety?
I recently attended my first radiation safety training here at MIT. Far from being balanced or even accurate, I left feeling as if it had served only to dismiss the very real potential dangers of low-level radiation exposure and to promote the idea that radiation is good for you.
The training began by asking if there was a safe level of exposure. To my shock, the trainer said yes. He said that the background radiation we are all exposed to is harmless, and as proof, he made reference to studies that showed no statistically significant correlation between background dose and cancer rate. Thus he began the lecture by denying the most fundamental and widely accepted fact about radiation, namely that there is no safe dose. Even the DOE and the EPA, hardly anti-nuclear organizations, state that a person has about a 1 in 100 chance of developing cancer from background radiation. In fact, the slides we were given contained this result, but it was presented so as to make it nearly unrecognizable. In 1998, the National Academy of Sciences Committee on the Biological Effects of Ionizing Radiation issued their findings that exposure to indoor radon gas (which in some basements can reach concentrations comparable to those in uranium mines) was responsible for 10 to 14 percent of all lung cancers in the United States. This equates to roughly 15,000 to 22,000 people dying every year from just this source of natural radiation. Finally, several long-term studies of childhood cancer caused by exposure to X-rays while in the womb have demonstrated that there is no threshold below which there is no risk.
This seems at odds with the studies the trainer cited, but in examining their results, it is clear that they were simply unable to detect the change in cancer rate due to radiation because of the much larger, non-radiation-related fluctuations. According to Dr. Gofman, Professor Emeritus of medical physics at U.C. Berkeley and former associate director of the Lawrence Livermore National Laboratory, the expected increase in cancer for doubling the average, non-radon background dose should be roughly 16 percent. In two typical studies, the fluctuation of cancer rates for areas of equal background was roughly 40 percent, and thus it is not surprising that the radiation effect was not statistically observable. In fact, a recent British study, after taking cofactors into account, did find a significant correlation between childhood cancer rates and local background radiation. They went on to estimate that as much as 75 percent of all childhood cancer in the United Kingdom is caused by fetal exposure to background radiation in the highly sensitive first trimester. As a final example, when an extreme case was studied, such as Kerala, India (which has high levels of thorium in its sand), the effects of spontaneous abortions and mental retardation were documented more than 25 years ago.
As if to provide a sense of symmetry, the hour of training concluded with a “discussion” of the models for the effects at all levels. As with the discussion of background radiation, the trainer did not focus on the widely accepted theory, but instead focused on “radiation hormesis.” This is a fancy phrase that means “low levels of radiation are good for you.” He spoke about the proposed cellular mechanisms and went on in some detail about how two different studies found that nuclear workers were healthier than the general population.
Of the two radiation worker studies he presumably referred to, the first was conducted by the International Atomic Energy Agency, whose mission statement includes assisting “in planning for and using nuclear science and technology for various peaceful purposes.” Thus the IAEA has the same conflict of interest that forced the Atomic Energy Commission to be disbanded because the public could not trust them. The second study was conducted by the United Kingdom National Radiological Protection Board, which is similar in function to our Nuclear Regulatory Commission. In the seventh report of the NRPB’s Committee on Medical Aspects of Radiation in the Environment (COMARE), they themselves note that “improved worker health” is observed in many non-nuclear industries and is commonly referred to as the “healthy worker effect.” In other words, the nuclear industry (like many others) selects for highly educated, healthy people who get paid well, have good insurance, and have access to quality health care and thus it is not surprising that they are healthier than the population as a whole.
Even more important than focusing just on potential “benefits” of radiation, the trainer failed to mention that the same COMARE report contains significant evidence that children of nuclear workers are at increased risk of developing leukemia. This pre-conceptual effect was first proposed by Gardner et al. in the British Medical Journal in 1987 and has since been followed up by many laboratory and human studies. As with most epidemiological studies, there are those that found a significant correlation (for some as much as a five-fold increase in risk) and others that failed to do so. There were also many laboratory studies that showed not only a direct increase in the offspring’s cancer risk, but also an increased susceptibility to chemical and environmental carcinogens. Others showed less dramatic effects. Even if the “benefits” to the individual were widely accepted (which they are not), to focus on them and exclude other important potential genetic damage hardly seems balanced.
To be fair, the radioactivity we will be dealing with is low risk. This is because the sources are mostly low-activity, many are sealed into equipment or at the least very difficult to inhale or ingest, and all of them are routinely shielded. This, however, must not excuse the factual errors and misleading presentation of our radiation safety training. It is not for the Institute to play scaremonger or focus on only the worst-case. But, given that this will be the first safety training for most students, and, as such, will set the framework in which they will evaluate all subsequent information, it is just as important not to belittle the dangers of radiation as it is not to exaggerate them. For a scientist to ignore data, especially when there is uncertainty, just because it doesn’t fit with their preconceptions is a very serious matter. For a safety officer to do so not only sets a terrible example, but may put people at risk. To quote David Brower, former executive director of the Sierra Club and founder of Friends of the Earth, “If we’re wrong, we can do something else. If they’re wrong, we’re dead.”