Chemical reaction.

• Author: Misch, Ann
• Position: Hazardous effects of chemicals on human health

Researchers are finding evidence that the chemicals we encounter in our everyday routines could be causing subtle but potent health problems other than cancer.

In the giddy, early days of this century's Chemical Age, companies such as Union Carbide and Dow trumpeted the miraculous powers of chemicals ("Better Living Through Chemicals") on billboards and in ad campaigns. And chemicals did bring miracles, from antibiotics, penicillin, and other medical advances to a range of creature comforts our ancestors could never have imagined: synthetic fibers, dry cleaning, spoil-proof food, crop-saving pesticides, contraceptives, contact lenses ... the list is endless. All in all, scientists have heaped more than 70,000 new chemical compounds on the bandwagon of progress, creating every imaginable convenience - and chasing every imagined ache or emptiness from our lives.

But these new creations have generated, along with all their benefits, a long list of problems, including serious health consequences. Our enthusiasm for new chemicals and the products and services they make possible has outstripped our attention to their long-term effects. While billions of dollars have been lavished on product development, marketing, promotion, and advertising, very little has been devoted to observing chemicals' interactions with living things and the environment. And these effects can never be thoroughly tested; the sheer number of combinations these chemicals now represent - in our food, water, clothing, and homes - are astronomical.

The research that has been done on chemicals' health effects has led environmental health experts to one fairly solid conclusion: there is an indisputable link between exposure to some industrial substances and certain serious diseases, particularly cancer. But some scientists are now beginning to look beyond the obvious - cancer and other easily diagnosable problems - to other health consequences of the Chemical Age. What they are finding puts a different face on the miraculous claims that we accepted without question in a more innocent era.

In the summer of 1991, for example, a group of American scientists and other experts met at the Wingspread conference center in Racine, Wisconsin, to talk about what was still just a hunch to each of them: was it possible that the chemicals encountered in people's everyday routines - from weed killer and bug spray to chemical-laced meat and dairy products - could be causing subtle but potent health problems other than cancer?

The scientists at Wingspread had been researching the connection between chemicals and serious health problems in wild animals or laboratory animals - health problems that could affect human beings as well. Few of the scientists knew about the others' research before the conference, and many were startled by the similarities in their findings. "The amount of evidence [for a link] was overwhelming," says Pat Whitten, an anthropologist who attended the conference.

While it is now widely accepted that certain diseases may result from exposure to hazardous substances - leukemia has been linked to benzene, an ingredient in gasoline, for example, and mesothelioma, a form of cancer, is considered a signature of asbestos exposure - the Wingspread scientists have continued to collect evidence that chemicals cause systemic damage by disrupting the functions of the endocrine system, which regulates hormones; the immune system, which defends the body against infectious disease and cancer; and the nervous system. Lowered fertility, abnormal sexual development, eccentric behavior, and lowered resistance to disease were among the health effects the scientists at Wingspread observed in wildlife and laboratory animals. Because most of the damage was so insidious, the scientists determined that similar effects in people might go unnoticed unless researchers specifically hunted for them. At the end of its meeting, the group called for a major epidemiological study to better assess the extent of subtle chemical damage to human health.

Some new advances in toxicology suggest that chemicals need not cause outright disease in order to have dramatic consequences. Other findings shed light on the potency of tiny exposures, and the extreme sensitivity of the developing fetus to chemicals. Since regulation of toxic chemicals has often been aimed strictly at preventing cancer and overt poisoning in adults, many subtle chemical effects on development, hormone regulation, the immune system, the nervous system, and reproduction have never been studied. "Our fascination with cancers has led us to underestimate [chemicals'] other health effects," says Theo Colborn, a World Wildlife Fund zoologist who helped organize the Wingspread conference.

The Chemical Load

Society has understood for centuries the dangers posed by many natural and synthetic substances, often through casual observation of diseases that have beset workers in various "dirty" industries. Lead's dangers, for example, were recognized by the Greeks and Romans. Hippocrates noted cases of lead poisoning among miners in the fourth century B.C. Dioscerides, a Greek physician, reported in the second century B.C., that "lead makes the mind give way." In the late 18th century, Sir Percival Pott, an Englishman, traced a connection between cancer of the scrotum, a hallmark of the profession of chimney sweeping, and the soot in the chimneys the sweeps scrubbed clean. Before their profession was outlawed for humanitarian reasons late in the 19th century, sweeps wedged themselves down soot-lined chimneys and in the process collected particles of cancer-causing coal tar in the creases and crevices of...