ROCKFORD, MI -- The Kent County Health Department is embarking on the largest cancer study it has ever undertaken to investigate the health of people potentially exposed to toxic chemicals from Wolverine World Wide tannery waste dump sites.

Brian Hartl, health department epidemiologist, said the state is helping cross-reference incidences of rare cancer around known and suspected properties where Rockford-based Wolverine previously dumped hazardous waste.

Those locations include a known dump at 1855 House Street NE in Belmont, where nearby private drinking water wells are contaminated with per- and polyfluoroalkyl substances called PFAS, (also called perfluorinated chemicals, or PFCs).

Wolverine used the chemicals at its former tannery in Rockford to waterproof leather for Hush Puppies shoe manufacturing. The chemicals were in Scotchgard.

There have been cancers and other illnesses associated with exposure to PFAS compounds on House Street, according to neighborhood residents.

Hartl said phase one will compare occurrences of pediatric and urogenital cancer near tannery waste sites to rates elsewhere in Kent County using the state's cancer registry.

"Once we do that, we'll get a feel for whether we are seeing any difference in cancer rates in targeted areas versus a control group," he said.

After that, the next step is to conduct a survey of residents in affected areas to gather information about illnesses other than cancer associated with PFAS exposure. Hartl is hopeful that survey could begin in a couple months.

Survey methodology is still being determined.

State toxicologists say exposure to PFAS compounds like perfluoroctanoic acid (PFOA) have been linked through human studies to kidney cancer, testicular cancer, ulcerative colitis, pregnancy-induced hypertension, thyroid problems and cholesterol issues. In animal testing, perfluoroctanesulfonic acid (PFOS) exposure is linked to thyroid and liver problems, and reproductive and immune system impacts.

The health department sent clinical guidance to local physicians about PFAS exposure on Sept. 19.

Hartl said study talks with the Michigan Department of Health and Human Services began shortly before a Sept. 12 townhall meeting in Rockford about the House Street dump. The county is hosting a website on the investigation.

County staff began hearing anecdotal reports of cancer and other PFAS-related illnesses this summer during preliminary investigation into well contamination on House Street near property where tannery sludge was dumped in unlined trenches in the 1960s.

Immediately adjacent to the dump site, wells have tested for elevated levels of PFAS. One well on the 1800 block of House Street tested at 37,800 parts-per-trillion (ppt) combined for PFOS and PFOA.

In the 1970s, Wolverine dumped tannery sludge at the Northeast Gravel Co., which has since been redeveloped into the Boulder Creek Golf Club in Plainfield Township.

In addition to the House Street dump and the golf course, Hartl said two properties along 12 Mile Road north of Rockford -- at Northland Drive and Summit Ave. NE, as well as a farm near 14 Mile Road and Northland Drive NE -- are part of the study scope.

Other sites could be added as the study progresses, he said.

"We're still figuring out all the sites that are potentially contaminated sites where dumping occurred," he said. "It's not a static situation."

David O'Donnell, field operations manager for the Michigan Department of Environmental Quality's remediation division, said the DEQ has "heard of eight different locations" in the area where tannery waste is known or suspected to have been dumped.

A couple of those suspected locations have been redeveloped into residential housing, he said.

According to state documents, Wolverine also dumped tannery waste at the State Disposal Landfill along the East Beltline in Plainfield Township, which the DEQ is investigating as a source of PFAS pollution in township utility drinking water.

Wolverine is also testing the Rogue River and the demolished tannery site in downtown Rockford for PFAS compounds this fall.

Richard Rediske, an environmental chemist at Grand Valley State University's Annis Water Resources Institute, said a study is necessary to answer outstanding questions about illnesses suspected to be from local PFAS exposure.

Rediske helped alert the DEQ last year to fact that Wolverine made Hush Puppies with Scotchgard for decades in Rockford.

"The biggest question out there now is the human health impacts," he said. "We need to have a study of symptoms people in the area are experiencing."

The study is the largest of its type the health department has tackled.

"This is the first time we've done something of this magnitude," Hartl said.

"We don't do these types of things typically here at the health department," he said. "We've done small cancer cluster looks in the past, but this is by far the largest geographic area and largest population that has been impacted by an exposure such as this."

In his 15 years at the department, "it's the biggest thing I've done."

The study is being pushed internally, he said. Long-term funding is still a question. Timeframe on a final report is also unknown.

"We know it's going to stretch our capacity," Hartl said. "It's a large undertaking, but it's our duty to address the health concerns of the residents of our county and do what we can to raise their voices."

Hartl said any residents who want to take part in the survey can contact him directly at 616-632-7287 or by email at brian.hartl@kentcountymi.gov.

Wolverine said it "does not have a comment" on the study.