Clean Air Act (42 U.S.C. § 7401 et seq.)

The CAA is the primary federal statute for controlling air pollution in the United States.  Both stationary sources of air pollution (e.g., factories, power generation facilities, etc.) and mobile sources (e.g., automobiles, trucks, backhoes) are regulated under the Act.  As a result, the requirements of the CAA may apply to both the construction and operation of a pipeline infrastructure project, with the applicability of various requirements determined by a variety of factors, including the nature of the pipeline and associated infrastructure, the construction techniques used, and the existing air quality in the vicinity of the project. 

With respect to natural gas pipeline operations, a pipeline itself generally does not have any significant air emissions associated with its operation; while there may be what are termed “fugitive emissions” from a pipeline, such emissions are generally very minor in nature and typically are not subject to the requirement to obtain a permit.  The element of pipeline infrastructure projects that most commonly triggers the need for a CAA permit for operations is compressor stations.  Such stations may trigger requirements under several CAA programs, including the New Source Review (NSR) and Prevention of Significant Deterioration (PSD) program and the permitting program for major stationary sources under Title V of the CAA. 

The NSR program applies to new source construction and proposals to conduct major modifications of existing industrial  facilities that are located in “non-attainment” areas (i.e., regions with poor air quality that do not satisfy the National Ambient Air Quality Standards), while the “Prevention of Significant Deterioration” requirements apply to project proposals that are located in areas which are in “attainment” with applicable National Ambient Air Quality Standards (i.e., ambient air quality in the region surrounding the new or modified source complies with the national standards).  NSR and PSD requirements apply to facilities that are considered “major sources” of air pollutants because they would emit pollutants in excess of certain defined thresholds.  Such facilities must undergo a review of potential air emissions and proposed air pollution control measures prior to construction of the facility. 

In addition, Title V of the CAA requires that operating permits be obtained for “major sources” of air pollutants, which for purposes of Title V is defined to include stationary sources that have the potential to emit 100 tons per year of any regulated air pollutant, 10 tons per year of any one hazardous air pollutant or 25 tons per year of any combination of hazardous air pollutants.  Title V permitting requirements may also apply to other sources of air emissions, including sources that are subject to certain standards governing emissions of hazardous air pollutants.  In most cases, Title V permits are issued by state air pollution control authorities pursuant to state programs that comply with federal standards. 

The construction of pipelines and related infrastructure can also trigger a variety of CAA requirements due to air emissions – principally diesel emissions – from equipment used in the construction of the project.  Depending on the magnitude of construction-related emissions, such emissions could trigger the need for NSR or PSD review.  In addition, a pipeline may require a review for general conformity with a State Implementation Plan (SIP), i.e., a state plan for achieving compliance with various CAA requirements governing overall air quality.  These SIPs may establish enforceable emission limitations for particular emission sources, permitting programs for the construction of new or modified air pollutant-emitting facilities, and other control measures applicable to emission sources within the state to ensure that the National Ambient Air Quality Standards will be achieved and maintained within each air quality control region within a state.  The Commission may be required to determine that the construction and operation of a proposed pipeline would be consistent with the SIP of the state within which the pipeline would be located.