An Explanation of Significant Differences (or ESD) is a CERCLA (or Superfund) decision document prepared when there has been a significant change in cost, performance, or cost of a remedy selected in a Record of Decision (ROD). The significant change to the remedy may be as a result of new information.
In 2002, EPA issued an Explanation of Significant Differences for the Butte Mine Flooding Operable Unit (or BMFOU) of the greater Butte area Superfund complex. You can download the full ESD below.
A Consent Decree (CD) is a legal document, approved by a judge, that formalizes an agreement reached between EPA and Potentially Responsible Parties (PRPs) through which PRPs will conduct all or part of a cleanup action at a Superfund site; cease or correct actions or processes that are polluting the environment; or otherwise comply with EPA initiated regulatory enforcement actions to resolve the contamination at the Superfund site involved. The consent decree describes the actions PRPs will take and may be subject to a public comment period.
Together with the Record of Decision and other supplementary documents, the CD governs future management of cleanup sites.
A lawsuit between the State of Montana and PRPs for Superfund sites in Butte and the Clark Fork Basin resulted in numerous CDs for different areas. The Consent Decree for the Butte Mine Flooding Operable Unit, which includes the Berkeley Pit, was published in 2002, and can be downloaded below.
2002 Consent Decree Download