The simple answer is that the responsible party pays for the cleanup. If the responsible party no longer exists, cannot be determined, or is unable to fund the cleanup, Superfund Trust fund money is used to complete the cleanup. However, the actual work involved in a Superfund cleanup can be very complex and require the efforts of many experts in science, engineering, public health, management, law, community relations and numerous other fields. In the case of the Silver Bow Creek/Butte Area Superfund sites, the Principal Responsible Party is a group of 26 different corporate and government entities.
There are a number of groups within EPA and other government agencies that play a leading role in Superfund site cleanups. EPA has specialists spread out across the ten Superfund regions in the country who are responsible for cleanup activities, including Remedial Project Managers, On-Scene Coordinators, Community Involvement Coordinators, and Site Assessment specialists. National teams of specialists from the EPA, the U.S. Coast Guard, the U.S. Corps of Engineers, and Agency for Toxic Substances and Disease Registry also take part in Superfund efforts.
Once a hazard has been identified and cleanup options have been studied for effectiveness and feasibility, the EPA determines what it believes to be the appropriate cleanup. The party responsible for the contaminants at the site is, in most cases, also responsible for cleanup costs.
In the case of the Butte area, BP-ARCO is the primary responsible party and funds most base-level cleanup efforts, although there are additional responsible parties. Cleanup activities are typically executed by private contractors, coordinated and supervised by the Montana Department of Environmental Quality and/or the EPA. Local governments in the region area also involved in cleanup decisions.