cerned with models or procedures for assessing risks from exposure to environmental carcinogens. On the contrary, our paper is not concerned with risk assessment . Rather, it is concerned only with regulation (control) of risk. That is, our p a p e r lays out a proposed framework by which regulatory au- thorities, given estimates of risk from exposure to any environmen- tal carcinogens, would decide on appropriate actions to reduce risks to the public. Our proposal does not depend in any way on methods for assessing risk. To be sure, we sup- port the use of scientifically valid methods for risk assessment, but our proposal accommodates any methods or assumptions for esti- mating carcinogenic risk, be they valid or not. Weisburger apparently has not understood the distinction between assessing and regulating (controlling) risk. Thus, it would be more appropriate to direct his com- ments at agencies, such as EPA, which develop policies for risk as- sessment.

We would also comment briefly on three other points. First, Weis- burger asserts that we utilize “math- ematical formulations . . , to deter- mine acceptable levels of exposure” (first paragraph, second sentence). We are not sure what this means, bu t we d id not use any kind of mathematical model to determine acceptable levels of exposure (risk). All we did is propose levels of de mani fes t i s and d e m i n i m i s risks based primarily on considerations of regulatory precedents and, sec- ondarily, on estimated risks from naturally occurring carcinogens. Thus, the risk levels defining our proposed regulatory framework rep- resent subjective judgments, not de- terminations using mathematical formulations.

Second, in this same sentence. Weisburger refers to “as low as rea- sonably achievable (ALARA)” as a “newer concept.” Again, we are not sure what this means, but we note that the ALARA concept has been a fundamental aspect of radiation pro- tection principles for nearly 40 years ( 2 ) and was often applied in radia- tion protection practices long before then (2 ) . Perhaps explicit recognition of the ALARA concept is relatively new in regard to protection princi- ples for other carcinogens.

Finally, in the fourth paragraph, Weisburger appears to question use of the ALARA concept when there may be a “practical” threshold for effects from genotoxic carcinogens.

We presume that “practical no- effect levels” refer to risks that would be too low to be observed and associated with exposures in an epidemiological s tudy. We hope this will be the case for almost all exposures to environmental carcin- ogens. However, it is surely proper for regulatory authorities to take ac- tion towards risk (exposure) reduc- tion at levels below which effects would be observed, and use of the ALARA concept for this purpose is reasonable.

References (1) “Permissible Dose from External

Sources of Ionizing Radiation”; Na- tional Council on Radiation Protec- tion and Measurements: IVashington, DC, 1954; Report No. 17.

(2) Taylor, L. S . Health Phys. 1981, 42 ,

Based on work performed at Oak Ridge National Laboratory, managed for the U.S. Department of Energy under con- tract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.

227-32.

David C. Kocher Health and Safety Research Division

Oak Ridge National Laboratory Oak Ridge, TN 37831

F. Owen Hoffman Environmental Sciences Division

Oak Ridge National Laboratory Oak Ridge, TN 37831

Nuclear power plants Dear Sir: In ES&T (Oct. 1991, p. 1682), Alan Newman reported on “An International View of Nuclear Power Plants.” The article is sum- marized by ESGT as: “Nuclear power is viewed worldwide as a vi- able technology.”

In my view, this article gives an incorrect perspective of the situa- tion. Large parts of the public in Eu- rope, as well as a number of govern- m e n t s , are unwi l l ing to accept enlargement of nuclear capacity in their countries. This can be illus- trated by comparing a quotation from the ES&T article with corre- sponding quotations from the re- cent overview of the International Energy Agency (IEA) on Climate Change Policy Initiatives, update of 20 November 1991.

Newman writes: “Despite the op- position of groups like Greenpeace, public opinion in European coun- tries seems to favor nuclear power. In 1990 Swiss voters rejected an initia- tive to close down that country’s five nuclear power plants, and this year Sweden’s Parliament abandoned a 1988 decision to decommission two nuclear plants in 1995-96.”

The IEA in their document on Switzerland mentioned that: “In the referendum in September 1990, a ten-year (and in fact even longer) moratorium regarding the licensing of new nuclear production facilities was approved. However, a gradual phase-out of nuclear energy was re- jected. According to the federal gov- ernment, the construction of fossil- fueled power plants or additional long-term contracts for electricity imports should be avoided. Priority is therefore given to the efficient use of energy, including electricity. Af- ter the turn of the century, the ques- tion whether to renew, extend, or phase-out nuclear capacities will arise again.”

The IEA document on Sweden mentioned: “In February 1991, the Energy Policy Bill, based on the in- ter-party agreement [i.e., between the Social Democrats, the Liberal Party, and the Center Party] was presented to Parliament. According to the agreement, the time at which the nuclear phase-out can begin and the rate at which it will proceed, will depend on the results of elec- tricity conservation measures, on the supply of electricity from envi- ronmentally acceptable sources and on whether internationally compet- itive electricity prices can be main- tained. The 1980 parliamentary de- cision to phase-out nuclear power by 2010 has not been reconsid- ered.”

Clearly, the decisions to keep open existing nuclear power plants are taken against a background of severe distrust on nuclear power. Similar examples could be given from other parts of Europe.

In a more objective article on the s ta tus a n d prospects of nuclear power, ES&T might further have mentioned that the Japanese gov- ernment has been unable to secure so far the necessary new sites for nuclear power plants due to resis- tance at local levels, that the govern- ment of the United Kingdom was unable to sell its nuclear power plants to private investors. and that Germany provides some examples of “economic catastrophes” in the nuclear field, e.g., at Kalkar.

Finally, I wish that at least the re- ports on nuclear power could be trusted.

Jacob Swager Head o f the Climate Change Division

Ministry of Housing, Physical Planning and Environment of the Netherlands

Postbus 450 2260 MB Leidschendam

The Netherlands

846 Environ. Sci. Technol., Vol. 26, No. 5, 1992