[JURIST] The US Court of Appeals for the Sixth Circuit [official website] ruled [opinion, PDF] Thursday that the Environmental Protection Agency (EPA) [official website] can suspend power plant construction projects before project completion based on evidence that a plant is underestimating the extent to which the project will affect its aggregate pollutant emissions. The Clean Air Act (CAA) [text, PDF] forbids the construction of new sources of air pollution without a permit, but excepts sources already in operation unless the EPA deems a prospective overhaul as a “major modification” resulting in a “significant emissions increase.” Permits require companies to use the “best available control technology” to mitigate emissions. In 2010, the EPA sued utility company DTE Energy [corporate website] for overhauling its Monroe Unit 2 coal-fired power plant without installing permit-required pollution controls. DTE argued that the permit was not required because its overhaul did not result in a “significant emissions increase.” A judge for the US District Court for the Eastern District of Michigan [official website] ruled in favor of DTE in 2011, holding that any EPA determination as to “major modifications” must occur only “if and when post-construction monitoring shows a need to do so.” The Sixth Circuit overruled the decision Thursday as an unwarranted limitation [WP report] on the EPA’s power to challenge suspected violations of emissions requirements before project completion can provide either supportive or contradictory evidence.

The EPA is often involved in litigation concerning air pollution and CAA compliance. In August the US Court of Appeals for the District of Columbia Circuit ruled [JURIST report] that the EPA overstepped its authority under the CAA by issuing a regulation limiting power plants’ emissions that cross state lines. Also in August the US Court of Appeals for the Fifth Circuit ruled [JURIST report] that the EPA exceeded its legal authority under the CAA by disapproving a Texas plan to issue permits under the Act. In June 2011 the US Supreme Court ruled [JURIST report] that the EPA and the CAA displace claims made under the federal common law of nuisance regarding whether electric utilities contributed to global warming [JURIST news archive]. In January 2011, the state of Texas failed for the third time in two months in its attempt to block EPA regulations [JURIST report] governing greenhouse gas emissions. The U.S. Circuit Court of Appeals for the District of Columbia denied the state’s request to block an EPA program allocating greenhouse gas emission permits under the CAA.