In order to determine whether equipment and processes that emit air pollutants are part of a major source for purposes of air permitting, companies must apply a three-factor test. Emission units which meet all of the following criteria are aggregated:

  1. Belong to the same industrial grouping (SIC Code);
  2. Are contiguous or adjacent; and
  3. Are under common control.

The interpretation of the third criteria, "common control", has varied over time and among different jurisdictions. In some cases, agencies found common control because economic or operational interconnectedness was deemed to establish a support/dependency relationship between facilities.

A recent letter from US EPA Assistant Administrator William Wehrum reevaluates this issue. In it, EPA asserts that the assessment of "control" should focus on the "power or authority of one entity to dictate decisions of the other that could affect the applicability of, or compliance with, relevant air pollution regulatory requirements." The letter also makes it clear that state and local authorities with approved permit programs have the primary responsibility to make source determinations.

The letter is available here on the EPA's website. An in-depth look at this policy update will be featured in an upcoming Trinity Environmental Quality ("EQ") article.

For assistance with your air permitting needs, contact the Trinity office nearest you by calling 800-229-6655 for more information.