Tracking the hazy air quality at “hotspots” in southern Wisconsin and beyond

A national reporting project outlines little-known airborne polluters across the state and their associated risks.

A national reporting project outlines little-known airborne polluters across the state and their associated risks.

Header image: Illustration: An ethylene oxide molecule is shown superimposed over a map of Rock County, Wisconsin. Map via Library of Congress.

Wisconsinites have become accustomed to all sorts of contaminants seeping into their everyday lives. 


From toxic “forever chemicals” in Madison‘s (and La Crosse‘s, and Wausau‘s, and Peshtigo‘s) drinking water, to manure-tainted kitchen faucet water in Kewaunee County, to lead water pipes and paint that hinder youth development in Milwaukee, pollutants in Wisconsin travel all sorts of paths and contribute to a variety of serious health problems.

Industrial pollutants also correlate with increased cancer risk in several parts of Wisconsin. An interactive map the nonprofit newsroom ProPublica released in November tracks airborne, industrial chemicals across the country, identifying several “hotspots” in our state. 

ProPublica‘s map is part of an extensive look at how communities across the country are exposed to dangerous, cancer-linked, airborne chemicals on a daily basis. The interactive map outlines Wisconsin facilities that produce industrial pollutants at rates higher than the recommended U.S. Environmental Protection Agency (EPA) standards.

ProPublica monitored EPA reports from 2014 to 2018 and found “more than 1,000 toxic hot spots across the country” and “an estimated 250,000 people living in them may be exposed to levels of excess cancer risk that the EPA deems unacceptable.” 

The report goes on to explain how the EPA defines these risks: “The EPA’s threshold for an acceptable level of cancer risk is 1 in 10,000, meaning that of 10,000 people living in an area, there would likely be one additional case of cancer over a lifetime of exposure.” 

The report outlines dozens of facilities located in Wisconsin, but only three meet the qualifying standards to be considered a “hotspot”: Evonik Industries in Janesville, Evonik Materials Corp. in Milton, and Oshkosh Defense Corp. in Oshkosh. Just beyond Wisconsin’s northern border, emissions from L.E. Jones Co. in Menominee, Michigan waft over into Dairy State territory. 

A hotspot, in this context, is any location that can be identified as emitting pollutants that contribute to lifetime cancer risks from industrial sources in excess of the EPA’s acceptable risk. 

A screenshot from ProPublica’s map of industrial pollution hotspots in the United States shows the location of Evonik Materials Corp. in Milton, Wisconsin

While the EPA sets acceptable risk standards for chemical pollutants, any increase in human consumption of lead, chemical vapors, and other by-products of (and ingredients used in) industrial facilities is not safe.

Living in or near a hotspot does not immediately mean residents are going to get cancer. Airborne toxins are linked to numerous cancers, but cancers also develop based on a person’s tobacco use, exposure to chemicals like pesticides, as well as diet and genetics. This report outlines how these Wisconsin facilities contribute to increased risk—sometimes at 10 times the recommended standards—in combination with other health factors. 

Wisconsin’s Cancer Alley connection

The two hotspots ProPublica identified in Rock County both belong to a multinational chemical conglomerate with a history of toxic emissions.


Evonik Industries is a German chemical production company with 33 production facilities in the United States. Evonik—whose original parent company, Degussa, has been in operation since 1843 and has a troubled history that includes refining Nazi gold during World War II—operates two facilities in Wisconsin within a few miles of each other: Evonik Industries in Janvesille and Evonik Materials Corp. in Milton. 

ProPublica reported that the area around Evonik Materials Corp. in Milton has an estimated excess lifetime cancer risk 5.7 times higher than the EPA’s acceptable risk. Evonik in Janesville has an estimated excess lifetime cancer risk 2.5 times higher than what the EPA deems acceptable.

Data analysis by Tone Madison found that of the 33 production facilities the massive chemical company operates in the United States, the Rock County facilities are among those associated with the highest elevated cancer risks, according to the EPA’s measurements. 

The Evonik production facility with the highest emissions was a Reserve, Louisiana material production facility. This facility has a risk 19 times higher than the EPA recommendations and is located in the deadly Cancer Alley, an 85-mile region in Louisiana with both the highest concentration of petroleum production facilities in the country and an abnormally high risk of cancer, especially in predominantly Black communities, compared to the national average. 

A screenshot from ProPublica’s map of industrial pollution hotspots across the United States shows a swath of Louisiana along the Mississippi River known as “Cancer Alley.”

Evonik Materials Corp. in Milton ranks second among the company’s U.S. operations in terms of the cancer risks ProPublica found. The company’s Goose Creek, South Carolina silica production facility, with a three times increased risk rate, comes in third. The Janesville facility is fourth.

The Milton and Janesville plants have a long history. The Janesville facility got its start in 1957 as Varney Chemical Company, which produced water-softening materials. Varney sold the company to Goldschmidt Chemical Corp. in 1999. Two years later, the German chemical company Degussa bought the Janesville facility. In 2007, Degussa changed its name to Evonik Industries. The Janesville plant currently produces ingredients for fabric softeners, paper additives, car sprays, hair conditioners, and skincare products. It employs roughly 85 people.

The Milton plant has been in operation since 1967 and has a more colorful history. Tomah Products founded the facility, and in 2006 sold it to Air Products & Chemicals, an international chemical production company, for approximately $115 million in cash. In 2017, Evonik acquired a division of Air Products & Chemicals’ specialty chemical additive companies, including the Milton facility, for $3.8 billion.

Tomah Products was founded by Milton native Mike Clumpner in 1967. In 1979, Steve B. King, a former FBI agent (who, in June 1972, held Martha Mitchell, wife of then-United States Attorney General John N. Mitchell, against her will in a hotel room to prevent her from breaking the news about the Watergate scandal, an account she has brought forth and King has danced around), joined Tomah as a part-owner and general manager. King, a failed Senate candidate with deep ties to the Wisconsin Republican Party, became CEO and owner of Tomah Products in 1994 after a management-led buyout.

King served as the finance chair of the Janesville Republican Paul Ryan’s congressional campaign, and he was also instrumental in nominating Ryan (who coincidently stuffed envelopes for King during King’s failed 1988 Senate run) to run for Vice President in 2012 on the Republican ticket.

King is the founder of the private equity firm King Capital, where Paul Ryan’s older brother Tobin previously worked. King, who is not Czech and doesn’t speak the language but is a big fan of the country’s chemical production history, was appointed and confirmed as a US Ambassador to the Czech Republic by former President Donald Trump in 2017. He served in the role until 2021.

When King was still CEO, Tomah Products had a hand in Louisiana’s Cancer Alley. In 1999, the Milton-based company purchased the aforementioned Reserve, Louisiana facility and later sold it, alongside the Milton facility, to Air Products in 2006. Ownership of both Milton and Louisiana plants would eventually wind up in Evonik’s hands. 

Evonik in Milton currently produces chemicals that are used in its Personal Care and Household Careline. The two Rock County plants are among a group of five sites in the country that produce this line of chemicals, including facilities at Mapleton, Illinois, Reserve, Louisiana, and Hopewell, Virginia.

Limiting emissions

According to ProPublica, both of Evonik’s Rock County facilities emit ethylene oxide, among other carcinogens such as acrylonitrile, benzyl chloride, chloromethane, and cobalt.

The EPA describes ethylene oxide (EtO) as a colorless, flammable gas that humans are mainly exposed to through breathing. The EPA states that while short-term exposure to the chemical is not likely to cause health risks, it can cause headaches, dizziness, nausea, fatigue, and shortness of breath. Long-term exposure can be linked to cancers. The EPA states that “the greatest cancer risk is for people who have lived near a facility releasing EtO into the air for their entire lifetime.”

The EPA states that children are more susceptible to harm from EtO, as the chemical is mutagenic and can harm children’s still-developing DNA. The Milton plant is a quarter-mile away from Milton West Elementary School and the adjoining baseball diamonds of La Mar Park. 

Jeff LaBrozzi, site manager of Evonik’s Janesville and Milton plants, said in a statement that the company welcomes oversight from state and federal regulators, and is committed to reducing EtO emissions through technological enhancements, independent, periodic monitoring, and improved leak detection.

LaBrozzi says both the Milton and Reserve, Louisiana plants use EtO to make materials for several familiar consumer products, including laundry detergents, silicone products, and foam additives. He says EtO (again, a colorless gas linked to various forms of cancers) is an important ingredient in making “consumer-friendly products that are non-toxic, biodegradable, and economical.”

“At both Milton and Reserve, we have increased our leak detection and repair (LDAR) efforts,” LaBrozzi says. “This has resulted in a 75% decline in fugitive emissions at Milton. In Reserve, LA, we reduced ‘fugitive emissions’ by 92% between 2014 and 2020. The ethylene oxide emissions from the stack of our Louisiana plant have been reduced by 21.6% between 2014 and 2020.”

EPA and DNR reporting verifies Evonik’s claims of its decline in fugitive emissions of EtO.

A fugitive emission is an unintentional release of a chemical vapor inside of an industrial facility. The culprit can be anything from a pressurized valve leak to a broken chemical storage container.

Rock County Public Health Department Director Katrina Harwood told Tone Madison that the DNR informs the Bureau of Environmental and Occupational Health, a division of the state’s Public Health Department, which then informs the county’s public health department about local emissions. Harwood said the county’s public health department is not directly involved in monitoring or investigation and directed questions to the Wisconsin Department of Natural Resources (DNR).

DNR spokesperson Craig Czarnecki says the department has worked with Evonik for several years to obtain the best annual emission estimates for EtO emissions, but the calculations have proved challenging. He says the majority of calculated emissions come from over 2,000 intermittently released sources distributed throughout a facility—such as valves, flanges, connectors, pumps, and seals—as opposed to stacks or vents.

The Wisconsin DNR has enforced air pollution regulations in the state since 1988 under the state’s Control of Hazardous Pollutants administrative rule.

Evonik is in the process of building a new, taller emission stack it hopes to complete by the end of this year, and installing an enhanced Leak Detection and Repair (LDAR) program that will increase monitoring and quicken response times to leaks. The company submitted an application to the DNR at the beginning of February and it is currently pending review. 

DNR documents show that Evonik is also in the process of implementing voluntary measures at the Milton facility “in order to reduce the overall cancer risk in nearby residential areas.”

An overhead image of Evonik’s plant in Milton, outlined in purple, from the company’s recent DNR application to increase its air quality monitoring. According to DNR documents, areas outlined in yellow are areas with frequent human and animal activities.

An EPA report says that the DNR mailed notices to 12 nearby households in September 2021 to inform them about the plant’s EtO admissions and efforts to reduce them. In an email, Milton Mayor Anissa Welch told Tone Madison that neither her office nor City Council members have received communications from residents about the plant since the letters were sent. 

Welch said Evonik has worked closely with the city, the DNR, and the EPA to reduce emissions and keep the neighboring community informed. 

“I am not aware of any information that indicates that Evonik is no longer cooperating with the DNR and EPA,” Welch says. “We have not been notified that there has been any change in plan or change in how the EPA, DNR, and Evonik are working together in addressing the implementation of these standards.”

Hotspots further north

As the independent media outlet Oshkosh Examiner reported in a January 2022 story based on ProPublica‘s data, Oshkosh Corporation’s Oshkosh Defense plant has an estimated excess lifetime cancer risk 5.8 times higher than the EPA’s acceptable risk. 

Oshkosh Corp. has over a century of roots in the Oshkosh community, and manufactures an array of heavy-duty vehicles, from fire trucks to cement mixers. But it’s best known for the military vehicles of its Oshkosh Defense division, which has been rolling out trucks and all-terrain vehicles since World War II.

The plant emits cobalt and chromium compounds, according to ProPublica’s review of EPA data. A wrinkle in regulations makes it difficult for the public to understand which form of chromium a given facility emits, and this has a problematic implication for tracking the health effects. One form, hexavalent chromium, is a known carcinogen, whereas another, trivalent chromium, is not. ProPublica explains that EPA reporting of chromium usage doesn’t allow facilities to distinguish between the two.

ProPublica‘s data analysis shows the defense contractor had a spike in emissions in 2017. 

The Oshkosh Examiner‘s reporting found that “of the 5,064 pounds of chromium compounds released by the plant in 2017, most were disposed of off-site. An even larger amount, 74,000 pounds, was recycled. But 12 pounds were released through stacks, and 621 pounds were classified as fugitive emissions.”

Since 2017, the defense plant has had a downward trend in emissions.

Just past the northern tip of Wisconsin, LE Jones Co. of Menominee, Michigan manufactures valve seats and other items for engine companies. The company has an estimated excess lifetime cancer risk 9.9 times higher than the EPA’s acceptable risk. The Menominee company’s emission area crosses the Wisconsin border into Marinette, a city that is no stranger to the risks of industrial products and chemicals.

LE Jones has been in operation since 1941 and currently employs over 400 people in the area. According to ProPublica, the Michigan company emits cobalt, chromium, and nickel. 

Michigan nonprofit newsroom Michigan Advance released a December 2021 report based on ProPublica‘s findings of Michigan’s potential toxic hotspots in which LE Jones CEO David Doll “lambasted” the reporting project. In a statement, Doll told the Michigan Advance “It is disappointing and concerning that ProPublica would engage in this misleading effort to spread needless alarm in our community.”

Closer to home

The ProPublica map also outlines sites where “additional cancer risk is greater than 1 in 100,000—10 times lower than the EPA’s threshold, but still high enough to be of concern, experts say.”

In Dane County, there are three sites that meet those criteria.

BouMatic, a milking system production company on Stoughton Road in Madison, registers a 1 in 24,000 risk. A Stoughton Trailers plant on Veterans Road in Stoughton registers a 1 in 30,000 risk.

Sun Prairie thermal coating company Thermal Spray Technologies’ two facilities register an average of 1 in 68,000 risk. EPA records show that these facilities emit chromium compounds and nickel.

Protecting Wisconsin air

The EPA sets the ground floor for air quality standards in the country, and states can create more stringent regulations if they choose. The EPA identified 29 facilities in the country that contributed to cancer risks equal to or greater than one-in-10,000 in a 2014 National Air Toxics Assessment (NATA) assessment. Milton’s Evonik chemical plant is one of the identified sites.

Before 2016, the EPA referred to EtO as a possible carcinogen, but in 2016 the agency reassessed cancer risks associated with the colorless gas and recognized the long-term cancer risks associated with exposure. In May 2021, the Office of the Inspector General (OIG) issued a report outlining various ways for the EPA to overhaul its approach to addressing EtO and associated elevated lifetime cancer risks.

The 2021 OIG report also outlines how the EPA has not developed standards for chemical plants and their affected areas and lacks proper processes to review and assess emissions when pollutant risks increase. It states that without new standards, the EPA will not be able to fulfill a 1994 executive order in which then-President Bill Clinton directed federal agencies to address environmental problems that disproportionately impact minority and low-income populations. The 2021 report notes that “minority and low-income populations are disproportionately impacted by chloroprene and ethylene oxide emissions.”

According to Census data, both the Milton and Janesville chemical plants do not have a high concentration of minority and low-income populations surrounding them. The two chemical plants are in largely rural, semi-industrial regions of their respective cities. 

An aerial photo of Evonik’s Janesville plant, which produces ingredients for fabric softeners, paper additives, car sprays, hair conditioners, and skincare products. It employs roughly 85 people. Both Evonik plants in Wisconsin are monitored by the EPA and DNR, as well as environmental groups such as Clean Wisconsin. Photo via Evonik Industries.

For the facilities that fall outside of the purview of EPA monitoring, the Wisconsin DNR regulates chemical production facilities and other sites prone to emissions.

Chelsea Chandler, the Climate, Energy, and Air Program Director for Clean Wisconsin, said Wisconsin’s environmental regulators typically cover more than what’s federally required in both its tracking and compliance.

Since the Clean Air Act (CAA) was implemented in the 1970s, Chandler says, Wisconsin’s air quality has improved. 

“Our overall air quality is greatly improved since we started paying attention and tracking and regulating these pollutants and air toxics,” says Chandler, “but we need to make sure that we are doing correct oversight.”

In 2018, Clean Wisconsin sued the EPA when the federal agency attempted to roll back air quality reporting standards related to smog at the same time the EPA said areas of Kenosha, Door, Manitowoc, Sheboygan, northern Milwaukee, and Ozaukee counties needed to reduce their smog levels.

In 2018, Republican state legislators introduced joint bills in the assembly and senate to limit the DNR’s reporting on anything not required by federal standards. A 2018 Clean Wisconsin map showed that dozens of Wisconsin facilities wouldn’t be regulated by the DNR and would have been left to the EPA as the sole monitoring agency if these measures had been signed into law. Both 2018 bills failed in the Senate and the Assembly.

More recently, Clean Wisconsin joined a legal brief filed to the United States Supreme Court by numerous national environmental groups to advocate for the prevention of CAA rollbacks. 

Chandler says understanding air quality concerns, like EtO and others outlined on the ProPublica map, is just one piece of the puzzle when understanding the state’s ongoing pollutant risks. She said Wisconsinites should be aware of compounding hazards, from wildfire smoke to lead paint, take steps to minimize their cumulative risk overall, and remain civically engaged to shift the individual burden.

“It shouldn’t all be on the individual, these regulations exist for a reason,” Chandler says. “So you shouldn’t have to be worried about the air that you’re breathing or the water that you’re drinking or whether paint in your houses is harming your health.”

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