Mercury contamination in and along the Penobscot River

Orrington on the State of Maine map
Map of entire site (pdf)

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).

click to enlarge

DEP is currently overseeing cleanup activity at the site to ensure that the requirements of the 2010 BEP Order are met. It is anticipated that the cleanup activities will be complete some time in 2019. For more up to date and detailed information about the site cleanup and expected timelines, visit

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

Mallinckrodt data in Google Earth

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

More detailed information including all court orders, the Phase I and II Mercury Study, and progress on the Phase III Engineering Study are all available at

On March 19, 2021, the NRDC and MPA lodged a consent decree to settle the case with the Federal District Court. These documents are available for viewing at the NRDC website. The consent decree will need to be approved by US District Court Judge John Woodcock before it is finalized and implementation can begin. Judge Woodcock has indicated that prior to approving and signing this agreement there will be an opportunity for public input. The time and manner of the public input has not yet been determined.

Please note: The State of Maine is not a party to this lawsuit, the Phase I-III court ordered studies, or the settlement agreement. This lawsuit is separate from the 2010 BEP order currently undergoing implementation at the former Holtrachem site in Orrington (see information above).

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