Sulfur Dioxide Consent Decree Approved by Court Over Objections by State Air Agencies

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By Patrick Ambrosio

March 3 — A federal district court judge approved a consent decree that will allow the Environmental Protection Agency to take a phased approach to making designations under the 2010 national ambient air quality standards for sulfur dioxide, despite objections from several state environmental agencies.

The consent decree, approved March 2 by the U.S. District Court for the Northern District of California, settles a lawsuit filed by the Sierra Club and the Natural Resources Defense Council over the EPA's failure to make additional attainment and nonattainment designations for the standards.

The agency in 2013 designated 29 areas in 16 states to be in nonattainment, but delayed its decision on the rest of the country due to inadequate air monitoring.

Under the agreement, the EPA will promulgate rules making area designations at three separate times between July 2016 and Dec. 31, 2020.

Several state environmental agencies, including Arizona, Kentucky, North Carolina and North Dakota, had alleged that the consent decree would violate the Clean Air Act, but the court found that the statute doesn't compel the EPA to make unclassifiable designations for the undesignated areas.

Puts ‘Long Overdue' Schedule in Place 

Mary Anne Hitt, director of the Sierra Club Beyond Coal Campaign, said in a March 3 statement that the settlement puts a “long overdue” schedule in place for the EPA to address sulfur dioxide pollution.

An attorney for the states that opposed the consent decree couldn't be reached for comment March 3.

Under the approved consent decree, the EPA will have until July 2016 to make nonattainment designations for areas that have violated the sulfur dioxide standards based on three years of air quality monitoring data and contain stationary sources that meet a certain emissions threshold.

The emissions threshold specified in the consent decree is sources that emitted more than 16,000 tons of sulfur dioxide in 2012 or emitted more than 2,600 tons of sulfur dioxide and had an average emission rate above 0.45 pounds per one million British thermal units of heat input in 2012.

2017, 2020 Deadlines Imposed 

The agency will then have until Dec. 31, 2017, to issue designations for remaining undesignated areas that fail to install an adequate sulfur dioxide monitoring network by Jan. 1, 2017.

The monitoring network specifications are referenced in a May 2014 EPA proposed rule (RIN 2060-AR19) that would require state and tribal air agencies to provide the EPA with data to characterize current air quality in areas with large sources of sulfur dioxide emissions if the areas don't have sufficient air quality monitoring in place.

The EPA will have until Dec. 31, 2020, to issue area designations for all remaining undesignated areas, which is enough time for areas that install adequate monitoring networks to gather three years of data.

States Opposed Agreement 

The court rejected state arguments that the agreement between the EPA and the environmental groups would violate section 107(d) of the Clean Air Act, the section that requires the EPA to proceed with area designations no more than three years after a national ambient air quality standard is revised.

The states, in a May court filing, said the phased approach “far exceeds” Clean Air Act mandatory deadlines and “reads out” of the law the unclassifiable designation that the EPA is to use when it lacks sufficient information to make a designation of attainment or nonattainment with an air quality standard.

The consent decree also “specifically dictates” the types of sources located in a certain area that the EPA should first consider for designation, which goes beyond merely setting a timetable for EPA action, according to the states.

Binding Schedule Called Appropriate Remedy 

The court ruled that, in a deadline suit, the appropriate remedy by the court is to set a binding schedule for the EPA to take action, while maintaining the agency's discretion to determine whether an area is in attainment, nonattainment or unclassifiable.

The district court also found that the proposed consent decree is procedurally fair, citing both the public comment period opened by the EPA in June 2014 and the settlement negotiations, which the states participated in as intervenors in the litigation.

Clint Woods, executive director of the Association of Air Pollution Control Agencies, pointed to comments submitted to the EPA by the Nevada Department of Conservation and Natural Resources Division of Environmental Protection when asked about the practical effect of the phased approach for area designations.

Five Reasons Outlined 

In those comments, filed in response to the proposed consent decree, Nevada outlined the following five reasons why an unclassifiable designation would be preferable to a delay in the EPA making any designation:

• unclassifiable areas are traditionally treated as being in attainment, meaning that a state wouldn't have to prepare a state implementation plan or require more stringent pollution controls on regulated sources;

• an unclassifiable designation traditionally allows states to utilize resources to deploy monitoring networks near population centers, rather than in rural areas;

• a designation provides certainty for existing and potentially new industries;

• the 2020 deadline for finishing all area designations won't occur until after the EPA is required under the Clean Air Act to reevaluate and possibly revise the national standards for sulfur dioxide; and

• the EPA's proposed data requirements rule for the sulfur dioxide standards seeks to use modeling, which Nevada described as a predictive tool that isn't appropriate for making area designations.


To contact the reporter on this story: Patrick Ambrosio in Washington at

To contact the editor responsible for this story: Larry Pearl at

The consent decree in Sierra Club v. McCarthy is available at