The U.S. Environmental Protection Agency (EPA) began a preliminary assessment and site inspection (PA/SI) in 2009 and listed Newtown Creek on the National Priorities List (NPL) of Superfund sites in 2010.

In 2011, EPA issued an administrative order on consent (AOC) that requires the potentially responsible parties (PRPs) to complete a remedial investigation and feasibility study (RI/FS) for Newtown Creek under EPA oversight. Today, the Newtown Creek Site is in the Remedial Investigation/Feasibility Study (RI/FS) phase. The remedial investigation (RI) serves as the mechanism for collecting data to characterize site conditions, determine the nature of the waste, assess risk to human health and the environment, and conduct treatability testing to evaluate the potential performance and cost of the treatment technologies that are being considered. The feasibility study (FS) is the mechanism for the development, screening, and detailed evaluation of alternative remedial actions.

The RI and FS are conducted concurrently – data collected in the RI influence the development of remedial alternatives in the FS, which in turn affect the data needs and scope of treatability studies and additional field investigations. This phased approach encourages the continual scoping of the site characterization effort, which minimizes the collection of unnecessary data and maximizes data quality.

In terms of administration, the site has been divided into Operable Units (OUs). Operable units (OUs), may address geographic areas, specific problems, or medium (e.g., groundwater, soil) where a specific action is required. The remedies are displayed for the OU numbers indicated in the original decision document. OU numbers may change over time. OU1 is the entire Creek from the mouth of the East River to the head of the Creek. OU2 is the Superfund aspect of the City of New York’s approach to combined sewage overflows (CSOs). There was a proposed OU3 which would have covered an early action remedy for the first two (2) miles of the Creek, however this option was not proceeded with. 

As of March 2023, EPA has issued notice of liability letters naming the following entities as Potentially Responsible Parties (PRPs): The City of New York, BP America, Inc., The Brooklyn Union Gas Company (d/b/a National Grid), ExxonMobil Oil Corporation, Phelps Dodge Refining Corporation (now Part of Freeport McMoRan, Inc.), Texaco, Inc. (now part of Chevron Corporation), the Consolidated Edison Company of New York, National Railroad Passenger Corporation (AMTRAK), American Premier Underwriters, Inc., Connell Limited Partnership, The Long Island Railroad Company, Motiva Enterprises, LLC, Shell Oil Company, Simsmetal East LLC (a subsidiary of Sims Metal Management, Inc.), Darling Ingredients Inc, Sunoco Entities (Sunoco Inc, Energy Transfer L.P.), Harsco Corporation, The Brinks Company, and ConocoPhillips. EPA continues to identify PRPs.

After the OU1 RI/FS is completed, EPA will select a remedy (i.e. a cleanup plan) in a decision document called a Record of Decision (ROD). Leading up to the ROD, EPA selects a preferred remedy and presents this remedy in a document called the Proposed Plan. After the ROD, detailed cleanup plans will be developed and put in place during the remedial design and remedial action (RD/RA) stage. Cleanup completion and monitoring follow, during the construction completion and post-construction completion stages. Once the site remedies are fully protective of public health and the environment, EPA will remove the site from the NPL (a process known as “delisting”).