The U.S. Environmental Protection Agency said it reached an agreement with Murphy Exploration and Production Co., Pioneer Natural Resources and SGH Enterprises for the monthly monitoring and treatment of the water supply to the residents of Poplar, Montana.
"Murphy, Pioneer and Samson have made a commitment to ensure that the City of Poplar's taps remain safe," said Jim Martin, EPA's regional administrator in Denver. "The companies will continue to monitor water quality and will take all actions necessary to maintain an uninterrupted supply of safe water to residents."
The EPA said wastewater from oilfield production in Montana was found in the water supply for Poplar residents. The wastewater was found to have elevated levels of volatile organic organics, trace metals and inorganic salt concentrations.
The EPA, Montana, aboriginal groups and the U.S. Geological Survey, among others, have known of the groundwater contamination in the region "for several decades."
The companies are to pay $320,000 to cover the costs related to water infrastructure.
The three companies appealed a 2010 decision by the EPA and the agreement is the result of a later mediation process. None of the companies mentioned by the EPA had immediate public statements available.