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MACT SSM Exemption is Vacated

Posted: January 19th, 2012

Author: All4 Staff 

What happened?

On December 19, 2008, the U.S. Court of Appeals for the D.C. Circuit (Court) issued a decision vacating the Startup, Shutdown, and Malfunction (SSM) exemption provisions of the Federal National Emission Standards for Hazardous Air Pollutants (NESHAP) for Source Categories.  These NESHAP regulations require the use of Maximum Achievable Control Technology (MACT) for minimizing hazardous air pollutant (HAP) emissions from regulated sources. The rules, including the SSM exemption provisions, are codified at 40 CFR Part 63 and were originally adopted by U.S. EPA in 1994.

The SSM exemption provisions included in the MACT rules were based on U.S. EPA’s consideration of a source’s “general duty” to minimize emissions during SSM events.  The general duty provision was previously established under the Standards of Performance for New Stationary Sources (NSPS) rules.  In vacating the exemption, the Court decided that the general duty to minimize emissions during an SSM event is inconsistent with Section 112 of the Clean Air Act (CAA) because the CAA requires that a Section 112 standard must apply continuously.

How does the SSM exemption work?

The SSM exemption provisions give sources that are subject to a MACT standard a conditional exemption from continuous compliance with the applicable emission standard during SSM events.  In order to utilize the exemption, sources are required to comply with the general duty to reduce emissions to the greatest extent possible consistent with safety and good air pollution control practices during an SSM event.

To satisfy the SSM exemption provisions, sources developed SSM plans that detailed possible SSM events, included procedures that would be followed to minimize emissions during such events, identified corrective measures for addressing malfunctions, and summarized the recordkeeping and reporting procedures that the sources would use to document compliance with the exemption provisions.  Sources that are subject to the SSM provisions are required to submit semi-annual reports of SSM events to permitting authorities.

What did the Court say?

The Court decision is relatively brief and can be viewed here.  Although the SSM provisions were not initially challenged by environmental groups when the rule was issued in 1994, the Court held that the changes that U.S. EPA made to the original rule in recent years effectively opened it to challenge.  The Court concluded that “the SSM exemption violates the CAA’s requirement that some Section 112 standards apply continuously” to affected sources and that “the general duty is not a Section 112-compliant standard.”

What is the immediate affect of the vacatur?

It is mid-January now and many facilities that are subject to MACT rules are in the process of preparing their semi-annual reports, including SSM reports.  As sources prepare these reports, a recurring question is how the Court’s decision to vacate the SSM exemption affects the recently ended reporting period.  For example: Is it necessary now to report exceedances during all events, including those where the SSM plan was followed, in my current report?  The answer is that the vacatur is not immediately effective and does not take effect until the date that the Court issues its mandate.

There is a minimum 45-day period beginning on the date the Court issued its decision (i.e., December 19, 2008) during which U.S. EPA or an intervenor can file for a rehearing.  If a rehearing is granted, the mandate can be stayed for an even longer period.  It is likely that U.S. EPA will request an extension to afford the new Administration time to get up to speed on the matter.  Therefore, for now it appears to make the most sense for sources to prepare any current SSM reports consistent with previous submittals.  Then it’s time to sit back and watch how this one will play out because if and when it does take effect, any exceedance of a MACT standard will be a violation, including those that occur during SSM events.


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