Billions of dollars of public funds may be expended needlessly to comply with overly restrictive regulations for environmental clean-up and waste disposal unless the EPA's proposed Federal Guidance on "Health Risks from Low-Level Environmental Exposure to Radionuclides" is revised to reflect current scientific understanding. A new Bill in Congress may force the EPA to do just that.
This EPA report provides federal agencies and other organizations with consistent methods for the assessment of cancer risks from exposure to 100 different radionuclides in the environment. Cancer risk estimates are expressed on a per disintegrating atom basis. By expressing risk in this way, the EPA perpetuates the philosophy that any radiation dose, no matter how small, is potentially harmful.
The EPA's position is not supported by current science. During the past 50 years, a large body of scientific information shows that large doses of ionizing radiation can cause cancer in humans. Increases in cancer have been detected only when the radiation dose exceeded 10,000 millirem given in a short time. For comparison, airline passengers safely get only about 5 millirem traveling from New York to Los Angeles. Patients get 50 millirem from some medical x-ray procedures--also a safe dose. The EPA's report would have you believe that 1 millirem is harmful.
Radiation standards to protect the public have been established at doses where little information about radiation-induced cancer is known. Detecting an increase in cancer due to low-level radiation is difficult because cancer is a common disease with many different causes. According to the American Cancer Society, cancer is the second leading cause of death in the U.S. resulting in more than 500,00 deaths annually. Approximately one in 5 Americans will die of cancer.
In setting radiation standards, the Environmental Protection Agency, the Nuclear Regulatory Commission, and other nuclear regulators assume that any radiation dose, no matter how small, might cause cancer and the number of cancers produced is in direct proportion to the radiation dose. Regulators use this linear, no-threshold philosophy in the standards setting process to predict numbers of cancers due to exposure to low level radiation.
However, recent scientific studies suggest that this approach is overly conservative, leading to excessive regulatory compliance costs. Low level radiation may be less dangerous than commonly believed. In one study of the costs and benefits of federal social regulation-- regulations aimed at reducing occupational safety and health risks-- imposed compliance costs of about $9 billion annually for negligible risk-reduction benefits. Less restrictive standards would save the public billions of dollars without compromising the public health or safety. Nonetheless, proponents of current standards argue that risk conservatism is justified because it is prudent public health policy and low-level risks remain uncertain.
If the linear, no-threshold philosophy is unacceptable, what should be the basis for standards setting? Alternative theories to predict risk at low dose are as difficult to justify as the linear no-threshold model. There is no requirement that standards be based on any predictive model. Exposure limits could be based on the average natural background level to the U.S. population (about 200 millirem per year). Scientific studies of populations around the world exposed to background levels several times the U.S. national average have not detected increased health effects due to background radiation.
How the linear, no-threshold theory debate will be resolved is anyone's guess. Prominent organizations such as the Health Physics Society and Canada's Advisory Committee on Radiological Protection have questioned the validity of the linear no-threshold theory; the International Commission on Radiological Protection continues to support it. The Environmental Protection Agency and the Nuclear Regulatory Commission are unlikely to make any decisions to continue using the linear no-threshold theory in setting limits until the National Council on Radiation Protection and Measurements and the National Academy of Sciences have completed their independent reviews and offer recommendations. That could take one or two years.
Regardless of how occupational and public exposure limits are set, they should be based on the best scientific information currently available and sound policy judgements. However, a dozen federal agencies have responsibilities for setting nuclear standards. These agencies operate under different laws, which may result in conflicting, duplicative or overlapping regulations. Nuclear regulations to protect the unborn child are in conflict with regulations to protect the general public. Nuclear Regulatory Commission regulations limit exposure of the unborn child of a pregnant worker to 500 millirem but exposures of members of the general public are restricted to 100 millirem per year. The Environmental Protection Agency, Nuclear Regulatory Commission, and Department of Energy have all issued duplicative limits on public exposure to radiation.
The EPA Federal Guidance report is a good example of the need for legislation such as HR 3234 that addresses the requirement for good science as a foundation for regulatory decision-making. The Science Integrity Act was introduced in the U.S. House of Representatives in February and requires the EPA and other regulatory agencies to have outside expert review of scientific data used in support of regulations. HR 3234 requires that reviewers be provided with all scientific data in support of the proposed regulation and any other related data requests. Reviewers' analyses are subject to public comment. The proposed legislation also provides for the establishment of the Office of Regulations Integrity with authority to review regulations issued by each department or agency. Although the EPA Federal Guidance is not "regulation," it may be used in rulemaking.
Kenneth L. Mossman is professor of Health Physics and Director, Office of Radiation Protection, Arizona State University, Tempe, AZ
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