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During its early period of operations in the late 1960s and early 1970s, the former HoltraChem chemical plant in Orrington released mercury-contaminated wastewater into the Penobscot River Estuary. The facility was operated at the time by Mallinckrodt US LLC’s corporate predecessor and was later acquired and operated by other companies, including HoltraChem Manufacturing Company.


In 2000, Maine People’s Alliance and the Natural Resources Defense Council filed suit against Mallinckrodt US LLC under the Resource Conservation and Recovery Act, asking the U.S. District Court for the District of Maine to order an independent study to evaluate the harm caused by mercury contamination and then order appropriate remedial measures to clean up the Estuary.

In 2002, Mallinckrodt US LLC was found liable, and the Court concluded that the mercury may endanger health and the environment. That decision was upheld on appeal in 2006.

The Court appointed a Penobscot River Mercury Study Panel to investigate the condition of the Estuary and the need for remediation. Over the course of nine years, the Study Panel produced Phase I and Phase II studies. The study results were the subject of a trial in 2014 and a Court decision in 2015. The Phase I and Phase II studies are available here.


The Court ordered a Phase III engineering study to identify cost-effective remedial actions that would accelerate the recovery of the Estuary. The study and its recommendations were filed with the Court in 2018. The Phase III engineering study is available here.


The parties agreed to a settlement that was generally modeled on the Phase III study’s recommendations. The settlement is set forth in a Consent Decree that was submitted to the Court for approval in March 2021. The Court held a Fairness Hearing in October 2021 to seek public input about whether the proposed Consent Decree was fair and in the public interest. In October 2022, the Court approved the Consent Decree and its overall plan for cleanup of mercury pollution in the Estuary.


Greenfield Environmental Trust Group, Inc. (Greenfield), was appointed as the independent Trustee to manage the two trusts created to clean up and restore the River.


Greenfield has served as the court-approved trustee of various environmental trusts responsible for cleanup of contaminated sites nationwide. Greenfield’s work has been recognized with international, national, regional and state awards from governmental agencies and professional associations.


Separate from the remediation work intended to accelerate the recovery of the Estuary is the cleanup process underway for the former HoltraChem plant site that is directed and overseen by the Maine Department of Environmental Protection (DEP). Information about that cleanup is available at Beyond HoltraChem and on Maine DEP’s website.

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