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More than 40 years ago, Michigan’s food supply was contaminated. People’s health is being affected, even now.

All this week, we’re looking at the ripple effects left behind by the company that made that tragic mistake.

In 1973, the Michigan Chemical Corporation shipped a toxic flame retardant chemical to a livestock feed plant instead of a nutritional supplement. The chemical is called polybrominated biphenyl, or PBB. It took about a year to discover the accident.

Here's how Joyce Egginton's book, The Poisoning of Michigan, describes what happened:

In the late spring of 1973 a truck driver known as Shorty made a routine delivery from Michigan Chemical Corporation to Farm Bureau Services, which operated the largest agricultural feed plant in Michigan. Shorty's truck carried about a ton of a crumbly whitish substance which was packed in fifty-pound brown paper sacks and described on the inventory as Nutrimaster, a new trade name for magnesium oxide. An innocuous alkaline, magnesium oxide was a recent discovery of the dairy industry; mixed into feed, it helped a cow's digestion and thereby increased her milk supply...

The trouble was, Michigan Chemical also made a flame retardant chemical, Firemaster, that looked very similar to Nutrimaster.

But while Nutrimaster was harmless, Firemaster was highly toxic. Someone at the chemical company confused the two; Shorty took the wrong bags to the feed plant, and no one there noticed the mistake. PBB was mixed into several large batches of cattle feed which was sold to farmers throughout Michigan. The results were devastating. Tens of thousands of farm animals became deathly ill. Milk production fell. Calves died in their barns. Cows aborted. Lambs were born with gross deformities. Chickens developed strange tremors... and no one could understand why.

Millions of Michiganders consumed contaminated milk, beef, chicken, pork and eggs.

All these years later, researchers are finding that PBB exposure is linked to health problems.

Searching for answers

A team from Emory University held a couple clinics in West Michigan last month. They tested people’s blood for PBB and had them fill out questionnaires.

Daisy Scharmen grew up on a farm in Gregory. Her family’s cows were contaminated. People who worked in the chemical plant and people who lived on farms tend to have higher PBB levels.

“I want to know what our levels are, and how it’s affecting the community and how other people are; their health,” she says.

Toxic effects lingering over decades

Here’s the trouble with the chemical: it sticks around in your body.

Michele Marcus is a professor of epidemiology, environmental health and pediatrics at Emory University Schools of Public Health and Medicine, and she's the lead scientist on the research team.

“We have recently tested about 850 people around the state of Michigan and fully 85% of them still have PBB from this accident 40 years ago in their bodies,” she says.

Marcus says PBB can interfere with the body's hormonal system.

“The most striking findings we have are that people who were exposed during what we call critical periods of development, that is, if they were exposed in the womb because their mother had high levels of PBB or if they were exposed in early childhood, that the development of the endocrine system may be affected,” says Marcus.

She says they’re finding women with high PBB levels have an increased risk of breast cancer. Men who were highly exposed are more likely to have thyroid problems. Daughters of women with high levels of PBB are having their periods a year earlier. As those girls have become adults, they have an increased risk of miscarriages.

Jane-Ann Nyerges was just seven years old when the PBB mix up happened. For at least a year, she ate contaminated beef, chicken and eggs from her family’s farm. Her PBB levels are higher than average, even now, 40 years later.

“I have had ten miscarriages and four ectopic pregnancies over my adult life. Fortunately, I was able to have one child during that time, and she is a complete blessing to me, but my youngest sister is completely barren, never able to even get pregnant,” says Nyerges.

She says Emory’s PBB study helped her understand why she had so many fertility problems.

“It’s like closure for me. To say, okay, it’s not that I was not able to carry a child because there was something wrong with the way I was designed physically, but because of the impacts of the PBB. And that gives me a sense of peace.”

How many generations could be impacted?

The PBB disaster has affected three generations of Michiganders so far.

The researchers say animal studies have found that endocrine disrupting chemicals like PBB can affect four or five generations.

The Emory team has applied for funding to continue the long-term health study. They’re also hoping to get money to open up the study to more people in Michigan who might’ve been affected.

“We’re trying to understand why the PBB does seem to be having such long-lasting effects,” says Michele Marcus. “We do have some preliminary evidence that PBB may affect the expression of genes on the DNA and that can be transmitted down the generations.”

You can find out how to participate in the study here. Michele Marcus says although they don’t currently have funding to test people who are not part of the original PBB registry formed by the state of Michigan in the 1970's, you can complete a Health Research Interest Form and they’ll contact you if they get additional funding.

Do you have a story about how PBB contamination in Michigan affected your life? We'd like to hear your story. You can tell us about it here and hear other people's stories here.

Tomorrow, we continue our series with a look at the pollution left behind by the Velsicol Chemical Corporation. People who live near the old plant are finding dead birds in their yards. We’ll hear why.

*This post has been updated.