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The National Emission Standards for Hazardous Air Pollutants (NESHAP), codified in 40 Code of Federal Regulations (CFR) Part 63, set emission standards and monitoring, recordkeeping, and reporting requirements for specific source categories that emit HAPs.  NESHAP Subpart A, the General Provisions, includes general requirements for NESHAP subject facilities, including provisions for startup, shutdown, or malfunction (SSM) events.  Subpart A previously stipulated that facilities minimize emissions during SSM events but did not require that the emission source achieve emission levels (during SSM events) that are required by the relevant NESHAP Subpart during normal operation.1   This allowance during SSM events is also referred to as the “SSM exemption.”  On October 16, 2009, the United States Court of Appeals for the District of Columbia Circuit (DC Circuit) issued the mandate vacating the SSM exemption from Subpart A of the NESHAPs.

On December 19, 2008 in Sierra Club versus (v.) the Environmental Protection Agency (EPA), the DC Circuit vacated the SSM exemption of Subpart A, concluding that even during periods of SSM, an affected source must comply with the applicable emission standard required by the relevant source category subpart.  Since this finding, there have been numerous stays on the determination but the SSM vacatur was ultimately mandated on October 16, 2009. The effects on industry will be significant, as each subject source will be required to demonstrate compliance with applicable emission standards even during SSM events. 

Note that the SSM exemption vacatur only affects source categories subject to the SSM requirements by virtue of incorporating Subpart A by reference.  If a particular NESHAP explicitly exempts applicable sources from meeting emission limits during SSM events, then the SSM exemption in that subpart will continue to apply regardless of the Subpart A vacatur.  As the Subpart A vacatur was mandated, industry should also expect challenges to any SSM exemptions specific to an individual NESHAP.  EPA intends to evaluate each of the source category-specific SSM provisions in light of the court’s decisions.2

Milestones Related to the SSM Exemption Vacatur
  • September 12, 2008 –Sierra Club v. the EPA was argued before the DC Circuit8.
  • December 19, 2008 the DC Circuit vacated the SSM exemption.
  •  January 28, 2009 – the DC Circuit granted EPA a 60-day extension to file for rehearing of Sierra Club v. EPA and the SSM exemption vacatur was stayed during this 60-day period.
  • April 3, 2009 – the American Chemistry Council requested a rehearing of Sierra Club v. EPA and the SSM exemption vacatur was stayed until the DC Circuit decides if the case will be reheard.
  •  May 29, 2009 – EPA issued a brief that opposed industry requests for the DC Circuit to reconsider its decision in the Sierra Club v. the EPA case.
  • July 22, 2009 – Mr. Adam M. Kushner, Director of Civil Enforcement for EPA, issued a guidance letter titled “Re:   Vacatur of SSM Exemption (40 CFR 63.6(f)(1)  and 63.6(h)(1)”.
  • July 30, 2009 – the DC Circuit denied the American Chemistry Council request for a rehearing.
  • August 5, 2009 – EPA filed a motion seeking a 60-day stay on the mandate to vacate the SSM exemption.
  •  August 6, 2009 – industry interveners filed a motion to stay the mandate pending appeal of the decision to the United States Supreme Court.
  • September 23, 2009 the DC Circuit granted EPAs request and denied the industry intervenors motion. 
  • October 16, 2009 the DC Circuit issued the mandate vacating the SSM exemption.

    8Case No. 02-1135.
History of the SSM Exemption

In 1994, EPA adopted the SSM exemption and required that subject facilities develop and implement an SSM plan.  Note that this is a current requirement in Subpart A per 40 CFR 63.6(e)(3).  The purpose of the SSM plan is to require a source to “demonstrate how it will do its reasonable best to maintain compliance with the standards, even during SSM.”3   EPA also required that the facility’s Title V permit incorporate the SSM plan by reference.  The reason for inclusion of the SSM plan into the Title V permit was so that EPA, the state agency, and the general public would be able to review  and comment on the plan.  It is important to note that the Sierra Club did not challenge the SSM exemption at this juncture.

In 2002, the EPA removed the requirement that the SSM plan be included by reference in a facility’s Title V permit but instead required that the Title V permit include a condition that the SSM plan must be in place at the respective facility.4   In 2003, the EPA updated the procedure for public review such that a concerned party could request a copy of the SSM plan from the state agency, who would then request a copy of the SSM plan from the specific source.5   The Sierra Club challenged the SSM exemption legitimacy during the 2002 and 2003 rule updates.

In 2006, EPA further determined that a facility was not required to implement its SSM plan during an SSM event because facilities are already required to minimize emissions during these scenarios under the “general duty” clause.  Additionally, EPA removed the requirement that the public be provided a copy of the SSM plan upon request to the delegating agency; instead, if the delegating agency has a copy of the relevant SSM plan, the agency is required to provide the public with a copy of the plan.6   In the 2006 revisions, the Coalition for a Safe Environment challenged the EPA regarding the 2006 rule changes.

Summary of Court Findings

In its December 2008 ruling, the DC Circuit determined that the SSM exemption should be vacated by reasoning that the SSM exemption violates the Clean Air Act (CAA) Section 112 requirement that the NESHAP must apply continuously.  Under the CAA Section 112(d)(2), EPA must set “emission standards that require the maximum degree of reduction in emissions ….”  CAA Section 302(k) defines an emission standard as “a requirement established by the State or the EPA which limits the quantity, rate, or concentration of emissions of air pollutants on a continuous basis ….”  The DC Circuit therefore concluded that the emission standard required during normal operation in conjunction with the general duty to minimize emissions during an SSM event does not constitute continuous application of an emission standard.7  
EPA argued that the Sierra Club was required to petition the SSM exemption when the rule was initially incorporated into Subpart A with the 1994 rulings, since the CAA requires that “petition for review … shall be filed within 60 days from the date notice … appears in the Federal Register.”  EPA also interprets 40 CFR 63.6(e)(1)(i) to be the relevant standard during SSM events, and that the specific emission standard listed in each subpart applies during normal operation, unless otherwise specified in the relevant subpart. 

On October 16, 2009, the vacatur of the SSM exemption was mandated by the DC Circuit and the SSM exemption is no longer in effect for subject sources.

How Does the SSM Exemption Vacatur Affect Your Facility?

Facilities subject to a NESHAP Subpart should determine whether or not their operations are covered by the SSM provisions of Subpart A or SSM provisions from a specific NESHAP.  As an example, gas turbines subject to NESHAP Subpart YYYY are not immediately affected by the SSM exemption vacatur because Subpart YYYY, 63 CFR 6105(a) includes the following language, “You must be in compliance with
the emission limitations and operating limitations which apply to you at all times except during SSM.”  However, combustion sources at pulp mills are impacted by the vacatur because NESHAP Subpart MM does not include specific provisions regarding SSM events and the provisions of Subpart A are incorporated by reference.  Table 1, which is not comprehensive, shows a sampling of NESHAP Subparts and the effect the SSM exemption vacatur has on the particular source category.

If you determine that the Subpart A SSM exemption does not apply to your facility, then the current DC Circuit ruling has no immediate effect on site operations.  However, as discussed earlier, the likelihood exists that individual NESHAP regulations that allow an SSM exemption may be challenged or revised by EPA in the future.

If you determine that the mandate will affect site operations, your company should begin strategic planning as soon as possible to determine how it will address future compliance issues if compliance cannot be achieved or determined during SSM events.  EPA has not indicated whether it will exercise enforcement discretion for violations or whether significant penalties will immediately ensue.

Industry and/or EPA will likely question the validity of each emission standard set by EPA, as it is likely that emissions during SSM events were not considered when setting the current emission standards.  Industry may request that EPA evaluate emissions that would occur during reasonably foreseeable SSM events and establish appropriate maximum achievable control technology (MACT) standards for such events.  CAA Section 112(d)(3) describes that MACT for existing sources should be determined by either the “average emission limitation achieved by the best performing 12 percent of the existing sources… of 30 or more sources” or “the average emission limitation achieved by the best performing five sources …with fewer than 30 sources.”  Therefore, it would be necessary to determine what the emissions were during SSM events to accurately determine what the emission standard should be for each NESHAP subpart.

Begin planning now on how to comply with NESHAP emission standards during SSM events or consider obtaining legal advice as to how to mitigate the ramifications of potential noncompliance events if continuous compliance during SSM cannot be achieved.

1  Parts of 40 CFR 63.6(e)(1)(i), 40 CFR 63.6(f)(1); 40 CFR 63.6(h)(1).
2  EPA letter titled “Re: Vacatur of Startup, Shutdown, and Malfunction (SSM) Exemption (40 CFR 63.6(f)(1) and 63.6(h)(1))” by Adam M. Kushner, Director of the Office of Civil Enforcement, dated July 22, 2009.
3  68 Federal Register 32591.
4  67 Federal Register 16582.
5  68 Federal Register 32586.
6  71 Federal Register 20446.
7  40 CFR 63.6(e)(1)(i).