It was the first of a series of potential environmental catastrophes which have popped via the news media into the public consciousness with increasing and relentless frequency. For example, attendees at a meeting of the American Chemical Society in San Francisco last August heard a University of California scientist warn that a fireproofing chemical used in large amounts in children's pajamas might cause cancer in those children. At the same meeting, scientists alerted their colleagues to the fact that some California wines were laced with large concentrations of poisonous and possibly cancer-causing arsenic, and that cancer-causing chemicals (carcinogens) were found in several commercial lawn and garden sprays.
As each of these new and potentially deadly encroachments on our health and environment works its way up the scare scale, it supplants--in the public's mind at least--other crises that have emerged in the last twenty years or so. In 1964, the discovery of DDT's toxicity caused Rachel Carson's fears of a silent spring. In the early 1970s, mercury was revealed as threatening serious damage to the brains and bodies of this and future generations, and the frightening dangers of asbestos were publicly acknowledged. What about those crises of yesteryear? Can we stop worrying about them? Or are they still around, silently threatening us and our children with premature death? What, for example, ever happened to the cranberry crisis?
In retrospect, it doesn't look nearly so frightening as it did when then Secretary of Health, Education and Welfare Arthur Flemming announced that two shipments of cranberries from the states of Washington and Oregon contained possibly harmful levels of aminotriazole. Because animal tests showed that the weed killer caused thyroid cancer, he recommended that cranberries from those states be taken off the supermarket shelves. The move seemed reasonable enough from a bureaucratic and health point of view, but it left shoppers with no way of telling whether their Thanksgiving cranberry sauce originated in Oregon or in a "safe" state, such as New Jersey. Then, just three days before the holiday, Flemming announced that the Department of Health, Education and Welfare had developed techniques for certifying cranberry batches as good or bad. By that time, however, much of the public had decided either to abstain from cranberries until the fuss blew over or to take their chances with the risk of cancer.
The cranberry scare now seems more of a nuisance than an environmental crisis. Cranberry growers felt a slight decline in their business for several months after the aminotriazole ban, but by the following Thanksgiving, Americans had gotten over their cranberry phobia. And although the herbicide could no longer be used on food crops of any type, the growing demand for it as a weed control for roadsides, parks, and railroad rights-of-way easily offset the temporary losses experienced by aminotriazole's two manufacturers. In fact, the cranberry crisis might never have occurred if farmers in Washington and Oregon had followed the instructions on the aminotriazole bags and applied the weed killer after the berries were removed from the bushes instead of before.
Verdict: The cranberry crisis is over.
WAS RACHEL CARSON RIGHT?
Whether Rachel Carson was right when she warned about the perils of the insecticide DDT in Silent Spring has still not been completely resolved. But she might as well have been. Since her book appeared in 1962, use of DDT in this country has dwindled to a few select applications. Previously it had been sprayed indiscriminately from one end of the biosphere to the other. The series of actions against DDT, which began even before the book appeared, were based on findings that in some cases went well beyond Carson's predictions.
Unassailable evidence suggested that DDT was being carried by air, sea, and living organisms to areas as remote from the original spray site as the South Pole. The persistence of DDT, which made it so useful for the long-term control of mosquitoes in malaria areas, was also causing a long-term buildup in the fatty tissues of man and animals. The buildup started early: infants received their first taste of DDT in their mother's milk. Insects, on the other hand were developing resistance to DDT, and each time a larger killing dose was aimed at the insects in the fields, the potential threat to man and animals also increased.
Researchers soon found that virtually all terrestrial organisms had to some extent been touched by DDT. It decreased photosynthetic processes in phytoplankton and they could no longer produce enough oxygen for fish to breathe. It blocked hatching in fish and sometimes built up to lethal levels in the brains of migrating birds. DDT, by reducing the thickness of bird's eggshells, threatened the existence of ospreys, sparrowhawks, pelicans, and other birds that feed on animals contaminated with DDT.
No proof is yet available that DDT is an immediate threat to human health. A few successful suicide attempts and a number of accidental deaths have been attributed to the injection of large amounts of DDT: there have also been a few cases that indicate that large doses will cause tremors and other symptoms of nerve damage. Yet, although millions of people in malaria areas and many workers in DDT plants were exposed to relatively high concentrations of DDT for as long as twenty years, the increased exposure has apparently had no adverse health effects to date. Critics of the DDT ban, including Dr. Thomas Jukes of the University of California at Berkeley, point out that for many years some chemical plant workers were taking in a daily dose of DDT approximately 1250 times greater than what the average American was absorbing in the late sixties.
Whether DDT can or will cause cancer in man is still very difficult to pin down. Some evidence suggests that it causes tumors in rats, but probably not in other animals, including monkeys and chickens. Like other chemical carcinogens, DDT may require an incubation period of twenty years or more before the cancer it produces becomes evident. If so, those cancers may just now be starting to appear. We may NEVER know if DDT causes cancer in man, because everyone's fatty tissue contains some of the insecticide. Thus, we have no uncontaminated control population against which to measure its cancer-causing effect. Also, many of those most extensively exposed to DDT in farm and orchard were migrant workers who have now scattered beyond the reach of adequate medical follow-up.
Dr. Jukes says that the DDT boycott was chiefly an expression of "environmental chic" on the part of prosperous urban dwellers whose concern about the demise of the songbirds ignored the need for DDT among "the inarticulate majority of the world's people...who are struggling against disease and hunger. He argues that while DDT is not demonstrably harmful to human health, it has saved 5 million lives in underdeveloped areas and prevented 100 million illnesses since it was introduced in 1942. Dr. Jukes cites recent evidence from Cornell University that the thinning of eggshells was probably caused not by DDT but rather by other environmental contaminants, including mercury, or by one of the more recent worldwide pollutants, the polychlorinated biphenyls (PCBs).
The ban has not only lowered the environmental hazard associated with DDT; it has also left its mark on the manufacturers who produced it as well as on the farmers who saw it as a cheap and efficient way to kill pests and increase crop yields. Production of DDT in the United States dropped from a peak of 188 million pounds in 1963 to about 40 million pounds in 1974, and most of that is exported to malaria zones. Cotton producers, by far the largest users of DDT in this country, now complain that since they have been forced to control the boll weevil and other cotton pests with other, more expensive insecticides, cotton prices have risen and crop yields have gone down. Farm workers in California and other large agricultural areas are equally unhappy about the DDT ban because they know that the organophosphate insecticides that have replaced it are far more toxic than DDT. Although the organophosphates are quickly destroyed by rain and other environmental factors, they come from the same molecular family as the nerve gases in this country's chemical weapons stockpile. Not surprisingly, misuse of the organophosphates has sickened or killed children, spray-plane pilots, and farm workers who inadvertently absorbed them by mouth or through the skin.
In spite of those considerations, and the continuing objections to the ban by Dr. Jukes and Nobel Prize winner Norman Borlaug (of Green Revolution fame), DDT will probably never again be used except on a spot basis in the United States. That happened recently in Colorado, when the Environmental Protection Agency said the state could use DDT to eliminate an outbreak of plague-carrying rat lice. Nevertheless, each time a community decides that a quick attack with DDT is needed to wipe out an invasion of gypsy moths or other pests, it must fight its way past local environmentalists and government restrictions. On that basis, a DDT revival on a national scale is almost inconceivable.
Verdict: Rachel Carson may have been right. But while DDT's effects on human health seem negligible, its long-term effects may still be felt.
THE CYCLAMATE SCARE
Artificial "cyclamate" sweeteners were banned by the Food and Drug Administration ten years after the cranberry crisis. Before the federal proscription, cyclamates generated a $500 million-a-year industry in the United States and were being ingested at a rapid rate in diet drinks, jams, jellies, children's vitamin preparations, desserts, ice cream, canned fruits, and other products. The ban was emphatic, but the FDA ruling softened the blow by allowing supermarkets, as well as food and beverage producers, to use up their backlog of cyclamate-containing products.
The sweetener, manufactured largely by Abbott Laboratories in Chicago, had come under suspicion well before the actual ban: animal studies carried out by the FDA suggested that it caused "teratogenic" abnormalities in chick embryos similar to those observed in children of pregnant women who had been taking the tranquilizer thalidomide. In addition, evidence had accumulated that cyclamate might have long-range genetic effects, since the substance apparently damaged chromosomes in the cells of animals and human beings. What ultimately led to the ban, however, was Abbott's own report to the FDA that bladder tumors developed in rats consuming the sweetener in daily amounts equivalent to what would have been found in 500 eight-ounce bottles of a typical diet cola.
Since then, both Abbott Laboratories and independent scientists have begun to question whether the evidence was sufficient. Abbott has been asking the FDA to lift the ban since 1973, arguing that its more recent long-term studies with various laboratory animals indicate that, at reasonable intake levels, cyclamates are perfectly safe.
The company was further encouraged in February of 1976 when a careful and critical analysis of all available data, by a panel of scientists commissioned by the National Cancer Institute, concluded that "the present evidence does not establish the carcinogenicity of cyclamate or its principal metabolite cyclohexylamine." The "cyclohexylamine" alluded to studies which indicated that after the cyclamate is broken down in the body to cyclohexylamine, the latter substance might also cause cancer or other adverse effects on health.
In its critique of several inconclusive animal tests, the NCI panel noted that although the earlier Abbott studies showed bladder tumors occurring in 12 of 80 rats, cyclamate alone was not necessarily the cause. Abbott scientists fed the rats mixtures of cyclamate, cyclohexylamine, and saccharin. Saccharin was added because it was contained in Abbott's commercial cyclamate formulations. The scientists on the NCI panel also noted the absence of conclusive evidence that cyclamate caused bladder tumors in hamsters, dogs, or monkeys, or in diabetics who consumed more of the artificial sweetener than average individuals. Rats, the scientists suggested, might be especially susceptible to its effects. They did not, however, ask that the cyclamate ban be lifted, pointing out that major uncertainties remained about the possible genetic or teratogenic effects of cyclamate or cyclohexylamine.
The NCI report was strong enough in some areas and vague enough in others so that each side in the controversy interpreted it as vindication of its own position. Convinced that the FDA would finally rescind the ban, Abbott petitioned the agency again, and the company was fairly confident that the sweetener would be back on the market before the end of 1976. But, in October, the FDA formally rejected the Abbott petition on grounds that cyclamate was still not safe enough for large-scale use as a sweetener. Abbott asked for a hearing before the FDA, and will go to the courts if that doesn't work.
Not that the company's fortunes will rise or fall on the basis of what the FDA finally decides. Just before the ban, annual sales of cyclamate reached about $8.5 million, or roughly one percent of the company's business. In addition. Abbott still has a "small slice" of the 5 to 8 million pounds of cyclamate being sold in thirty other countries, where it is considered safe. In Canada, cyclamate can be sold only as a table sweetener, but in Germany and other European countries, cyclamate appears in beverages and food products, just as it did in the United States before the ban.
Verdict: The cyclamate crisis is over in the United States, and the sweetener may eventually win a clean bill of health. If the cyclamates do cause cancer or genetic defects in human beings, they are probably doing so in Germany and other countries where they are now being sold.
THE MERCURY CRISIS
In August 1976, twenty-five Indians who fished in the James Bay area of Quebec showed definite signs of mercury poisoning, proof that the mercury crisis of the early 1970s is still with us. It first made itself known in North America when a chemist from the University of Western Ontario found that fish from Lake St. Clair (near Detroit) contained mercury levels close to the levels found in fish eaten by mercury-poisoned residents of the Japanese villages of Minimata and Niigata. The mercury in the Japanese incident was a byproduct of a plastics plant, and before the source was cut off, scores of Japanese men, women, and children died, became insane, or developed neurological symptoms of mercury poisoning. The same findings in fish and other foodstuffs from lakes, rivers, and farms throughout the United States prompted quick controls on mercury pollution in those areas and, in some cases, fishing bans in the affected waters. The mercury crisis also inspired federal regulations on the mercury content of tuna and swordfish, both of which were found to contain abnormally high levels of the metal.
As the mercury crisis has disappeared from the headlines, earlier control measures seem to have been forgotten or deliberately overlooked. Most California fish markets sell swordfish containing higher than permissible levels of mercury. The government has moved with only limited success against the use of agricultural fungicides containing mercury, and in March 1976, the Environmental Protection Agency backed off from banning use of such fungicides in paints. Part of their reason was that the three manufacturers involved said that the ban would cost the jobs of forty employees and wipe out expected sales of $4 million in 1976.
But even if stringent controls on all sources of mercury pollution were strictly enforced, many scientists suspect that mercury already in the water supply will remain a threat for years to come. The reason is that when "inorganic" mercury salts enter a lake or river, they sink to the bottom, where they are slowly converted by microbial action into the "organic" methyl mercury form which killed scores of Japanese twenty years ago and poisoned the Quebec Indians last year. Once converted to the organic methyl mercury form, the poisons move up the food chain from phytoplankton to fish to man. That could mean that microbes will be converting the 200,000 pounds of mercury now resting on the bottom of Lake St. Clair alone into methyl mercury for the next 5000 years. And the mercury now there cannot be easily removed, since dredging operations would disseminate it more widely.
Verdict: The mercury crisis may be forgotten, but it is not over.
THE OZONE LAYER CONTROVERSY
"We can no longer be easily described as environmental kooks," said Dr. Sherwood Rowland last fall, in response to a series of scientific findings and federal actions that seemed to vindicate his earlier warning that the stratospheric layer of ozone which normally shields us from harmful solar radiation was gradually being eaten away by the aerosol propellants known as chlorofluorocarbons.
Scientific backing for the controversial prediction that Dr. Rowland and his colleague Dr. Mario Molina made more than two years ago on purely theoretical grounds came last August from a committee appointed by the National Academy of Sciences to study the problem. Their report was solved within weeks by a statement from the Food and Drug Administration which proposed an "orderly phaseout of all non-essential uses of chlorofluorocarbon propellants in food, drug and cosmetic products." Soon after that, the Environmental Protection Agency called for a similar ban on pesticides which contained chlorofluorocarbon propellants.
The ozone layer controversy really began when Rowland and Molina, chemists at the University of California at Irvine, learned from other scientists that most chlorofluorocarbons produced so far are ending up in the atmosphere and will probably stay there for quite some time. That information set them to wondering what would happen if the relatively inert substances worked their way up into the ozone-rich stratosphere--some twenty miles above the earth--where they would be subject to attack by the sun's ultraviolet radiation. Rowland and Molina were particularly interested in the fate of chlorofluorocarbon-11 and chlorofluorocarbon-12, both of which are used as refrigerants and as the gaseous propellants for spray-can products.
Rowland and Molina were startled by the implications of their theoretical calculations, which indicated that when a chlorofluorocarbon molecule reaches the stratosphere and is attacked by ultraviolet radiation, it is broken down chemically and releases a chlorine atom. That in turn reacts with a single ozone molecule (composed of three oxygen atoms), setting off a chain reaction which doesn't stop until hundreds of thousands of other ozone molecules are destroyed.
Rowland and Molina theorized that if chlorofluorocarbon production were maintained at 1974 levels (about half a million tons a year), it would deplete the ozone layer from 7 to 14 percent by the year 2000. And if that trend should continue, the added ultraviolet radiation that got through to the earth's surface would destroy crops and probably interfere with world weather patterns. In addition, solid biological evidence suggested that an ozone depletion on that scale could increase skin cancer incidence among light-skinned individuals by 14 to 28 percent.
After the University of California at Irvine calculations appeared in Nature magazine in the summer of 1974, manufacturers of aerosols and aerosol products responded vigorously. They wouldn't hear of a chlorofluorocarbon ban, as Rowland had suggested, because the calculations were nothing more than a paper exercise in the industry's eyes. Further, they said, no real evidence had been offered that the heavy chlorofluorocarbon molecules ever reached the stratosphere, or, if they did, that they were destroying the ozone layer.
Industry's concern was understandable. In 1974, the chlorofluorocarbon and satellite industries employed more than a million people, and if the calculations of the two chemists were correct they could seriously wound an industry that contributed an estimated $100 billion to the economy. Corporate giants, such as E. I. duPont de Nemours & Company, which sold $183 million worth of the propellants in 1974 (2.6 percent of its total sales), would undoubtedly weather the loss, but Racon, a smaller company, which derived 36 percent of its revenues from the chlorofluorocarbons, would not fare nearly as well if a ban were suddenly declared.
To counter the Rowland-Molina projections, the aerosol industry--most noticeably represented by duPont--came up with its own models of what might be happening to the chlorofluorocarbons. One alternative, now more or less debunked by laboratory findings and stratospheric measurements, proposed that after the aerosols are broken down by ultraviolet light, they react preferentially with other atmospheric components, rather than with the molecules of the ozone layer. However, after looking at all the evidence accumulated over the last two years, the NAS panel concluded that the chlorofluorocarbons were doing just about what the two California chemists predicted they would do.
The NAS committee report stopped short of recommending a ban on the aerosol propellants, suggesting that since the ozone layer would be depleted by only 0.2 percent in the next two years, and because many questions about the chemistry of the ozone layer were still unanswered, it would be safe to wait that long before implementing such a ban. However, the FDA and EPA actions, which are still subject to several months of public hearings on both sides of the question, make a ban a near certainty even before two years. Meanwhile, both government agencies call for interim warning labels on all products containing the chlorofluorocarbon propellants.
Even without the compulsions of a formal ban, a steady dropoff in chlorofluorocarbon production within the last year indicates that the industry has already been affected by what may be happening in the stratosphere. The American Can Company saw its spray can sales decline by 25 percent, while a company which made a billion valves for aerosol cans in 1975 cut production in 1976 by 40 percent. The scramble away from the chlorofluorocarbons is also evident in the trend toward, roll-on deodorants and new kinds of dispensers, including pump tops and squeeze sprays. The switchover has meant increased profits for many other companies, including the Thiokol Corporation of Newton, Pennsylvania, which recently took orders for 25 million of its new non-pressurized trigger spray cans. Recognizing that the chlorofluorocarbons were no longer good business, the S. C. Johnson Company in Racine, Wisconsin, jumped the gun on the competition and announced with full-page newspaper ads that it was switching to hydrocarbon propellants, which presumably have no effect on the ozone layer. Finally, a duPont scientist recently conceded that his company is also looking for replacements for chlorofluorocarbons, but that the two most likely candidates discovered so far are too toxic to be considered for human use.
Verdict: Look for a ban on chlorofluorocarbon aerosol propellants within two years. The detrimental effects of the millions of pounds of chlorofluorocarbons already en route to the stratosphere may not be felt for several decades.
THE ASBESTOS TIME BOMB
Lodged in the lungs of nearly everyone breathing in today's industrial world are tiny fibers of asbestos which may represent one of the most frightening health hazards yet uncovered. Based on what has been learned from studies of asbestos workers over the last fifty years, the fibers could be the harbingers of a large-scale epidemic of lung cancer and an even more devastating malignancy known as mesothelioma.
Credit for sounding the asbestos alarm in this country goes to Dr. Irving Selikoff of the Mt. Sinai School of Medicine of the City University of New York. About eight years ago, several studies carried out in this country, England, and Africa convinced him that asbestos was not as inert and biologically harmless as originally believed.
Since the 1920s, we have known that asbestos workers employed in the industry for long periods of time were dying of asbestosis, a kind of pneumonia associated with a buildup of fibers in the workers' lungs. Although asbestosis is not considered a malignant disease, the prognosis for asbestos workers began to look even worse in the 1930s. when physicians in several countries found that asbestos workers had about ten times the lung cancer risk other workers did. Lung cancer is extremely difficult to treat and is almost invariably fatal if not detected and treated at a very early stage. More bad news was yet to come. Asbestos workers were also dying of mesothelioma, a rare but deadly cancer which affects the lining surrounding the lungs and body. Until it cropped up in asbestos workers, physicians infrequently encountered the disease.
Dr. Selikoff's own recent studies of 632 asbestos workers employed for various periods between 1943 and 1974 clearly implicate asbestos as a major cause of cancer. He found that 89 of the workers died of lung cancer compared to an expected 12 deaths from the disease in the "normal" population. And in a group of 632, where NO case of mesothelioma was expected, 35 died of the disease. More significant was the fact that even though many of the workers been exposed to asbestos for periods of as little as a few months, they had apparently inhaled the seeds of cancerous conditions that flowered twenty to thirty years later. In spite of these ominous statistics, accumulated over a period of fifty years the asbestos problem is only now beginning to be taken seriously.
"I can't explain that quiet period," Dr. Selikoff says. "The industry grew fivefold, but nothing was done to warn or protect the workers. No asbestos dust counts or other precautions were taken in asbestos plants. Unfortunately, now that we are finally aware of the dangers involved, we find that instead of a small problem, we have a huge problem." What makes the asbestos problem so huge is that nearly everyone's body has been invaded by fibers from an industry which mines 3 to 4 million tons of asbestos every year. Asbestos is used in insulation for walls and furnaces, in fireproofing sprays for large skyscrapers, in floor and ceiling tiles, in automobile brake linings, in cement piping, for filtering beer and wine, and in scores of other applications.
The possibility that asbestos is contaminating people who never worked in the industry comes from studies in South Africa which clearly show that people who live near asbestos plants, or close relatives of employees who work there, have developed lung abnormalities and in some cases cancer. The cycle of contamination may be widening still further. Asbestos fibers have been found in the air and water of many large cities and almost universally in the lungs of their inhabits.
Dr. Selikoff is concerned that even more asbestos will be spewed into the air we breathe as old buildings containing an estimated 25 million pounds of the mineral fibers are torn down or subjected to routine maintenance. Also, he says, another million workers in some 300,000 brake maintenance garages throughout the United States are exposed to daily doses of asbestos. After six years of litigation, Reserve Mining in Minnesota has been forced to stop dumping asbestos-containing tailing from its taconite iron ore mines into Lake Superior, as it has been doing at a 67,000-ton-a-day clip since 1955. Because of the company's contamination of 2000 square miles of Lake Superior with asbestos, Dr. William Nicholson, Dr. Selikoff's colleague at Mount Sinai, estimates that "the fibers ingested by persons in the Duluth area over a period of 15 to 17 years can be as many as workers inhale in their occupational experience."
To counter the rising levels of asbestos in the air both inside and outside asbestos plants, the EPA and other federal agencies have established new standards that limit asbestos concentrations to two fibers per cubic centimeter of air. However. Dr. Selikoff is disturbed that in spite of the large-scale contamination of Lake Superior, similar standards for water are being delayed by a debate now under way as to whether asbestos is as harmful when taken in with water as it is when inhaled into the lungs.
Further, he says that even with the new federal recommendations for "dust counts" and other protective measures, "virtually no inspections are carried out in asbestos working areas by the agencies who should be routinely doing those inspections."
Hit by a number of potentially costly lawsuits which hold that Johns-Manville Corporation, a major producer of asbestos products, failed to protect its employees and warn them about the hazards of asbestos, that company has initiated many stringent procedures which Selikoff says are the best in the business. They include ventilation hoods and air filters for catching asbestos fibers, protective masks and clothing, and other safety measures. The company also labels its asbestos products with warnings to the consumer of the potential hazard involved. Confident that the company can handle the asbestos problem, Johns-Manville has no plans to cut back production. In fact, spurred by an increasing demand for their products, they spent $75 million last year to expand mining and milling facilities in Asbestos, Quebec. But the asbestos time bomb has a long fuse, and the company's problems may not be over. As Roy Steinfurth, head of the Asbestos Workers and Insulators health hazard program, puts it: "We expect to see many more claims, because more people are dying of asbestos disease. We're just now starting to hear of cancer and asbestosis among guys who started working around World War II."
Dr. W. Clark Cooper, the California scientist who headed a National Academy of Science panel on asbestos five years ago, says that a shift to new insulation and fireproofing materials, along with recent government attempts to regulate asbestos emissions in plants, construction sites, and other chancy areas, have considerably improved things for the worker and the population at large in the period since the report was issued. However, he points out, we won't know how seriously the asbestos problem affects the rest of the population until scientists learn more about the effects of the lesser amounts of asbestos inhaled by non-asbestos workers or leached into the water supply from natural asbestos deposits. That will involve performing many autopsies, measuring the amount and location of the asbestos fiber, and then attempting to make some correlation between those levels and the cause of death.
Verdict: The asbestos time bomb is still ticking.
The PCBs, used as coolants in electrical transformers and in other ways, permeate the earth and threaten afflictions ranging from acne to cancer. Toxic fire retardant PBBs were inadvertently mixed with animal feeds and may have contaminated much of the population of the State of Michigan, said Dr. Selikoff. Allied Chemical Corporation faces many multimillion-dollar suits because its insecticide Kepone has poisoned workers and contaminated the James River and other waterways. Recently the FDA saw fit to ban Red Dye No. 2 and Red Dye No. 4 as potential health hazards. Both have already been used widely as coloring agents in many foods, including margarine, maraschino cherries, and jelly beans. Also guilty or suspected of harming health and environment are chloroform, the dry-cleaning agent trichloroethylene, the plastic starting materials styrene and vinyl chloride, and the nitrosamines, compounds found as contaminants in several garden weed killers, and in several meat products.
All of the crises have many things in common. They usually involve chemicals found to be dangerous only after dissemination to the public at million- and even billion-pound levels. The Toxic Substances Control Acts signed last fall by President Ford, may change that situation. Before any substance is sold to consumers, companies will now be forced to show that it does not cause cancer. Each crisis usually reaches a point where environmental and health factors must be balanced against the need for the product in question. Is the elimination of body odor with aerosol sprays more important than keeping the ozone layer intact? Is maintaining bird population as important as feeding the hungry and eliminating malaria in the jungles of Asia and India? Those answers, when complicated by economic losses involved if a product is suddenly banned, do not come easily, but priorities must certainly be established.
Like asbestos, mercury, and DDT, the newly emerging crises are not to be dismissed lightly; but is the threat they pose diluted in the public's mind by a kind of crisis overkill? Possibly, says Dr. Selikoff, observing that when he walks through the halls of Mount Sinai, he is occasionally asked, "Well, what's the carcinogen of the week, doc?" Or is the awareness that so many things in our environments cause cancer just too horrible to contemplate? Maybe, Dr. Selikoff says, but he believes that crisis headlines underscore a hopeful new trend:
"We're in a new phase of research in which for first time we're beginning to identify the causes of cancer. Whereas at one time cancer was though to be an inevitable accompaniment of old age, we realize that each cancer has a cause, environmental or otherwise. Any new cause of cancer may seem like bad news to some people, but it's the kind of a news we have to have in order to get the good news."