Mercury contamination in and along the Penobscot River

Mallinckrodt (Former Holtrachem Site)

The Mallinckrodt facility, formerly known as the HoltraChem Manufacturing Company, sits on 235 acres on the banks of the Penobscot River in Orrington, Maine. The plant operated under several owners from 1967 through 2000. The facility manufactured chlorine, sodium hydroxide (caustic soda), sodium hypochlorite (chlorine bleach), hydrochloric acid and chloropicrin (a pesticide).

DEP is currently overseeing cleanup activity at the site to ensure that the requirements of the 2010 BEP Order are met. For more up to date and detailed information about the site cleanup and expected timelines, visit Beyond HoltraChem.

• August 25, 2026 - Complaint filed in Penobscot Superior Court
• October 20, 2025 - Notice of Violation (pdf)
• March 19, 2025 - The Mallinckrodt site in Orrington is the subject of a Notice of Violation from the Maine DEP
  Notice of Violation (pdf)

For more information on the history or current status of this site, please contact Chris Swain (207) 485-3852

The Penobscot River

In 2000 the Natural Resources Defense Council (NRDC) and the Maine People’s Alliance (MPA) filed suit against Holtrachem and Mallinckrodt (Mallinckrodt) in Federal district court alleging that under RCRA 42U.S.C. § 6972(a)(1)(B) Mallinckrodt caused an "imminent and substantial endangerment to health and the environment" as a result of discharging mercury into the Penobscot River. A 2002 judicial opinion and order were issued against Mallinckrodt.

Subsequent court orders required the following activities to take place:

• Phase I & II Mercury Study
• Phase III Engineering Study

In 2022, US District Court Judge John Woodcock finalized a consent decree between the NRDC, MPA, and Mallinckrodt outlining the path forward for remediation of the Penobscot River, and authorizing implementation to begin. Information about the settlement, river remediation, progress reports, as well as background including all court orders, the Phase I and II Mercury Studies, and the Phase III Engineering Study are all available at Penobscot River Remediation.

Please note: The State of Maine is not a party to this federal lawsuit, the Phase I-III court ordered studies, or the settlement agreement. This federal lawsuit is separate from the 2025 complaint filed in Maine Superior Court for site remediation at the former Holtrachem site in Orrington (see information above).

For further information please contact Susanne Miller, (207) 557-2700