HARVARD University Press recently published a book on risk regulation written by Stephen Breyer, chief judge of the U.S. Court of Appeals, First Circuit. Breyer argued that "the resources available to combat health risks are not limitless." He is exactly right. We maximize health and environmental quality by investing our money and efforts where the payoffs are highest.

It makes good sense to prioritize environmental protection. Unfortunately, good sense is conspicuously absent in current efforts to ban the use of chlorine. Greenpeace calls for a "chlorine-free society." Support also comes from other environmental organizations. George Coling of the Sierra Club states ". . . the debate is no longer whether to phase out these chemicals, but how" and Tim Eder, of the National Wildlife Federation notes, "When it comes to (these chemicals) you don't make them, produce them, or dispose of them . . . you just get rid of them!" We should be wary of their claims, for they suggest political opportunism, not sound science.

Greenpeace and its allies argue that chlorine and all organochlorines (i.e. compounds containing chlorine) threaten wildlife and people. They see an outright ban as the quickest and most effective way to improve environmental quality. Further, they claim that a "chlorine-free society" is achievable at modest economic cost. None of these claims are accurate.

Their first mistake is failing to distinguish among chlorinated compounds. A rigorous toxicology analysis composed by CanTox, a group of consultants in toxicology, health and environmental sciences, convincingly argues that the mere presence of chlorine does not render a compound carcinogenic. Assuming a substance is harmful merely because it contains chlorine is akin to assuming water is flammable simply because it contains hydrogen, a highly flammable element. Different compounds with the same elements often have very different properties.

Clearly, certain chlorinated substances, such as PCBs, DDT and dioxin, do harm wildlife at sufficiently high concentrations. However, PCBs and DDT were banned years ago and today dioxin emissions are kept to virtually undetectable levels. The point is this: Regulations should target specific substances whose environmental harm has been clearly demonstrated through rigorous scientific studies. The ad hoc reasoning used by Greenpeace and others is no substitute for careful risk analysis.

In addition, it's hard to tell if a chemical "causes harm." Harm varies with the extent of exposure and disappears entirely below certain threshold doses. In the Great Lakes, bald eagles, double-crested cormorants and other predator bird populations rebounded as DDT and PCBs were phased out and emission regulations reduced dioxin concentrations. Moreover, at the concentrations typically found in our environment, no organochlorines seem to cause identifiable human health problems.

Industrial uses aside, it is worth remembering that until chlorination became widespread, dirty water was the most serious public health problem, spreading cholera, typhoid fever and dysentery. Contaminated water supplies still kill 25,000 children a day in the Third World. The substitutes Greenpeace favors are more costly and much less effective at maintaining water purity.

Will chlorine substitutes be safer than chlorine? No one can be certain. But, we have an enormous amount of practical experience using and controlling chlorine - experience that does not exist for many substitutes and cannot exist for many innovations. Past experience indicates that new risks will appear once the substitutes are used regularly. Thus, Greenpeace presents us with a false choice - the danger of chlorines or the safety of substitutes. Chlorines are not nearly as dangerous as they portray and substitutes are unlikely to be as safe as they claim.

A chlorine ban also implies substantial economic costs. For example, pulp and paper manufacturers often use chlorine to bleach wood pulp to create high quality paper. Switching to chlorine-free processes (i.e. "totally chlorine-free bleaching"), would require extensive reconstruction of many mills at a cost of roughly $9.4 billion. The switch would cost an additional $2.4 billion per year because chlorine-free production is a less effective and less well-known method of manufacturing. The cost across all industries of a chlorine-free society, given current technology, would approach $91 billion annually.

The EPA has proposed a regulation that "only" eliminates the use of elemental chlorine in pulp and paper manufacture. Chlorine compounds such as chlorine dioxide (ClO) are permitted. This is the mildest response we could expect from an agency where politics often trumps science.

Ultimately, the effort to ban chlorine is not a simple struggle between greedy industries and good, public-spirited environmentalists. Alleged defenders of the public interest reap money and power by advocating and enforcing regulations. If successful, they often divert time, money and personnel from genuine and important environmental risks. This is the social cost of crisis entrepreneurship.

Industrial chemicals are produced for beneficial public purposes, not for corporate whim. Although we should insist that these chemicals be managed in an environmentally responsible manner, we should also be vigilant toward those who amplify and exploit public concerns and reap private gains. No one has a monopoly on virtue or knowledge.