The Pennsylvania Department of Environmental Protection submitted technical guidance documents for public review and comment to the Pennsylvania Bulletin on Tuesday, October 12. The technical documents concern new sources of stationary air emissions and whether the “air aggregation” determinations are applicable for the issuance of permits. The problem with the “air aggregation” determinations arise from the potential aggregation of two or more stationary sources into a single source, subjecting the sources to additional and costly permitting requirements. Stationary sources of air pollution are subject to permitting under Prevention of Significant Deterioration (PSD), Pennsylvania’s nonattainment New Source Review (NSR) and Title V programs, which differ depending on whether sources are treated as aggregates or single entities.
State air quality regulators have had a history of altering the definition in the Air Pollution Control Act, (35 P.S. § 4001 et seq.) to mean interdependent. This determination has resulted in the aggregation of sources, subjecting them to a greater degree of stringency for air permitting purposes. The language of the Act refers to the distance or spatial relationship between two sources as “contiguous” or “adjacent”. The distinction between interdependence and contiguous or adjacent is the source of the controversy that has led to the submission of technical documents for the public’s comment.
Part of the problem is the ambiguity of the definition of what is “contiguous” or “adjacent” and what is not. According to Pennsylvania’s regulations, “contiguous” is defined as, “sharing an edge or boundary; touching; neighboring, adjacent, connecting without a break”. Analogous to contiguous, is the definition of “adjacent”, defined as, “close to; lying near, next to; adjoining”. This ambiguity has prompted other states including Oklahoma, Texas, and Louisiana to adopt a quarter-mile rule of thumb, which explicitly states that “facilities operating within a quarter-mile or less of each other shall be defined as aggregate”. The technical guidance document published by the PADEP includes the above statement, but does not recommend that its Air Quality permitting staff use it as a determining factor. Rather, the document suggests permitting staff adopt a “common sense” approach of whether a facility is functionally operating as a single source or as an aggregate. The PADEP released a statement on Tuesday, October 13 authorizing all Air Permitting staff to operate under the language of the technical guidance document, which includes the above mentioned statements.