A methodical cleanup effort at the site of the former HoltraChem chlor-alkali manufacturing plant in Orrington, Maine continues to progress towards completion. Mallinckrodt US LLC (Mallinckrodt), the successor to one of the former owners of the site, has assumed responsibility for remediating and restoring the site.
 
Remediation of the former HoltraChem plant site is focused on the 60 acres of the 235-acre site where the manufacturing operations occurred when the plant was in operation. Remediation activities to date have included site investigation, monitoring, demolition activities, excavation of contaminated soil, construction of a groundwater treatment plant, replacements of caps on Landfills 3, 4, and 5, and monitoring the site daily. A team of engineering firms with extensive experience in environmental remediation projects in Maine is working closely with Mallinckrodt US LLC and Maine DEP to complete the project.
 
Site excavation work began in earnest in 2015 and the majority of the remedial areas have now been remediated and restored. During the project, remediation and restoration of the areas known as Landfill Ridge, Landfill 2, Landfills 3, 4, and 5, Southerly Stream, Southern Cove and the Scrap Metal Yard have been completed. The remediation and restoration of the Landfill 1 Area has also been completed. While initial restoration of the Northern Ditch has been completed, a portion of this area was used for staging of Landfill 1 work and final restoration was completed in 2019. Phase 1A, which included excavation and restoration of the former Retort Area and pre-trenching in preparation for installation of a temporary sheet pile wall around the former Cell Building, as well as Cell Building Corrective Measures Implementation work, began on July 26, 2019 and ended in September of 2020. The next phase of work was the Plant Area Corrective Measures Implementation Plan (CMIP) – Concrete and Utility Removal. This was approved by Maine DEP on July 24, 2020. The concrete and utility removal work began in the fall of 2020 and continues into 2022. The Catch Basin #6/Paved Sump CMIP was approved by Maine DEP on August 24, 2022. This work is being conducted concurrently with the concrete and utility work and will continue through the remainder of 2022.