Sewage sludge may not sound like anything useful, but farmers in Indiana, and across the U.S., use it as a cost-effective form of fertilizer on their fields.
The sludge, typically collected and dried at wastewater treatment plants, is known as biosolids when used for agricultural purposes, and is regulated in Indiana under a set of permits meant to protect public health and the natural environment.
Indiana places safeguards on where the sludge can be applied and what crops are suitable for its use, as well as limits on the concentrations of certain pollutants contained in the product.
One notable omission of safeguards, however, are what environmental advocates call “forever chemicals” or per- and polyfluoroalkyl substances, often called PFAS for short.
The synthetic chemicals got their nickname due to the strong bond formed by some of the molecules that make them up. These carbon-fluorine bonds resist degradation, meaning PFAS stay in the environment for decades or longer.
There are more than 21,000 chemicals classified as PFAS, and the compounds are so widely used in consumer products and other materials that they have been detected in the surface snow in the arctic and the placenta of pregnant humans.
Six of those compounds currently are regulated under the U.S. Environmental Protection Agency’s drinking water program, but the agency in July reopened a comment period for the public to submit their opinions on regulating certain PFAS within biosolids.
“One of EPA’s top priorities is to Make America Health Again, and reducing risk from PFOA and PFOS in biosolids is a critical part of that effort,” Jess Kramer, assistant administrator for the agency, said in a written statement.
The rule was first proposed under former President Joe Biden’s administration in early 2025, but was delayed until EPA revisited the draft rule this year. The comment period has been extended to allow “additional time to thoroughly review” the regulations, according to federal documents.
Indiana currently has no guidelines for these chemicals found in sludge despite lawmakers trying to get some on the books.
“There are not any reporting requirements for PFAS content in biosolids and IDEM does not have a regulatory mechanism to require tracking of these compounds,” Indiana Department of Environmental Management spokesperson Allen Carter wrote in an email to IndyStar.
A spokesperson at Indiana Farm Bureau said the organization did not have anyone available for comment.
Biosolid use in Indiana
Since January 2025, about 202,000 dry tons of biosolids have been directly applied to land in Indiana totaling around 28,000 acres.
In an effort to protect Indiana’s agricultural lands and human health, state Rep. Maureen Bauer, D-South Bend, introduced legislation in 2025 that would have put limits on the amount of PFAS contained within biosolids applied to agricultural fields.
The regulation would have limited PFAS within biosolids to no more than 100 parts per billion.
Bauer, who farms a few acres of grapes and sat on the agriculture and rural development committee at the Statehouse, told IndyStar she is always trying to bridge the gap between agriculture and environmental stewardship.
Farmers face many challenges, Bauer said, whether it’s the volatile cost of diesel or exposure to herbicides and pesticides. When it comes to PFAS in biosolids, Bauer said other states have turned to outright banning the practice of applying sludge to farm fields.
“We’re such an agricultural state that a ban is probably not the route we would take but just regulate it and label it, Bauer said. “I always believe Informing the public is the best practice.”
Tracking, not banning PFAS in Indiana
This idea resonates with environmental advocates at the Hoosier Environmental Council too.
“We’re not going to deal with PFAS by regulating various entry points,” HEC’s executive director Sam Carpenter said. “We need to deal with the source of it.”
Limiting the amount of these chemicals in biosolids can also come with a whole host of new issues, Desi Rybolt with Indiana Conservation Voters said. If PFAS are removed from the sludge, it still needs to end up somewhere, and that could be in a landfill or even an incinerator. Both options still could lead to risks to human health and the environment.
“The best answer is to just limit the use of chemicals at the source,” Rybolt said.
A statewide ban is unlikely, Rybolt said, but making sure the state monitors and addresses problems from PFAS contamination before they happen are better routes to keeping Hoosiers safe.
Studying PFAS and biosolids in Indiana
PFAS is a complicated societal issue, said Linda Lee, a Purdue University professor who has studied PFAS since 2005. But when the chemicals are controlled at the source, the benefits are obvious.
Two specific compounds, PFOS and PFOA, were phased out of use in the U.S. in 2002 and 2015, respectively, and a direct connection can be seen between that and reduced levels of the chemicals in blood samples, Lee said.
Lee conducted a study in rural Tippecanoe County testing for about 50 different types of PFAS in more than 100 wells to find out if any of the water there would exceed drinking standards for PFAS.
“Actually, everything was quite low,” Lee said.
This led her to consider the way agricultural lands are drained in the state. This is typically done with an underground drainage system known as tiling. This system removes water from the soils and directs it to a different area — typically surface waters like streams or ponds.
Lee found a greater frequency of PFAS in the rivers, streams and tributaries, which could come from a variety of different sources other than just the use of biosolids. PFAS in these surface waters could be from local wastewater treatment plants or different industries that use PFAS in their day-to-day operations.
The use of biosolids on agricultural fields needs a tempered approach, said Ty Hoskins, another PFAS researcher at Purdue.
“Land application of biosolids is a major way PFAS are moving from wastewater treatment plants to the agricultural landscape. There’s no denying that,” Hoskins said. “But then there are all of these other benefits of this practice that need to be balanced.”
There are companies that make a living by applying these biosolids to farmlands, while others help farmers comply with regulations and doing so in a safe way.
“They’re not bad guys in this story,” Hoskins said. “They’re trying to help the farmers they’re trying to make a living, and they’re trying to make sure that these environmental regulations are complied with, but with the addition of the PFAS issue, they’re kind of stuck in the middle.”
Indiana is not the only state grappling with the issue of PFAS, and each state is approaching it differently, said Gretchen Salter, policy director at the national advocacy group Safer States.
“PFAS is certainly the thing that has woken states up to sludge,” Salter said. “And there are a number of things a state can do. The first and foremost is testing.”
States and environmental regulators do not know the extent of a problem they cannot see, Salter said, but setting up a testing regimen is not easy.
Some farmers may not want to participate in a state program that tests their soils for PFAS due to the costs it could incur on the farmer. Instead, Salter said, the sludge could be tested before it ever hits the land.
Maine, for example, set up a remediation fund for farmers to tap into and Salter said that has been an effective strategy for tackling the PFAS issue within biosolids.
“We don’t want farmers to bear the burden,” Salter said.
Karl Schneider is an IndyStar environment reporter. You can reach him at karl.schneider@indystar.com. Follow him on BlueSky or Twitter @karlstartswithk
IndyStar’s environmental reporting project is made possible through the generous support of the nonprofit Nina Mason Pulliam Charitable Trust.
This article originally appeared on Indianapolis Star: ‘Forever chemicals’ are on Indiana’s farmlands. Here’s how they got there
Reporting by Karl Schneider, Indianapolis Star / Indianapolis Star
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By Karl Schneider, Indianapolis Star | USA TODAY Network
