Federal agencies battle over risks from low-level radiation exposure EPA says a Nuclear Regulatory Commission (NRC) proposal to set radiation cleanup standards on sites ranging from nuclear power plants to medical facilities using X-ray equipment is too lenient. The agency has threatened to put NRC cleanup sites on the Superfund list if the proposed rule is approved. The proposed radiological criterion for license termination, discussed at a meeting of the agencies April 21, reflects a larger scientific debate among regulators about the risks associated with low-level radiation exposures. EPA bases its risk estimates on controversial linear extrapolations of above-average cancer incidence among survivors of Hiroshima and Nagasaki. Tying these extrapolations to the risk guidelines in Superfund, the agency has established 15 millirem per year (mrem/yr) as the acceptable contamination level after cleanup For groundwater EPA uses a separate 4 mrem/yr limit based on requirements of the Safe Drinking Water Act However, the proposed stan-
dard, which would apply to closings of NRC-licensed facilities, would set one standard for both soil and groundwater at 25 mrem/ yr and allow for cleanup levels as high as 100 mrem/yr under the most difficult cases. According to EPA, a 100-mrem/yr dose creates a lifetime cancer risk of 1 in 200, seven times higher than would be permitted for other pollutants under Superfund. "To put it bluntly, radiation should not be treated as a privileged pollutant," said Ramona Trovato, director of EPA's Office of Radiation and Indoor Air, at the April 21 meeting. Over the past few years, EPA, NRC, and the Department of Energy (DOE) have tried to reach agreement on a national cleanup standard. An initial cleanup standard proposal by NRC in 1994 was followed by an EPA proposal in March 1996 that would have regulated all federal radiation cleanup activities under the Atomic Energy Act. That proposal would have set a 15-mrem/yr exposure rate for standard site cleanup and a 4-mrem/yr exposure rate for groundwater, and it would have permitted flexibility based on land use. But the agency withdrew that proposal in December amidst debate with DOE over costs. The debate about 15 mrem/yr versus 25 mrem/yr may fall well below the safe-level mark according to Richard Vetter president of the Health Physics Societv who said scientists cannot distinguish between low risk no risk below 5000 m r e m / y r Vpttpr said t h e av prapp vparly PYTIO siirp tn radiation is
Scientists from Oak Ridge Institute for Science and Education take samples to determine radiation cleanup level. (Courtesy 0RISE) 268
350 mrem/yr, from natural and man-made
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sources alike. The National Council on Radiation Protection and Measurements, a standards organization, sets the limit for public exposure from routine operation of a facility, such as a hospital X-ray room, at 100 mrem/year. Bill Morris, director of NRC's Division of Regulatory Application, Office of Research, said there can be a huge cost difference between 15 mrem/yr and 25 mrem/yr for cleanup of the tens of thousands of sites licensed by NRC. And the decreased risk associated with the added cost may be negligible, he said. EPA does support some built-in flexibility that should ease NRC's concerns, said Lawrence Weinstock, director of EPA's Radiation Protection Division. The agency would include future use of a site as a variable in the risk equation, easing cleanup requirements for nonresidential uses. This variable could account for the difference between 15 and 100 mrem/yr in actual cleanup levels, he said. An earlier version of the NRC standard proposed in 1994 met EPA's safety criteria and won the agency's support. But when NRC released a revised version April 1, EPA cried foul. In her statement to NRC, Trovato repeated EPA Administrator Carol Browner's warning expressed in a Feb. 17 letter, which said that EPA may keep NRC sites under Superfund authority. In the past, EPA had exempted NRC sites from the Superfund National Priority List with the understanding that NRC would clean the sites to levels EPA considered safe "We agree with NRC's position: There is no basis for the standard being 15 mrem/yr. It is not costeffective," said a DOE official participating in the discussions with EPA. "We think it should be 25 or 30 mrem/yr." The official said DOE also agrees with NRC's position that groundwater should not be considered under a separate standard. DOE will likely adopt the provisions of whatever NRC finally decides on, according to the official, who predicted that EPA's claim that it will put NRC sites under Superfund is not likely to happen "I don't think Congress or anyone else could stand the costs " the official said. —VINCENT LECLAIR
