Hoard's Dairyman:
EPA’s PFAS Assessment is Well-Meaning but Wrong
July 17, 2025
By Clay Detlefsen, Senior Vice President, Regulatory & Environmental Affairs
As part of its effort to protect communities from per- and polyfluoroalkyl substances (PFAS), the Environmental Protection Agency has created a draft risk assessment modeling human exposure to the “forever chemicals” PFOA or PFOS from the application of sewage sludge, or biosolids, to farmland. This risk assessment does not model risks for the general public, only very specific populations living on or near sites affected by PFAS from biosolids.
EPA’s goal of the risk assessment is to inform future actions by federal and state agencies as well as steps that wastewater systems, farmers and other stakeholders can take to protect people from PFAS exposure, while also ensuring American industry keeps feeding and fueling the nation. And that’s a worthwhile goal. However, the models used in the draft risk assessment operate on extreme assumptions which don’t account for the reality of agriculture.
One part of EPA’s assessment models the PFAS exposure risk to dairy farmers. In this model, a dairy farm family lives on an 80-acre farm next to a 13-acre lake, where sewage sludge containing one part per billion of PFAS has been applied to the pasture every year for 40 years where the cows are raised. Everyone in the family drinks 32 oz of milk directly from the bulk tank each day, and they also eat eggs and meat from animals on the farm, fish from the nearby lake, and fruits and vegetables grown on the farm. The farm family has lived on the land for the past 10 years.
Sound familiar? Of course not. There’s not a single dairy farm in the country that produces every piece of food a family eats. Furthermore, there are not that many dairies in the United States that pasture raise their cows, and even fewer that apply sewage sludge from municipal wastewater systems to their pastures every year for 40 years. This model also does not account for existing best management practices for the land application of biosolids that farmers often incorporate into their practices.
EPA’s draft risk assessment is yet another example of the agency forcing a square peg in a round hole when it comes to PFAS on dairies. It is important to continue to increase our understanding of PFAS and how it moves through our ecosystem, as well as the potential health effects of PFAS exposure. But EPA’s misguided approach in this model paints an inaccurate picture that does a disservice to everyone.
The National Milk Producers Federation, together with other major agriculture organizations, will be submitting comments to EPA in the coming weeks that explain the shortcomings of the agency’s draft risk assessment on PFOA and PFOS in sewage sludge and why this model should not be used to inform new regulations. There is no clear solution to this issue right now, but NMPF will continue to advise EPA about realistic representation of on-farm practices.
This column originally appeared in Hoard’s Dairyman Intel on July 17, 2025.
