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Project Clean Up

After nearly 15 years of site review, engineering studies and substantial site cleanup work at the former HoltraChem manufacturing plant in Orrington, the final environmental remediation process has begun and is being led by Mallinckrodt US LLC (Mallinckrodt) and a team of several engineering firms with significant experience in and personal ties to Maine.


The successful project is embodied in the following goals:

  • Complete restoration of the land, allowing for reuse and development in the future;

  • Finish the project with zero injuries or health effects;

  • Apply a safe, innovative, state-of-the-art approach to complete the project;

  • Prevent release of site contaminants to the environment due to remedial activities;

  • Work cooperatively with the regulatory authorities; and

  • Be a positive contributor to the community.

After a highly competitive process that brought eight qualified engineering firms to Orrington to review the site, Mallinckrodt selected a combined team of CDM Smith, Geosyntec Consultants, Inc. and Anchor QEA LLC, which was assembled with a focus on firms and individuals who have specific professional experience working in Maine and on projects similar to the cleanup of the former HoltraChem chlor-alkali plant. In coordination with Woodard and Curran, a Portland firm, and Sevee & Maher Engineers, Inc., a firm located in Cumberland, which are already handling groundwater remediation tasks at the site, this team of professionals will lead the remediation project to its completion.​

Global Environmental Engineering Firm CDM Smith Takes the Lead in Orrington

  • The challenge for Mallinckrodt was finding a team that had experience in remediating a chlor-alkali manufacturing site, working with mercury contaminated soils and sediments, designing the remedial plans and specifications and managing the associated logistics while doing it all in a manner that protects human health and the environment.  After extensive interviews, Mallinckrodt selected a team comprised of three firms under the leadership of CDM Smith, a Cambridge, MA based international engineering firm.

  • In addition to its substantial remediation experience around the world, CDM Smith and John Weston, the Remediation Project Manager, have direct experience at the Orrington site. Under Weston’s direction, CDM Smith managed the dismantling of the former cell building and the subsequent demolition of numerous buildings and infrastructure at the site.

  • CDM Smith is responsible for overall project management and coordinating the work of Geosyntec and Anchor QEA. With this team in place, plus the two firms already involved in the Site (Woodard & Curran and Sevee & Maher Engineers), this objective was achieved.   

Sevee & Maher's Expertise and Decades of Experience is a Perfect Match for Orrington Site's Remediation


  • Sevee & Maher Engineers, Inc. located in Cumberland, Maine was started in 1985 and includes environmental and civil engineers, geologists, data experts and groundwater modelers.

  • Sevee & Maher Engineers' expertise in hydrogeology, geotechnical engineering, and landfill design and construction fits well with other engineering firms working as part of the remediation team at the Orrington Site.

  • The complex geological setting at the Orrington Site presents engineering challenges related to the chemicals present and their potential mobility in groundwater, and SME is well qualified to address the hydrogeological aspects of the remedial designs.  

  • In the meantime, the groundwater extraction system designed and installed by SME is working very effectively to control contamination from leaving the site. 

Geosyntec Consultants Brings Maine Experience and an International Reputation to Former HoltraChem Site

  • Geosyntec was founded more than 30 years ago as environmental regulations began to be developed.

  • The firm has been working in Maine since 1988 and opened an office here in 2002. Geosyntec has now completed more than 30 projects in the State, including extensive work at the Crossroads Landfill in Norridgewock.  


  • Geosyntec has also served as expert consultants to the Maine Department of Environmental Protection (DEP) and they literally wrote the book (a manual) on the design and construction of final landfill covers for the DEP.


  • Geosyntec has also provided consulting services related to the decommissioning and remediation of several former chlor-alkali facilities similar to the former HoltraChem facility throughout the northeast and south, and has partnered with other consultants on the remediation of a former chlor-alkali plant in British Columbia.

Health and Safety is a Priority

While all environmental remediation projects require a healthy and safety plan before proceeding, each site has its own unique challenges and that plan needs to be designed for that particular site. The HoltraChem remediation involves the excavation and removal of two site landfills and removal of contaminated site soils where the plant once operated. It will also include the recapping of the three remaining landfills to permanently encase them, long after the remediation is completed and the engineers have left the site.

Designed to protect the health and safety of site workers and the community around them, the Health and Safety Plan (HASP) is an exhaustive compendium of site health and safety concerns based on a clearly articulated set of goals:

  • No one is to be injured while on the job or exposed to unacceptable health risk;

  • Protect the air, soil, water and nearby sediment from any increase in contamination;

  • No violations of state or federal environmental or worker safety laws or regulations.

The HASP for the Orrington site includes a four-page Table of Contents, including a listing of figures, tables and attachments. The topics range from the specific responsibilities of the project manager and the Safety and Health Officer to preventing contamination and steps for decontaminating equipment – large and small – that will be used to excavate site soils for transportation.

“The objective in building out a health and safety plan is to anticipate anything that could possibly go wrong and then build protocols and procedures to make sure that nothing goes wrong,” says Mallinckrodt’s Director for Environmental Remediation Kathryn Zeigler. “They are highly trained professionals when they arrive on site, but they continue to train their employees and managers to adapt to the specific conditions of the project. We have a great deal of confidence in our team and in the plan that they have developed.”

Site engineers will have the benefit of constant air and groundwater monitoring that will detect any increase in mercury contamination while the excavation and removal process is ongoing. And they also have the advantage of CDM Smith’s 15-year track record working at the Orrington site where they have acquired detailed knowledge of the site’s hydrogeology, terrain and soil from their work preparing the site for its final remediation and restoration.

Experience is an advantage, but experience at the very site where the work will take place is a great advantage.

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