Press Release: 2/13/2026

Lower Neponset Superfund: Phase II Data Summary



February 11, 2026



In early February 2026, the Environmental Protection Agency (EPA) released its Phase II Data Report,* which includes detailed information on samples collected between the Tileston and Hollingsworth (T&H) Dam in Hyde Park and the Baker Dam in Lower Mills, Dorchester.  



Samples were taken from the river bottom, riverbanks, surface water, and fish and mussel tissue to better understand the extent of contamination in this stretch of the Neponset River. 






The report shows that contaminant levels—specifically PCBs—are, on average, much lower in the Phase II section than in the Phase I section (Mother Brook to the T&H Dam). However, the levels still warrant cleanup.




EPA collected tissue samples from fish species commonly found in the Neponset and placed mussels in the River to measure how they would absorb contamination moving downstream.



The Phase II Data Report provides a foundation for understanding contamination in this reach. Additional data collection will take place before EPA releases a comprehensive evaluation of cleanup options for this portion of the Neponset River.



EPA is planning to host a public meeting in March to further explain the data collected and answer questions from the public.





For more information, contact NepRWA Greenways Director Andres Ripley at ripley@neponset.org



Until now, much of the activity on the Superfund site has been focused on the upper stretch located mostly in Hyde Park, but with the release of the Phase II report, the focus is shifting downstream to Mattapan, Milton, and Dorchester.



That makes it more important than ever for members of these neighborhoods to be well represented on the Community Advisory Group (CAG).



If you’re interested in joining the CAG or getting meeting notices, please email NepRWA Greenways Director Andres Ripley at ripley@neponset.org



Fish Advisory



PCBs and heavy metals were found in the tissue of common fish species in the Neponset River, confirming that these contaminants are not only present in the sediment but are actively entering the ecosystem and moving through the food chain.





Eating fish caught in this section of the River may pose a serious health risk.



Before eating any local fish:




  • Check the area for advisories or warnings.

  • Review the Freshwater Fish Consumption Advisory List,published by the MA Department of Health.

  • Contact the MA Department of Public Health, Center for Environmental Health, with any questions: 617-624-5757.



Read more about fish advisories in the Neponset Watershed.



*The Phase II Reach extends from the T&H Dam to the Baker Dam in Lower Mills, spanning approximately 2.7 miles through Hyde Park, Mattapan, Milton, and a small portion of Dorchester.



EPA’s Phase I Reach spans from the confluence with Mother Brook downstream to the Tileston and Hollingsworth (T&H) Dam, covering approximately one mile of river through Hyde Park and parts of Milton.





Lower Neponset Superfund Site overview. Click for larger view.





PCB levels at Rice Islands (in Neponset River). Click for larger view.