EPA v. LOWER NEPONSET RIVER

Case summary

On October 15, 2026, EPA entered into an Administrative Settlement Agreement and Order on Consent (ASAOC) with 54 potentially responsible parties to perform the Removal Design of the Non-Time-Critical Removal Action (NTCRA) regarding the Lower Neponset River Superfund Site (the Site ). The Action Memorandum for the NTCRA was issued on November 5, 2025, and addresses the most upstream one-mile reach of the 3.7-mile Site (the Phase 1 Reach ), including sediment and floodplain soils contaminated with polychlorinated biphenyls and other contaminants of potential concern. The NTCRA is estimated to cost approximately $78.6 million. The ASAOC includes an agreement by Respondents to perform the Removal Design (excluding the design of the removal of the Tileston & Hollingsworth Dam, which is the subject of negotiations with another party), payment of EPA?s future response costs associated with the ASAOC, and a commitment to continue negotiations regarding the implementation of the NTCRA.

Defendants (1)

• Various; 54 totalNamed in complaintNamed in settlement

Facilities (1)

• LOWER NEPONSET RIVER

  FROM THE CONFLUENCE OF MOTHER BROOK, BOSTON/MILTON, MA, 02136

  Registry ID: 110071100498

Statutes cited

• CERCLA 122A — Agreement to Perform Work Under 104B

Enforcement conclusions (1)

• LOWER NEPONSET RIVERentered 2026-10-15

  Primary law: CERCLA

Timeline (3 milestones)

• 2026-10-15Complaint Filed/Proposed Order
• 2026-10-15Final Order Issued
• 2026-10-27Enforcement Action Data Entered