On December 19, 2008, as a result of a court case (Sierra Club v. EPA), the U.S. Court of Appeals for the District of Columbia (DC Circuit) vacated the "Startup, shutdown, and malfunction (SSM) exemption" of the National Emissions Standards for Hazardous Air Pollutants (NESHAPs) Subpart A (40 CFR 63.6 (f)(1) and (h)(1)). The ruling concluded that even during periods of SSM, an affected source must comply with applicable emissions standards associated with the relevant source category. On July 22, 2009, EPA clarified that this vacatur only affected facilities subject to NESHAPs which incorporate sections (f)(1) and (h)(1) by reference. NESHAP subparts which have direct regulatory text which exempt or excuse SSM events are unaffected by this vacatur.
Since the court ruling, there have been numerous stays on the determination and currently, the "SSM exemption" is still in effect. If the SSM exemption vacatur is made final, the affect on industry will be significant as sources will be required to demonstrate ongoing compliance with emissions standards, even during SSM events.
Since EPA adopted the SSM exemption in 1994, subject facilities were required to develop and implement an SSM plan that would indicate how the facility would do its best to maintain compliance with the standards, even during SSM. The SSM was required to be incorporated into the facility's Title V permit, by reference, making it available for public review. In 2002, EPA changed the Title V requirement such that the SSM plan must only be noted as being in place at the facility. In 2006, EPA went further, determining that a facility need not implement their SSM plan during an SSM event since they were already under a "general duty" requirement to minimize emissions during these scenarios.
The court, however determined that the SSM exemption should be vacated because it violates the Clean Air Act Section 112 requirement that NESHAPs must apply continuously.
If a facility determines that the DC Circuit ruling will affect site operations (i.e., applicable NESHAPs for the facility do not include specific provisions regarding SSM events), the facility should begin planning immediately on how it will comply with the presumably more stringent emissions standards contained in the source category NESHAP during SSM events. Additional controls may be required, especially during current economic conditions that may be resulting in more startup and shutdown scenarios. Industry groups will undoubtedly respond with new questions about the validity of each emission standard since emissions during SSM events were not considered when the standards were initially set.