Court Rules EPA Cannot Relax Strict Controls on Hazardous Air Emissions During Start-up, Shut-down and Malfunction

In a December 19 decision of potentially broad applicability to fossil fuel-fired electric generators, a divided (2-1) panel of the US Court of Appeals for the DC Circuit ruled that the EPA violated the Clean Air Act when it adopted a final rule that would have lessened controls on emissions of hazardous air pollutants (HAP) when process or associated emission control facilities are in periods of equipment start-up, shut-down and malfunction (SSM).  Specifically, the rejected rule would have supplanted the requirement that HAP emissions be numerically limited by a strict standard based on "continuous" maximum achievable control technology (MACT) with a "general duty" to minimize emission to the greatest extent possible.  Many of the more-than-100 HAPs that are subject to MACT controls under section 112 of the Clear Air Act are by-products of fossil fuel combustion for power generation.

Proposals to relax required MACT controls on HAP emissions during period of SSM began in 1994 when EPA adopted an exemption that would have freed sources from strict numerical MACT standards during SSM periods so long as the source included in its Title V emissions permit an SSM plan that detailed "procedures for operating and maintaining during [SSM] periods and a program of corrective action for" fixing malfunctions.  Later in 2002, EPA ruled that the SSM plan need only exist, but need not be part of the Title V permit, which meant it could be revised by the emissions source without prior approval.  And in 2003 EPA adopted a rule to limit public access to a source's SSM plan.  Public and environmental advocates then protested, resulting in the December 19 decision that the Clean Air Act does not permit EPA to lessen Congressionally mandated "continuous" MACT emission standards for HAPs on a temporal basis during SSM periods.  Notably, the dissenting judge did not disagree with the merits of the majority's decision; rather, he objected that the public and environmental advocates' challenges wer untimely and did not properly present the issue that the majority decided.