SHOULD EVERYTHING BE LABELED?

When the worry is focused on phantom or insignificant risks, it diverts personal attention from risks that can be reduced.36

Milton Russell, former Assistant Administrator, Environmental Protection Agency and Professor of Economics at University of Tennessee.

Everyone knows that if you spend all of your time on trivia and don't focus on important problems, it is completely counterproductive. If we devote too much of our attention to traces of pollution and away from important public health concerns . . . we do not improve public health, and the important hazards are lost in the confusion.37

Bruce N. Ames, Chairman of the Department of Biochemistry at the University of California at Berkeley

It will be very difficult to convey information to people in a meaningful fashion about low-probability risks. Perhaps the greatest danger from any risk-communication effort is that instead of informing people these programs will serve to unduly alarm them and cause overreaction.38

W. Kip Viscusi, George G. Allen Professor of Economics at Duke University

Making False Assumptions About Science. Proposition 65 is not a law with a few errors that can be corrected by amendment or patchwork reform. It is a law fundamentally flawed by faulty assumptions about the nature and role of science. Among other unstated assumptions, Proposition 65 is based on the beliefs that (1) we are exposed to only a few carcinogenic substances, (2) we have reliable means of identifying those substances; and (3) we can eliminate our exposure to those substances with minimal discomfort. As we shall see in the next section, all of these beliefs are wrong.

Nothing frightens the voting public more, or brings faster action from elected officials, than the potential risk of cancer. This is not surprising. In the political arena, expressions of outrage are easy and those who demand action expect others to pay the costs of that action. Often, big corporations or other faceless entities are thought to be picking up the tab for politically established regulations.

The same citizens, however, act quite differently in accepting and avoiding risk when they control the degree of risk through their own behavior, and when they bear the direct costs, and reap the direct benefits of their actions. Epidemiologists estimate that at least 70 percent of human cancer is in principle avoidable through behavioral changes. These facts are widely known, and have been broadly disseminated.39 Yet they have not caused undue alarm and have induced slow and moderate changes in personal living habits.

Individuals also have little trouble remaining calm and careful in the face of newly revealed dangers such as the natural cancer risk from radon gas in their homes, despite the fact that this danger can be considerable. As many as one million homes are believed to be generating radon decay exposure levels in excess of the exposure received by uranium miners, and as much as 10 percent of lung cancer in the United States has been tentatively attributed to radon pollution in houses.40 Such revelations have not caused panic, but have instead created a market for detection devices, allowing people to take cost-effective actions to reduce their radon exposure.

Risk avoidance in the political sector is another matter. As we have seen, fear of cancer has been the driving force behind the passage of Proposition 65 and behind other state and federal legislation, including the banning of DDT and the creation of Superfund.

Almost every statement about the risk of cancer is a hypothesis -- not a fact that has been scientifically proved. Among the chemicals tested in rodents, a high percentage have been found to cause cancer when administered in very high doses. Yet it is not clear what inference we can draw from these experiments about the risk to human beings, especially at very low exposure levels. The International Agency for Research on Cancer (IARC) lists only 26 chemicals or groups of chemicals as showing definite evidence of human carcinogenicity.42 Even for these 26 chemicals, very little is known about the mechanism by which they cause cancer.

Two things seem certain. First, we cannot avoid exposure to carcinogenic substances. Carcinogens are present in almost all the food we eat and almost all the air we breathe, and even occur naturally in our body. Second, evolution must have endowed us with biological defenses against carcinogens or we could not have survived constant, daily exposure to them.

What follows is a brief summary of current knowledge about the causes and risks of cancer in an attempt to put current public policy debates into perspective.

Cancer Rates are Falling, Not Soaring. A popular belief is that an epidemic of cancer is sweeping the modern world as a result of increasing chemical inputs into the human body. This belief is false. The scientific literature reveals many warnings of potential dangers. New chemicals could of course be deadly, and the effects on humans might not show up for many years. Yet the increasing production of chemicals and human exposure to them has gone on for decades. In "The Causes of Cancer," a comprehensive survey sponsored by the Office of Technology Assessment of the Congress and published in the Journal of the National Cancer Institute, Richard Doll and Richard Peto conclude that except for the increase in lung cancer and skin cancer, "examination of the trends in American mortality from cancer over the last decade provides no reason to suppose that any major new hazards were introduced in the preceding decades."43 Over the decade 1974 to 1983,

• Stomach cancer fell 20 percent, cancer of the cervix-uterus fell 30 percent, and cancer of the ovary fell eight percent.

• The only cancer rates that clearly increased were lung cancer, up 15 percent for men, 72 percent for women, and thought to be caused by smoking, and skin cancer, up 20 percent, and thought to be caused by sunlight exposure.

Exposure to Carcinogens is Unavoidable. Carcinogens are everywhere. Without any help from man, carcinogens are naturally present in almost every meal. They are present in mushrooms, parsley, basil, celery, cola, wine, beer, mustard, peanut butter, bread, lima beans and hundreds of other everyday foods.

Human beings also produce carcinogens through everyday activities. Baking bread, browning meat, cooking bacon and eggs -- all of these activities cause chemical reactions that produce carcinogens. Allowing a sliced apple to become slightly brown involves an oxidation reaction that produces carcinogenic peroxides. Carcinogens also occur naturally inside the human body. For example,

• Isotopes of potassium, produced naturally in the body, expose us to natural radiation.

• Our normal metabolism produces carcinogens such as hydrogen peroxide and other reactive forms of oxygen.

• Many common metal salts naturally present in our bodies are carcinogenic, including lead, cadmium, beryllium, nickel, chromium, selenium, and arsenic.

Arsenic is not only carcinogenic, it is a well-known deadly poison in large quantities. Yet in small quantities it is apparently essential to life. Like the other carcinogens listed above, the risk of cancer from arsenic found in our bodies is believed by most experts to be trivial. But even if the risk is not trivial, it should be clear that if we are to eliminate death by cancer we will have to find a "cure" for cancer. We will not be able to do it by avoiding carcinogens.

Most Man-Made Pollutants Pose Insignificant Cancer Risks When Compared to the Background of Natural Carcinogens. A widespread fear is that we are being subjected to ever-increasing risks of cancer because of man-made chemicals introduced into the air, food and water. Yet the weight of the evidence indicate that man-made pollution poses very small cancer risks when compared with natural carcinogens to which we are exposed:

• Although there is increasing public concern over the cancer risk from pesticide residues in our food, the amount of carcinogenic pesticides consumed in a day is one-twentieth of the amount of natural carcinogens in one cup of coffee.44

• Although there is increasing concern over the cancer risk from polluted air, the amount of carcinogens in the browned and burned food we eat in a day -- the carcinogens produced by cooking -- is several hundred times greater than the amount of carcinogens inhaled by breathing severely polluted air.45

In general, the cancer risks from pesticides in food and from additives in our diet are trivial in comparison with the quantities of natural carcinogens we routinely consume. At the microscopic level, nature is a virtual carcinogenic factory.46

• Natural carcinogens and other toxins are present in all plants and serve to protect plants against fungi, insects, and animal predators.

• These natural toxins make up from five to 10 percent of a plant's dry weight.

• Because of their presence, we ingest in a normal diet 10,000 times more natural toxins than we ingest of man-made pesticide residues.

An estimate of the relative risk from substances that may cause cancer is presented in Table II. This table, taken from a survey article by Bruce Ames and his colleagues, ranks relative cancer risks based on experiments with rodents and ordinary human exposure levels.47 In each case, the risk has been normalized for comparison with ordinary tap water, which carries a tiny risk of cancer from the chloroform which is present in chlorinated water. As the table shows,

• The risk from consuming all major pesticides (EDB, PCBs, DDE/DDT) in a typical diet is 30 times less than the risk from drinking ordinary tap water.

• The risk from consuming pesticides is 100 times less than the risk from natural carcinogens in a raw mushroom, 400 times less than the risk from natural carcinogens in a typical sandwich, and thousands of times less than from the natural carcinogens in cola, wine, or beer.

• The risk of the food additive saccharin in a diet cola is 45 times less than the risk associated with the natural carcinogen formaldehyde, found in the same drink.

It is important to note that all of the items listed in Table II, in the quantities indicated, are believed to create a trivial risk for human beings. These items are presented here only to help establish perspective.

There was a time, not long ago, when it was widely believed that most foods we consumed and most chemical-containing products we used were completely safe. That has changed, in part because of the ability of scientists to detect trace elements of chemicals in amounts as small as one part per billion and even one part per trillion. Scientists also have the ability to test these chemicals on rodents in large doses. For example, in one test on a decaffeinating agent for coffee, rodents were given the equivalent of 12 million cups a day.48 Of all known chemicals, only a tiny handful have been tested. For example,49

• There have been about 392 tests of chemicals in both rats and mice.

• There are more than seven million man-made chemical compounds listed in the American Chemical Society's registry and more than 63,000 are in current use.

Of the chemicals tested, a surprisingly high percentage have proved to be carcinogenic at some dosage level -- 60 percent of man-made chemicals tested and 45 percent of natural chemicals. Moreover, there is every reason to believe that further tests will indict literally thousands of additional synthetic and natural chemicals as rodent carcinogens.

What do these tests mean? That's not clear. For example, almost half of the tests that produced cancer in mice failed to do so in rats, or vice versa. Since rats and mice are biologically similar and both are dissimilar from humans, extrapolating from these rodent experiments to statements about risks for people is a considerable leap. In addition, it is not clear what we can infer from high-dosage rodent experiments about the risk faced by humans when exposed to low dosages.50

Despite the hundreds of experiments conducted and the enormous amounts of money spent on such tests (from $250,000 to $500,000 per experiment), we still know very little about how cancer is caused. Even cigarette smoking, the most heavily studied of all carcinogenic risks, still remains much of a mystery. For example, two-thirds of all cigarette smokers do not get lung cancer and 25 percent of people who do get lung cancer do not get it from smoking. No one knows why.

In general, the risks of cancer from man-made chemicals are far smaller than one might gather from the impassioned rhetoric of some environmentalists, or even from news reports which fail to distinguish between the dangers from tiny doses of exposure to humans on the one hand, and those from megadoses administered to rats on the other. A fundamental principle of toxicology is that "the dose makes the poison." Substances such as vitamins and minerals which are essential to human life in small doses are, at the same time, deadly in large doses. Also, what is a deadly poison to one species may be quite safe for another, even in the same dosage relative to body size. Rodents, for example, vary in their sensitivity to certain toxins by a factor of many thousands.

These facts should make clear that when a chemical is "carcinogenic," it may either be deadly in doses likely to be encountered by humans, or it may be quite safe in those doses. Even if it is dangerous to humans, the chemical may or may not be worth avoiding, depending on the benefits of using it. If the benefits are large and the substance hard to replace, the danger may be smaller than the best available alternative.

Relative Risk 1	Source/Daily Human Exposure	Carcinogen
1.0	Tap Water - one liter	Chloroform
4.0	Well Water - one liter (worst well in Silicon Valley)	Trichloroethylene
Risks Created by Mother Nature
Relative Risk	Source/Daily Human Exposure	Carcinogen
30.0	Peanut butter -- one sandwich	Aflatoxin
100.0	Mushroom - one, raw	Hydrazines, etc.
2,800.0	Beer -- 12 oz.	Ethyl alcohol
4,700.0	Wine -- one glass	Ethyl alcohol
0.3	Coffee -- one cup	Hydrogen peroxide
30.0	Comfrey herbal tea -- one cup	Symphytine
400.0	Bread -- two slices	Formaldehyde
2,700.0	Cola -- one	Formaldehyde
90.0	Shrimp -- 100 g.	Formaldehyde
9.0	Cooked bacon -- 100 g.	Dimethylnitrosamine, Diethylnitrosamine
60.0	Cooked fish or squid, broiled in a gas oven -- 54 g	. Dimethylnitrosamine
70.0	Brown mustard -- 5 g	Allyl isothiocyanate
100.0	Basil -- 1g of dried leaf	Estragole
20.0	All cooked food -- average U. S. diet	Heterocyclic amines
200.0	Natural root beer -- 12 oz. (now banned)	Safrole
Food Additives and Pesticides
RelativeRisk Risk	Source/Daily Human ExposureRisk	Carcinogen
60.0	Diet Cola -- 12 oz	. Saccharin
0.4	Bread and grain products -- average U.S. diet	Ethylene dibromide
0.5	Other food with pesticides -- average U.S. diet	PCBs, DDE/DDT
Risks Around the Home
Relative Risks	Source/Daily Human Exposure	Carcinogen
604.0	Breathing air in a conventional home -- 14 hours	Formaldehyde, Benzene
2,100.0	Breathing air in a mobile home -- 14 hours	Formaldehyde
8.0	Swimming pool -- one hour (for a child)	Chloroform
Risks At Work
Relative Risks	Source/Daily Human Exposure	Carcinogen
5,800.0	Breathing air at work -- U. S. average	Formaldehyde
Commonly Used Drugs
Relative Risks	Source/Daily Human Exposure	Carcinogen
16,000.0	Sleeping pill (Phenobarbital) -- 60 mg.	Phenobarbital
300.0	Pain Relief pill (Phenacetin) -- 300 mg.	Phenacetin

Note: The items listed above are for illustrative purposes only, and are not intended as a guide for safe behavior. Relative risk is based on experiments subjecting rodents to very high dosages. The risk of these items to humans, in the quantities given above, is thought to be trivial. Source: Bruce N. Ames, Renae Magaw, Lois Swirsky Gold, "Ranking Possible Carcinogenic Hazards," Science, Vol. 236, April 17, 1987, pp. 271-236.

1 The underlying measure of risk used here is a HERP value: Human Exposure dose divided by Rodent Potency dose. The measure of rodent potency is the milligrams of substance per kilogram of rodent body weight necessary to produce cancer in one-half the rodents, given daily exposure over the rodents' lifetime. Human exposure is measured by the daily consumption indicated in the table per kilogram of human body weight. In the table above, the HERP values have been normalized with respect to the HERP value for water. A value of 100,000 means that the human exposure dose per kilogram of weight is exactly equal to the amount of the substance per kilogram of weight necessary to produce cancer in one-half of the rodents.

How important is the risk of consuming carcinogens compared to other risks we face? Table III compares the relative risk of a number of everyday activities, indicating for each how it increases the probability of death by one in one million -- a risk level often used by federal and state governments in setting required levels of safety. As the table shows,

• The risk of getting cancer by drinking tap water for a year is less than the risk of cancer from increased exposure to cosmic radiation by making two round-trip airline flights between Los Angeles and New York City.

• The risk of getting cancer from the saccharin in 30 diet colas is equivalent to the risk of cancer from living two months in Denver.

• Virtually all the cancer risks from our diet are trivial compared to the risk of driving to work each day.

Table IV presents a number of risks from occupational, sporting, and other activities from a different perspective. Combining it with Table II, note that many voluntarily chosen human activities such as hunting, boating, and farming are hundreds of times more dangerous than consuming pesticides.

The data and scientific evidence cited above is not secret. It is available to all, in the scientific literature. Yet the legislative process at both the federal and state levels seemingly has given little weight to these facts. Instead, the outrage of citizens, uninformed about toxicology and swayed by articulate and passionate rhetoric condemning each potential danger -- usually without regard to the problems of alternative courses of action -- has led from the Love Canal tragedy to the Superfund fiasco, and from largely phantom carcinogenic chemical threats in California to Proposition 65.