HEALTH & ENVIRONMENT - OCTOBER 1, 2003

Thirty years later: The lessons of PBBs

If you’re over 30, you lived in Michigan in 1973, and you ate meat or drank milk, you’re among a special class of Americans. You have PBBs in your body. And even more than most Americans, you are part of a gigantic experiment resulting from the post-World War II explosion of chemical manufacture and use in the West.

But if you’re under 30, you should pay attention, too. Because now you’re part of the experiment.

For much of the 1970s, “PBB” (the acronym for polybrominated biphenyls) was a synonym for controversy in Lansing. Some health experts feared a cancer epidemic. Politicians built careers out of investigating PBBs. Some appointed officials lost their jobs because they mishandled the issue. And all of the world sat back to see what would become of PBBs and human health.

Sometime in May or June 1973, the Michigan Chemical Co. accidentally shipped a fire retardant with the brand name of Firemaster to Farm Bureau Services, a supplier for thousands of Michigan farmers, in place of Nutrimaster, a cattle feed containing magnesium oxide. Firemaster was a brand name for PBB, a four-year-old chemical used to reduce the flammability of plastics and electrical circuits. Customers incorporated Firemaster in auto dashboards and casings for telephones and hair dryers. The mistake apparently happened at a time when Michigan Chemical ran out of preprinted bags and hand-lettered the trade names of the two products in black. The similarity of product names or perhaps the smudging of the letters was all it took to make the first link in a disastrous chain of events.In October 1973, the state Department of Agriculture’s head diagnostician inspected the sickened dairy herd of Fred Halbert of Battle Creek and at first suspected lead poisoning. When tests for lead proved negative, the department sought help from Michigan State University and laboratories in Wisconsin, Iowa and New York to isolate the contaminant in the feed. Not until May 1974 did the department determine, with help from Halbert’s son Rick, a chemical engineer, that PBB was the poison. The department then tested feed and farm products across the state. By 1975 the state had quarantined more than 500 farms and condemned for slaughter over 17,000 cattle, 3,415 hogs, 1.5 million chickens, and 4.8 million eggs. PBB was removed from the market. In the 1980s, the state health department confirmed that approximately 95 per cent of Michigan’s population had residues of PBB in fat tissue.

Scientists knew almost nothing about the health effects of PBB, since the chemical had entered commerce so recently. It was clear that some dairy herds were severely harmed. On farms that received the greatest concentration of PBBs in feed, milk production dwindled, there was high calf mortality, and the animals were unstable and listless.

When the feared cancer outbreak in the general population did not appear, the same news media that had sensationalized PBBs as a catastrophe in the 1970s wrote it off. “Michigan’s notorious PBB scare of the 1970s, which predicted alarming spikes in cancer and birth defects by the mid-1990s, turns out to be only that – a scare,” reported The Detroit News in 1997. “…[t]he fears the episode aroused may, in fact, be another example of how allegations of chemical dangers based on incomplete information can escalate into hyped and highly politicized frenzies.”

But some of the long-term research suggests the chemical has harmed Michigan residents. Largely through federal funding from the Centers for Disease Control and Prevention, the state for more than two decades maintained a study group of over 3,500 persons from the most highly exposed farm families in the state. Researchers reported in 1995 that women from the group with higher levels of PBBs in their blood had an increased risk of developing breast cancer. A second study published in 1998 revealed higher risks of digestive cancer and lymphoma among members of the group with higher PBB blood levels. A third study suggested that girls born to women who had the highest levels of the chemical in their blood reached menarche six months earlier than those whose mothers had been less exposed.

Thirty years later, we can say a few things with confidence about PBBs and other chemicals:

— It is better and cheaper to prevent chemical accidents than to study them afterward. Taxpayers spent hundreds of millions in studying, cleaning up, and monitoring the health effects of PBB. Better management of the chemical – clearly-marked bags, for example – would have prevented that.

— We are still not protecting the public from thousands of chemicals. About 99 percent by volume of the chemicals in use have never undergone a full battery of safety tests because they predate the 1976 Toxic Substances Control Act. What many of these may be doing to our bodies and minds is impossible to say.

— Finally, and most disturbingly, so many chemical scares and accidents have occurred since the 1960s that the public’s shock threshold seems to have climbed. Chemicals called PBDEs, used as fire retardants in computers, furniture, and other products, are building up rapidly in fish and wildlife, and last week the Environmental Working Group reported that the level of PBDEs in the breast milk of a young Michigan woman – mother of a newborn – was the third-highest among those tested. PBDEs resemble PCBs, a suspected cancer-causing chemical, in many respects. Public outrage led the state and the U.S. Congress to ban PCBs. Few have even heard of PBDEs today.

But, like PBBs did with older generations, PBDEs inhabit our bodies. And we won’t know for a long time whether that harms us, our babies, or theirs.

Dave Dempsey is the policy adviser for the Michigan Environmental Council, a coalition of environmental organizations. His column appears biweekly.

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