Montana Department of Natural Resources, Oil and Gas
"Responsibilities include promoting conservation of oil and gas; preventing waste, contamination, and damage to land and underground strata from oil and gas activities; establishing well spacing units and protecting the correlative rights of mineral owners; and, subject to approval by the U.S. Environmental Protection Agency, regulating all Class II injection wells." 36.1.101f.ii
Department of Environmental Quality
"The Montana Department of Environmental Quality (DEQ) is the agency charged with protecting a clean and healthful environment, as guaranteed by the State Constitution. The DEQ accomplishes this by monitoring environmental conditions and taking proactive measures to preserve and improve the quality of these natural resources."
The PSC is to "supervise and regulate the operations of public utilities, common carriers, railroads, and other regulated industries. "