Clark Fork river Cleanup history
WHAT AREA IS BEING CLEANED UP?
The Clark Fork River Superfund Site (referred to as the Clark Fork River "Operable Unit," or "OU") includes the Clark Fork River from its headwaters near Warm Springs Creek in Anaconda/Deer Lodge County to Milltown, just east of Missoula. Within this large area, the 43-mile stretch of the river from Warm Springs downstream to Garrison in Powell County (see map) is known as “Reach A.” This is the reach in which most of the cleanup has, and will continue to, occur (with a small portion in Reach B), and is the focus of the 2023 Clark Fork River Operable Unit Strategic Plan.
WHAT ARE THE POLLUTANTS AND WHERE DID THEY COME FROM?
The primary sources of contamination in the streambanks and historic floodplain are toxic mine tailings mixed with soil. The tailings are laden with heavy metals (primarily Cadmium, Copper, Zinc, Arsenic, and Lead -- known as "the Clark Fork Five") from historic mining, milling, and smelting processes in Butte and Anaconda. Much of this contamination was spread through the floodplain during a historic flood in 1908. More than a century later this contamination continues to threaten human health, plant and animal species, and aquatic and terrestrial habitats. Without intervention, these contaminants would likely remain in place for the indefinite future. (Though not included in Superfund cleanup at this site, Mercury from past mining activities is also found in high concentrations in some parts of the Clark Fork.)
HOW DID SUPERFUND CLEANUP COME ABOUT and WHO PAYS FOR IT?
In 1983 the State of Montana sued the Atlantic Richfield Co. (ARCO - now a subsidiary of British Petroleum and sometimes referred to as BP-AR) under state and federal Superfund laws for damage to natural resources from mine waste contamination. In 2004, a Record of Decision (ROD) was finalized for this site, which describes the cleanup approach mandated by Superfund law. This approach is also known as the "Selected Remedy." In this case, the Remedy authorized the removal of contaminated tailings from "slickens" sites (barren areas with high contamination levels), removal or treatment-in-place of impacted areas, streambank reconstruction, land management planning, and institutional controls.
Final settlements with ARCO were reached in 2008, marked by the signing of the Clark Fork Site Consent Decree and the Clark Fork River Operable Unit (CFROU) Consent Decree. In these settlements the State received about $121 million, which includes ~$94 million for cleanup and ~$27 million for restoration or replacement of injured aquatic and riparian resources.
WHO IS RESPONSIBLE FOR CLEANUP & RESTORATION?
- The Montana Department of Environmental Quality (DEQ) is the lead agency overseeing, managing, coordinating, designing, and implementing the Superfund Remedy, with support and oversight from the US Environmental Protection Agency (EPA).
- The Montana Natural Resource Damage Program (NRDP or NRD) administers the restoration/replacement portion of the settlement and creates the restoration plans and priorities for aquatic and terrestrial resources in the Upper Clark Fork River basin.
- To maximize the use of resources and improve coordination, in October 2023 NRD and DEQ jointly released the Clark Fork River Operable Unit Strategic Plan, which combines latest cleanup and restoration plans. This plan provides general guidance for current reclamation and restoration activities, with more detailed design plans guiding site-specific activities.
WHERE DO THINGS STAND NOW?
Cleanup work in the CFROU began in 2010 on two areas in Deer Lodge and on a stretch of river beginning at Warm Springs Creek (see map). The cleanup plan divides the river into 22 phases from Warm Springs to Garrison. As of spring 2024, cleanup has been completed (or nearly so) on Phases 1, 2, 3, 4A, 5, 6, 15, and 16, and monitoring and maintenance are underway. For more details on current activities, visit our Cleanup Status page. According to the 2023 Strategic Plan, cleanup and restoration activities are expected to continue at least through 2038, with monitoring and maintenance continuing after that time.
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(Cleanup history adapted from DEQ site overview, the DEQ/NRD 2023 Strategic Plan, and other sources.)
LEARN MORE:
* For an overview of the origins of the contamination, Superfund designation, and cleanup efforts to date, see "Superfund: Tailing History" (2019 video)
* Find all related Superfund documents, including Consent Decrees, here.
* Read more about the history of the Clark Fork cleanup and recovery here.
* For an excellent overview of Butte's mining history and Superfund in the Clark Fork basin , listen to the "Richest Hill" podcast (10 episodes), available here.