Forty years ago, Michigan had one of worst mass poisonings in U.S. history

A veterinarian for more than six decades, Alpha Clark was instrumental in helping to uncover Michigan’s PBB contamination crisis in the 1970s. “I knew and my clients knew that there was something wrong, but we didn't get no help,” Clark says. (Photo by J. Carl Ganter/

Alpha Clark was there when they started to bury the carcasses. The tomb – a trench, actually – was in a field in remote southeastern Kalkaska County, a place of quiet amid the pine forests of Michigan’s Lower Peninsula.

“Boy, they buried a ton of them up there,” Clark recalled during an August visit at his home. “I used to know the numbers but I don't remember the total number. They took cattle. They took sheep. They took hogs. They took chickens. They took milk. They took eggs. Everything is buried in there.”

Clark is a veterinarian who lives in McBain near Cadillac, where he has doctored sick animals for six decades. In the late 1970s, he was at the front lines of a chemical contamination crisis that engulfed the state and was one of the worst mass poisonings in U.S. history.

Polybrominated biphenyl, or PBB, was a fire retardant manufactured by Michigan Chemical Corporation, in St. Louis, Michigan. An error at the factory in the spring of 1973 changed the state’s health history. Workers mistakenly placed bags of PBB, a highly toxic chemical, in a shipment of livestock nutritional supplements. The supplements were destined for a Farm Bureau center where they – and the PBB – were mixed with cattle feed and distributed to farmers across the state.

Cows that ate the contaminated feed started acting strangely. Farmers near McBain called on Clark for assistance.

“We knew something was wrong,” Clark said about the cows he treated. “The farmers and I knew something was wrong, and that's the truth. We didn't know what was wrong. We knew that the animals weren't like they used to.”

Tens of thousands of animals were stricken ill. Cows developed digestive problems. They stopped eating and milk production dropped. Calves died. The chemical worked its way into the fat of the mothers and then into the milk, which was shipped to supermarkets.

Soon, PBB was found in the breast milk of Michigan women. Researchers today are testing whether the harm from PBB exposure can be inherited, passed from mother – or father – to child. Early results indicate that is the case.

At the height of the crisis, the state quarantined herds and then, finding no quicker or better option, ordered contaminated livestock to be exterminated. Starting in 1974, the carcasses -- more than 32,000 cattle, pigs, sheep, and poultry -- were brought to the Kalkaska pit and buried.

The Michigan Chemical plant in St. Louis that produced PBB did not last much longer. Closed in 1978, the site was placed on the federal Superfund list five years later because of contamination in the Pine River, which abuts the property, and in groundwater. Cleanup is still ongoing.

The Department of Environmental Quality began monitoring groundwater around the Kalkaska burial site in 1977. The site had been selected because it was three miles from the nearest river and a natural underground clay layer above the water table would impede any contamination that escaped the lined pit.

The department stopped monitoring in 2015 because of “minimal likelihood of movement” of PBB off the site, according to Nick Swiger of the DEQ. One monitoring well in the shallow aquifer registered a low-level PBB detection in 1984, but nothing before or since.

“We stopped monitoring because it’s been so long and nothing has been found,” Swiger said.

About this project

Bridge Magazine teamed with Detroit Public Television and Circle of Blue, a Traverse City-based nonprofit, for this special report on the multiple threats to Michigan’s groundwater. Brett Walton is a contributor with Circle of Blue. The reporting partners will host a live broadcast to discuss the report and similar threats worldwide at 1 p.m. Oct. 1. To register, follow this link.

Like what you’re reading in Bridge? Please consider a donation to support our work!

We are a nonprofit Michigan news site focused on issues that impact all citizens. In an era of click bait and biased news, we focus on taking the time to learn both sides of a story before we post it. Bridge stories are always free, but our work costs money. If our journalism helps you understand and love Michigan more, please consider supporting our work. It takes just a moment to donate here.

Pay with VISA Pay with MasterCard Pay with American Express Donate now

Comment Form

Add new comment

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.


Wed, 09/26/2018 - 9:01am

Milk cows only BUT meat prices went up... It was just another scam pulled on the middle class to raise prices!!!

Wed, 09/26/2018 - 11:05am

Are you saying this never happened?

Cindy Eby
Thu, 09/27/2018 - 8:53am

Not just milk cows, but all animals that had been fed the contaminated feed, which included cattle, pigs, sheep and chickens. I remember. We lived just 7 miles from the chemical plant. They dumped a lot of crap in the landfill, which is now fenced off, as is a large swath of land near there. There was a peach orchard that we bought from every year that was permanently evacuated. A golf course shut down.
We were eating our own meat that we raised, our own milk, butter, etc. I have always wondered if my body carries the same load as others in Michigan.

Charles Buck
Wed, 09/26/2018 - 9:44am

I can understand reducing the frequency of monitoring tests, but stopping monitoring removes all margin of safety. The so called "comeback state" now refers to Michigan's past chemical indiscretions returning to haunt our children's drinking water.

Wed, 10/10/2018 - 12:51pm

Agreed completely.

Wed, 09/26/2018 - 3:53pm

I specifically remember the delay in notifying the public about the problem. By that time I was supposedly doing the best I could for my new baby by breastfeeding. I found out I had been poisoning him instead.

Wed, 10/10/2018 - 12:54pm

When people come before profits, we will no longer have these kind of disasters. This mom feels for you. I can't imagine the heartache caused in the moment of your own relations.

Wed, 09/26/2018 - 5:22pm

I live in Kalkaska County and would like to know 'exactly where' this 25 acre parcel is. Can anyone help me find out where this plot is....or point me in the direction to find out??

Sun, 09/30/2018 - 2:33pm

Camp Grayling, I believe.

Newman's Local ...
Wed, 10/10/2018 - 12:50pm

44.5704920, -84.8938490
These are the coordinates.
It's on the corner of 8 Point Rd and Pine Rd.
Follow my page on FB by searching, Newman's Local PBB Report.
It is completely unacceptable that monitoring has ceased.

Wed, 09/26/2018 - 5:25pm

I live in Kalkaska County and would like to know 'exactly where' this 25 acre plot of land is located!! Can anyone direct me to the appropriate path to find out?

Wed, 10/10/2018 - 12:55pm

44.5704920, -84.8938490
These are the coordinates.
It's on the corner of 8 Point Rd and Pine Rd.
Follow my page on FB by searching, Newman's Local PBB Report.

John Fisher
Wed, 09/26/2018 - 6:16pm

This Michigan Chemical/Velsicol Corp. PBB disaster resulted in a DNR criminal investigation. Yes, CRIMINAL. The result was a multimillion dollar settlement to the State of Michigan. Accident mixing of bags, come on! Dig a little further for the truth.

Sat, 11/17/2018 - 9:46am

Michigan the Bhopal of the Midwest

Ilene Cook
Thu, 09/12/2019 - 6:45pm

What can be done to make them continue testing?? I live near this!!