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http://www.nytimes.com/2002/08/20/health/20BROD.html

In a World of Hazards, Worries Are Often Misplaced

By JANE E. BRODY

pared from worry about whether they will have enough to eat today or a roof over their heads tomorrow, most Americans have the luxury of worrying about the hazards that may be lurking in their air, water and food as a result of all this progress and affluence.

We are healthier, live longer, have more sources of pleasure and convenience and more regulations of industrial and agricultural production than ever, but we are also more worried about the costs to our health of environmental contaminants.

This is not to say there is nothing to worry about. In an ideal world, progress would result only in benefits, no risks. In an ideal world, we would be able to produce, organically and inexpensively, all the food we need and the food our importers rely on. In an ideal world, manufacturing would leave no residues in air, water or soil, and people would be smart and disciplined enough to resist exposure to health-robbing substances like tobacco and consistent about using protective devices like seat belts, helmets and condoms.

But this is not and never will be an ideal world, so bad things will occasionally happen. Regulations cannot control every risk. Besides, every regulation has a price. The millions or billions spent in compliance and enforcement might be better used in ways that would save many more lives, and sometimes the cost is not worth the potential benefit. I say "potential" because in many cases, the risks involved are only hypothetical, extrapolations from studies in laboratory animals that may have little or no bearing on people.

For example, despite widespread belief and laboratory studies in rats that link pollution to breast cancer on Long Island, this month an $8 million federal study found no evidence that environmental contamination from pesticides and industrial chemicals was responsible.

Why People Worry

"People are scared about environmental dangers," noted Dr. Glenn Swogger Jr., a psychiatrist in Topeka, Kan. "Being scared affects their ability to think realistically and use good judgment." Underlying these fears, he believes, are uncertainty about the effects of exposures to certain substances, a tendency to overreact and seek scapegoats in stressful situations, guilt about our affluence and an unspoken wish to return to a simpler and purer world.

Experts in risk perception say people who become agitated about real or potential risks are influenced by a number of "outrage" factors. Prominent among them is control. Is the risk voluntarily assumed or imposed by others? A woman I know who eats only organically grown food enjoys rock climbing, skiing and whitewater rafting, sports far riskier than all the chemical fertilizers, pesticides and antibiotics combined. Likewise, does it make sense for smokers to worry about pollution from a nearby factory?

In short, too often, the risks people worry most about are out of proportion to the actual dangers involved.

Next is the fairness factor. Is there a benefit to the consumer, or are consumers assuming risks resulting from benefits gained only by the manufacturer? A classic example is toxic waste dumped on a community. Or, if there are some consumer benefits, are they out of proportion to the risks? One example is the use of antibiotics in animal production, a process that has led to the spread of antibiotic-resistant bacteria.

Is the hazard natural or caused by people? Although there was a brief flurry of concern about radon, which emanates naturally from soil and rock, perpetual and far more intense concern arises over radioactivity from mine tailings and nuclear power plants. Yet the known cost to lives from other energy sources, including solar power, gas and oil, still far exceeds that associated with nuclear power.

How new or familiar is the risk? People worry much more about possible accidents caused by new technologies than about ones they have known about all their lives. Traditional plant-breeding techniques have resulted in no protests. But the introduction of genetically modified foods has prompted some people to pay premium prices for foods said to be free of any genetic manipulation, even if it results in more wholesome products.

Is there potential for a catastrophe? Consumers have repeatedly ranked nuclear power as the No. 1 hazard among more than two dozen activities and technologies, including smoking and handguns. Many people are far more frightened of air travel, especially after a plane crash, than they are of driving, which, mile for mile, presents a far greater risk.

Facts to Consider

It is not possible to anticipate, regulate and control every risk. Priorities must be assigned for risk management, with time and money devoted to those hazards best established and most likely to cause the most harm.

Not every regulation is a good investment. For example, for each premature death averted, the regulation that lists petroleum refining sludge as a hazardous waste costs $27.6 million while the rule that does the same for wood preserving chemicals costs $5.7 trillion per death avoided, according to estimates from the Office of Management and Budget.

The asbestos ban, at $110.7 million per life saved, was a bargain compared with the exposure limits placed on formaldehyde, which cost an estimated $86.2 billion per death averted.

Animal tests that result in cancer caused by a suspect substance do not necessarily apply to people. Half of all chemicals that have been tested have caused cancer in one or another experimental animal, but not always in all species or strains tested or even in both sexes. Often animal strains genetically susceptible to certain cancers are chosen for these tests. When very large doses are used in animal tests, the result is often toxicity and inflammation, which itself can cause cancer even if the substance is not carcinogenic.

A cardinal rule in toxicology is "the dose makes the poison." You can eat a dozen carrots at once with no ill effect, but 400 carrots could kill you. Animal studies rarely reveal the possible effects, or safety, of long-term exposure to the kinds of low doses people may experience.

Keep in mind that we all have livers, which accrue and detoxify small amounts of hazardous substances. Another limitation of animal tests is their usual failure to detect risks that may result from interactions between two or more otherwise innocuous substances.

Remember, too, that "natural" is not necessarily safer, and just because something is manufactured does not make it a potential hazard. Nature is hardly benign. Arsenic, hemlock and, despite its current medical applications, botulism toxin are wholly natural but also deadly.

For helpful, detailed discussions of how best to consider environmental threats, consult the new book "How Much Risk? A Guide to Understanding Environmental Health Hazards" (Oxford University Press) by Inge F. Goldstein and Martin Goldstein, who explain how controversies are investigated and why scientists sometimes disagree and fail to find definitive answers.

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