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Paracelsus to Parascience:
The Environmental Cancer Distraction

by Bruce N. Ames and Lois Swirsky Gold
September 7, 1999

4. Damage by Distraction : Regulating Low Hypothetical Risks

Synthetic, hormonally active agents have become an environmental issue. Hormonal factors are important in cancer [43;44]. The 1996 book, Our Stolen Future [74], claims that traces of synthetic chemicals, such as pesticides with weak hormonal activity, may contribute to cancer and reduce sperm counts. The book ignores the fact that our normal diet contains natural chemicals that have estrogenic activity millions of times higher than that due to the traces of synthetic estrogenic chemicals [75;76] and that lifestyle factors can markedly change the levels of endogenous hormones. The low levels of human exposure to residues of industrial chemicals are toxicologically implausible as a significant cause of cancer or reproductive abnormalities, especially when compared to the natural background [75-78]. In addition, it has not been shown convincingly that sperm counts are declining [79-81], and even if they were, there are many more likely causes such as smoking and diet.

Because there is no risk-free world and resources are limited, society must set priorities based on cost-effectiveness in order to save the most lives [82;83]. The EPA projected in 1991 that the cost to society of U.S. environmental regulations in 1997 would be about $140 billion per year (about 2.6% of gross national product) [84]. Most of this cost is to the private sector. Several economic analyses by others have concluded that current expenditures are not cost-effective; that is, resources are not being utilized so as to save the most lives per dollar. One estimate is that the U.S. could prevent 60,000 deaths per year by redirecting the same dollar resources to more cost-effective programs [85]. For example, the median toxin control program costs 146 times more per year of life saved than the median medical intervention program [85]. The true difference is likely to be greater, because cancer risk estimates for toxin-control programs are worst-case, hypothetical estimates, and the true risks at low dose are often likely to be zero [35;37;46]. Rules on air and water pollution are necessary (e.g., it was a public health advance to phase lead out of gasoline) and clearly, cancer prevention is not the only reason for regulations. However, worst-case assumptions in risk assessment represent a policy decision, not a scientific one, and they confuse attempts to allocate money effectively for public health.

Regulatory efforts to reduce low-level human exposures to synthetic chemicals because they are rodent carcinogens are expensive; they aim to eliminate minuscule concentrations that now can be measured with improved techniques. These efforts are distractions from the major task of improving public health through increasing scientific understanding about how to prevent cancer (e.g., what aspects of diet are important), increasing public understanding of how lifestyle influences health, and improving our ability to help individuals alter their lifestyles.

Why has the government focused on minor hypothetical risks at huge cost? A recent article in The Economist [86] had a fairly harsh judgment:

Predictions of ecological doom, including recent ones, have such a terrible track record that people should take them with pinches of salt instead of lapping them up with relish. For reasons of their own, pressure groups, journalists and fameseekers will no doubt continue to peddle ecological catastrophes at an undiminishing speed…. Environmentalists are quick to accuse their opponents in business of having vested interests. But their own incomes, their fame and their very existence can depend on supporting the most alarming versions of every environmental scare. 'The whole aim of practical politics' said H.L. Mencken, 'is to keep the populace alarmed — and hence clamorous to be led to safety — by menacing it with a series of hobgoblins, all of them imaginary'. Mencken's forecast, at least, appears to have been correct.

Aaron Wildavsky discusses worst-case risk assessment in his book But Is It True: A Citizen's Guide to Environmental Health and Safety Issues [87].

We should be guided by the probability and extent of harm, not by its mere possibility. The search for possibilities is endless and it trivializes the subject. There is bound to be great diversion of resources without reducing substantial sources of harm. Consternation is created but health is not enhanced…. Weak causes are likely to have weak effects. Our search should be for strong causes with palpable effects, like cigarette smoking. They are easier to find and their effects are much more important to control…. The past necessity of proving harm has been replaced by a reversal of causality: now the individuals and businesses must prove that they will do no harm. My objection to this… is profound: our liberties are curbed and our health is harmed.

Article reprinted from Mutation Research Frontiers, 7 September 1999

Revised April 23, 2015