The Utility Air Regulatory Group (UARG) was unsuccessful in its petition to overturn particulate matter (PM) provisions in EPA’s 2009 New Source Performance Standards (NSPS) for electric utility steam- generating units.  According to the U.S. Court of Appeals for the D.C. Circuit, several of the issues in UARG’s petition were not properly before the court because the EPA is still reconsidering them.  The court also disagreed with the legal arguments the UARG offered against other PM provisions in the NSPS.  

COMS and CEMS

The 2009 NSPS addressed two forms of PM—filterable, which is emitted from the stack as a solid; and condensable, which is emitted as a gas but turns to liquid after exiting the stack.  Filterable PM can be measured by a continuous opacity monitoring system (COMS) or a continuous emissions monitoring system (CEMS).  But neither a COMS nor a CEMS can measure condensable PM.  However, visual inspection can measure both filterable and condensable PM. 

The 2009 rule exempted units using PM CEMS from all opacity standards and monitoring provided they complied with an emissions standard for filterable PM of 0.03 pounds per million Btu (lb/MMBtu).  If a unit using a PM CEMS did not comply with the limit, the rule required it to either use a COMS or perform periodic visual inspections to comply with the opacity standard. 

Petition for reconsideration

In a petition to the EPA, the UARG asked the Agency to reconsider, among other things, its decision to limit the exemption from the opacity standard and monitoring requirements to units complying with the 0.03 lb/MMBtu emissions standard.  The EPA granted the reconsideration and followed in 2011 with a proposal that would establish a total (filterable plus condensable) PM emissions limit.  The Agency also proposed to add an affirmative defense to civil penalties for emissions exceedances caused by malfunctions. 

In comments on the proposal, the UARG asked that the EPA exempt certain boilers using CEMS from the opacity standard because CEMS are sufficiently accurate to ensure compliance with emissions standards.  The EPA followed in 2012 with a final rule that did not expand its 2009 exemption.

Public comment

In its ruling, the D.C. Circuit refused to rule on UARG’s reconsideration request to the EPA until the Agency acts on that request.  The court says the Clean Air Act is clear that only those objections to rules or procedures raised with reasonable specificity during the public comment period may be introduced for judicial review. 

Accordingly, the court did find that UARG’s comments on the 2011 proposal opened the door for judicial review.  Specifically, in its petition to the court, the UARG contended that continuing to subject boilers emitting more than 0.03 lb/MMBtu of PM to an opacity standard and opacity monitoring requirements, while exempting boilers emitting that amount or less, was arbitrary and capricious. 

But the court saw the logic of EPA’s approach.  The court noted that in its rulemaking, the Agency explained that sources emitting 0.03 lb/MMBtu or less of PM will operate with little or no visible emissions and, thus, an opacity standard is no longer necessary for these sources.  “Hence, for a source that is meeting this emission standard, no opacity standard is needed because any visible opacity will indicate improper operation,” said the court.

“By contrast,” added the court, “units emitting more than 0.03 lb/MMBtu of particulate matter ‘may have some visible emissions’ even if their particulate matter control devices are operating properly.  Accordingly, the agency reasonably concluded that a unit emitting more than 0.03 lb/MMBtu should remain ‘subject to an opacity limit’ and ‘use a COMS or perform periodic visual inspections to comply with the opacity standard’ to verify that the pollution control and monitoring systems are operating properly.”

Affirmative defense 

Also in its ruling, the D.C. Circuit denied a Texas petition to substitute its own affirmative defense provision for the federal affirmative defense provision provided by the EPA.  The court explained that Texas had raised this issue in a petition for reconsideration submitted to the Agency.  As with the UARG situation, the court refused to rule on a petition the EPA is still reconsidering. 

UARG v. EPA