Learn where dioxin lurks, and buy products that don't contribute to dioxin poisoning.

Some think that dioxin contamination of Michigan waterways has motivated a study downplaying its toxicity.

RODALE NEWS, EMMAUS, PA—Best known as the highly toxic contaminant in Agent Orange, the defoliant used by the U.S. military during the Vietnam War, dioxins are among the most hazardous—and most studied—environmental pollutants Americans have to cope with today, linked to everything from cancer to birth defects to skin rashes. But a study just published by chemists working for Dow Chemical, a company with a long legacy of dioxin contamination in Michigan, indicates that the chemicals don't cause as many cancers as previously believed.

THE DETAILS: Dioxins are created anytime chlorine is manufactured or used, whether that's bleaching paper at the mill to make it bright white, using chlorine to disinfect and sanitize drinking water, or in the case of Agent Orange, using chlorine-based chemicals to manufacture other, more potent chemicals. Dioxins build up in animal fat and in fish and are extremely persistent, finding their way into air and water where they're capable of traveling thousands of miles. The dioxin used to manufacture Agent Orange and other types of pesticides, 2,3,7,8-tetrachlorodibenzodioxin (TCDD), is considered a known human carcinogen by the World Health Organization, but is only "reasonably anticipated to cause cancer" by the U.S. Department of Health and Human Services. Other forms of the chemical have been linked to birth defects, skin diseases, changes in glucose metabolism, and interference with certain hormones.

Published in the August issue of the American Journal of Epidemiology, the study by Dow scientists looked at the cancer-causing affects of TCDD in workers at a Dow Chemical plant in Midland, MI, where a chemical used in pesticides like Agent Orange was made from 1942 to 1979. The scientists tracked incidences of all cancers, diabetes, ischemic heart disease, and respiratory diseases in 1,615 of the plant’s workers who had been exposed to TCDD at least one day a week. They collected 61 years' worth of data and found that cancer and cancer-related deaths were slightly elevated only for one type of cancer, soft-tissue sarcoma; other studies on dioxin have found elevated levels of numerous cancers, including leukemia, non-Hodgkin's lymphoma, and lung cancers, but, says lead author Jim Collins, PhD, director of epidemiology at Dow Chemical's Midland plant, rates of cancers in those studies haven't been consistent.