EPA offers the following definition of Operable Unit: During cleanup, a site can be divided into a number of distinct areas depending on the complexity of the problems associated with the site. These areas called operable units may address geographic…

Mine wastes washed down the Clark Fork River from Butte and Anaconda were spread throughout the floodplain, settling in deposits called “slickens.” Slickens can be easily observed throughout the Deer Lodge Valley today; typically, they are dry, sandy areas with…

EPA, working with the Montana Department of Environmental Quality, selected the remedy for the Rocker Timber Framing and Treating Plant in late 1995. The remedy addresses human health risks from potential exposure to contaminated soils and ground water. You can…

The three Warm Springs Ponds cover 2,400 acres at the confluence of Silver Bow, Mill, Willow, and Warm Springs creeks. The ponds were constructed by the Anaconda Company between 1911 and 1959 in an attempt to trap tailings before they…

This Operable Unit encompasses a variety of mine dumps to the immediate west of urban Butte. The area is a popular recreation site for local residents. Recently, EPA began to refer to the site as “Westside Soils.” For most of…

Butte Natural Resource Damage Restoration Council (BNRC) Lower Area One (LAO) is a very active segment of the broader Butte Area One Operable Unit, which has recently received attention after funds from the 2008 Consent Decree between the State of…

Together, the Berkeley Pit and the historic underground mines of Butte, which have been flooded since groundwater pumps were turned off by ARCO in 1982, form the Butte Mine Flooding Operable Unit (BMFOU). EPA and the state of Montana are…

EPA’s latest bulletin, from July 11, 2013, provides an overview of past and ongoing remediation work in the Butte Priority Soils Operable Unit (BPSOU), which includes most of the Butte urban area. Download the bulletin below. In March 2013, EPA…