Superfund

View the April 2026 Lower Neponset Superfund Site Public Meeting Presentation here.

Get answers to FAQs from the April Public Meeting here. (In English, Spanish, Haitian-Creole)

The US Environmental Protection Agency has designated the Lower Neponset River as a Superfund Site

NepRWA is committing extensive staff and financial resources to ensure the cleanup of the Lower Neponset River Superfund Site is done right and lives up to its transformative potential.

Upcoming Public Meetings

Latest Superfund News

Additional Information

See our FAQs below for more information about PCBs and recreation along the River.

What is the EPA Superfund Program?

The Superfund Program protects human health and the environment by investigating and cleaning up often abandoned hazardous waste sites and engaging communities throughout the process. Many of these sites are complex and need long-term cleanup actions. Those responsible for contamination are held liable for cleanup costs. EPA strives to return previously contaminated land and groundwater to productive use.

Is it safe to eat FRESHWATER fish caught in the Lower Neponset River?

No. People should not eat fish caught in the freshwater portion of the Lower Neponset River. This includes the area from the Baker Dam in Milton / Dorchester Lower Mills upstream to the Hollingsworth and Vose Dam in Walpole. While the concern over PCB-contaminated sediments only extends upstream to Hyde Park, fish that have spent time in the Lower Neponset can easily swim as far upstream as the dam in Walpole.

Is it safe to go fishing in the Neponset River? What about eating fish from the SALTWATER portion of the River?

You may enjoy recreational, catch and release fishing in all areas of the Neponset River, so long as you don’t eat FRESHWATER fish caught on the Neponset Mainstem as described above. Touching freshwater fish is not a concern. Saltwater fish caught downstream of the Baker Dam in the portion of the Neponset River known as the Neponset River Estuary are not exposed to the higher levels of PCB sediments found further upstream and spend much of their lives in areas other than the Neponset River. Follow general guidelines for all saltwater fish when deciding whether to eat saltwater species caught in the Neponset Estuary. There are no special precautions for consumption of saltwater species caught in the Neponset.

Are there PCBs in the water along the Neponset River?

PCBs do not readily dissolve in water. As a result downstream of Mother Brook there are PCBs in the water, but they are at extremely low levels that are not a concern for human contact. However, you should not drink water taken directly from the Neponset River because of concerns about other pollutants.

May I walk and bike along the Lower Neponset River?

Yes, you may safely walk, bike, and engage in other land-based activities along the Neponset . PCBs are typically found in the “mucky,” organic mud at the bottom of the river. There should be no human health concerns with land-based recreation along the River, except for eating freshwater fish as discussed above.

May I canoe, kayak and boat along the Neponset?

Yes, you may canoe, kayak and boat along the Lower Neponset. PCBs on the Lower Neponset are primarily concentrated in the deep layers of mucky “organic” mud accumulated behind the two dams on the Lower Neponset and a former dam. While boaters might come in contact with mud in the River to a limited degree, this should not be a health concern for several reasons.

First, PCBs in the River are bound to organic matter in the mud and the primary hazard would be eating mud rather than touching mud. Second, areas of the River that have sandy or rocky bottoms without accumulations of mucky organic mud will have minimal if any PCBs because there is little or no organic matter with which the PCBs can bind. Lastly, even in areas of the River that have organic mud deposits near formal canoe launches, the PCB concentrations in surface sediments are generally low. Higher PCB concentrations are found behind the dams several feet or more below the surface of the mud. While the risk of PCB exposure to boaters via mud is limited, we do recommend washing hands and shoes after recreation if you get muddy, as much because of other pollutants as because of PCBs.

Can I swim in the Lower Neponset River?

While our goal is to get all of the Neponset and its tributaries to be safe for swimming all the time, the Lower Neponset River does not yet meet this goal consistently. This is primarily because of remaining problems with sewage pollution and untreated rain runoff from surrounding streets and neighborhoods, though potential exposure to PCBs in mud deposits would also be a concern with swimming in the area between Mother Brook and the Baker Dam. That said, the Lower Neponset often does meet bacterial pollution standards for swimming and almost always meets bacterial standards for boating.

Is there a project website, email list, or some other mechanism to keep track of the project and receive timely notice of meetings or document releases?

An official Superfund epa.gov website has been created, where overall information will be posted throughout the project.

View the April 2026 EPA Public Meeting Presentation PDF

Lower Neponset River Superfund Site Phase 1 EE/CA Virtual Public Hearing, July 9, 2025
Lower Neponset River Superfund Site EE/CA Informational Video, June 2025
Lower Neponset River Superfund Site Public Meeting, Nov. 12, 2024

Read: EPA Lower Neponset Presentation, Oct. 5, 2021

View responses to the Q&A from the meeting.

For any questions, reach out to Zanetta Purnell at Purnell.zanetta@epa.gov

Tristan Pluta
U.S. EPA Remedial Project Manager
617-918-1258
pluta.alexander@epa.gov

General Information
CALL TOLL-FREE CUSTOMER SERVICE 1-888-EPA-7341

NepRWA’s Role

NepRWA is dedicating staff time and financial resources to ensure the cleanup is done right.

We’re performing technical and regulatory reviews to ensure the cleanup protects public health, improves
recreation, and supports healthy fish and wildlife, including passage for herring and shad.

We’re also working to ensure the Community Advisory Group provides a strong voice for local residents, and that state and local agencies do their part.

Get Involved!

The Lower Neponset River Superfund Community Advisory Group (CAG) is made up of community members and stakeholders from the Lower Neponset Superfund Site.

The group provides valuable input to the EPA throughout the Superfund cleanup process.

The CAG meets on the third Tuesday of each month at various locations and aims to ensure representation from all four communities near the Site (Hyde Park, Mattapan, Dorchester, and Milton). We welcome more members to represent these areas.

Get more information about the CAG here.

Questions? Please email NepRWA Community Engagement Strategist Karen Groce-Horan.

Project Site

The EPA defines the Lower Neponset River Superfund Site as a 3.7-mile stretch of the Neponset River from the confluence with Mother Brook in Hyde Park, just upstream of Dana Avenue. It extends downstream to the Walter Baker Dam, located upstream of Adams Street in Dorchester and Milton.

Cleanup Phases

Phase I of the cleanup includes the first mile of the Site between Mother Brook and the T&H Dam in Hyde Park and Milton.

This is the most contaminated stretch, and it will be cleaned up through an accelerated process at an estimated cost of $80 million.

Both riverbanks and the entire river bottom will be extensively excavated and reconstructed. The crumbling T&H Dam will be removed.

In early 2026, the final design process for Phase I will begin, lasting about 12 months, after which 3-4 years of construction is expected.

Community input and independent technical review are critical throughout the planning, final design, and construction process to ensure that pollutants are properly removed.

It’s also critical that the bed and banks of the cleaned River be designed to serve as habitat for fish and wildlife, and as a vibrant recreational resource for the entire community.

Phase II is the 2.7 miles from the T&H Dam to Lower Mills. It includes Hyde Park, Mattapan, Dorchester, and Milton. It is much less contaminated.

Studies of this area are underway, and many key decisions remain, such as what the future of the Baker Dam will be and how much material will be removed from the River.

The goal is to have studies and design work for Phase II completed so that the Phase II construction can begin as soon as Phase I is finished.

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

Freshwater fish from the Lower Neponset roam as far upstream as Walpole and, via tributaries, to many communities, making fish unsafe to eat and impacting stream health miles away.

What is “Superfund?”

Superfund is the federal program that helps clean up major pollution sites across the US. It is run by the U.S. Environmental Protection Agency (EPA), and it tackles the most challenging sites.

What’s the Problem?
The Lower Neponset was home to many industrial facilities that discharged to Mother Brook or the Neponset. Learn more about the Neponset’s Industrial past.

Studies to restore herring and shad runs blocked by state-owned dams discovered river-bottom sediments contaminated with polychlorinated biphenyls (PCBs) and other industrial chemicals. After years of advocacy, the Lower Neponset became a Superfund site in 2022.

Not a “Local” Issue
Freshwater fish from the Lower Neponset roam as far upstream as Walpole and, via tributaries, to many communities, making fish unsafe to eat and impacting stream health miles away.

The Superfund cleanup will also clear the way for restoring herring and shad runs to most of the Watershed, helping to revive the entire Neponset River ecosystem.

Background

On March 14, 2022,  the Lower Neponset River, between Mother Brook in Hyde Park and the Baker Dam in Milton/Dorchester Lower Mills, was designated as a Superfund site by the EPA.

This designation ensures critical federal resources will be available to clean up PCB-contaminated sediments at the bottom of this section of the Neponset River.

The process is expected to involve an extensive study of the contamination and the potential parties responsible for it, as well as opportunities for public input, the possible implementation of initial cleanup actions in certain areas, and the eventual implementation of comprehensive cleanup efforts.

NepRWA has advocated for the cleanup of this section of the River for over 20 years, and we are excited to see this work getting underway.

Because the contamination is primarily in the mucky organic mud at the bottom of the River, many recreational activities along the Lower Neponset and the Neponset Greenway can continue as usual while the cleanup progresses.

Tileston and Hollingsworth (T&H) Dam, Hyde Park