In the case of Train, Administrator, Environmental Protection Agency (EPA), et al. v. Colorado Public Interest Research Group, Inc., et al., 1975, the Supreme Court ruled on whether or not the EPA had authority to exempt certain polluters from regulations under the Federal Water Pollution Control Act Amendments of 1972. The act required that all point sources of pollution obtain a permit before discharging pollutants into navigable waters and set standards for these permits. However, it also allowed for exemptions if compliance with these standards would result in unreasonable economic hardship. The Colorado Public Interest Research Group challenged an exemption granted by the EPA to a mining company arguing that such exemptions were beyond EPA's statutory authority and contrary to congressional intent. The Supreme Court held that Congress intended for there to be no exceptions made regarding discharge limitations other than those explicitly provided in statute itself; therefore ruling against any implied power within EPA’s mandate allowing them discretion over granting exemptions based on economic considerations alone.

In the dissenting opinion for Train v. Colorado Public Interest Research Group, it was argued that the majority's interpretation of Section 21(b)(4) of the Federal Water Pollution Control Act Amendments was incorrect. The dissenters believed that this section should be interpreted to allow citizens to bring a lawsuit against any person alleged to be in violation of an effluent standard or limitation under this chapter, not just against the Administrator of Environmental Protection Agency (EPA). They contended that Congress intended for citizen suits to play a significant role in enforcing pollution standards and limitations. By limiting these suits only against EPA administrators, they felt it would undermine congressional intent and weaken environmental protections by reducing accountability for polluters.