EPA Repeals “Once In, Always In” for Major Sources

EPA Report on NSR and NAAQS Programs
October 30, 2017
EPA Proposes Amendments to 2016’s NSPS OOOOa
September 12, 2018

January 25, 2018

The EPA has issued a guidance memo (source link) that has reversed the “once-in-always-in” interpretation of when a source may avoid Maximum Achievable Control Technology (MACT) standards for “major sources” of hazardous air pollutants (HAPs) under Section 112 of the Clean Air Act (the Act).

As defined by the Code of Federal Regulations (CFR), a major sources means any stationary source or group of stationary sources located within a contiguous area and under common control that emits or has the potential to emit considering controls, in the aggregate, 10 tons per year or more of any hazardous air pollutant or 25 tons per year or more of any combination of hazardous air pollutants, unless the Administrator establishes a lesser quantity, or in the case of radionuclides, different criteria from those specified in this sentence.

For over two decades, the EPA has maintained the position that MACT standards and requirements (found under 40 CFR 63) are application to any facility whose Potential to Emit (PTE) surpassed the “Major Source” thresholds on or after the effective date of the applicable MACT.

The new guidance memo released this week strays from this established interpretation of Section 112 of the Clean Air Act by stating “a major source that takes an enforceable limit on its PTE and takes measures to bring its HAP emissions below the applicable threshold becomes an area source, no matter when the source may choose to take measures to limit its PTE.” Area sources are less stringently regulated, as they are not subject to MACT standards.

Affected clients should proceed with caution in relying on the reversed policy as some MACT standards will require regulatory changes as part of the implementation. This process alone is forecast to take between 12 and 18 months. Furthermore, this reversal in policy will be subjected to litigation. With time these issues will be settled and reliance on the memo may be possible with greater long-term certainty.

If you have any further questions, please contact Waid Environmental.