US EPA periodically issues compliance advisories and enforcement alerts that highlight the agency’s enforcement efforts related to specific regulations and regulatory provisions. One recent EPA enforcement alert targets air emissions from stationary engines subject to the RICE NESHAP under 40 CFR Part 63, Subpart ZZZZ and new source performance standards in 40 CFR Part 60, Subparts IIII and JJJJ. Stationary engines are widely used by a variety of industries, including the oil and gas and energy industries, and support equipment like pumps, compressors, and generators.

The enforcement alert states that noncomplying stationary engines emit excess volatile organic compounds (VOCs) and ozone precursors (e.g. NOx), which contribute to ground-level ozone and overall poor air quality. Common violations include a failure to retrofit existing engines with requisite pollution controls and missed testing. To resolve the alleged violations, US EPA has required equipment upgrades and replacement and has collected six-figure civil penalties in some cases.   

US EPA includes several recommendations to ensure compliance in the enforcement alert. Notable recommendations include:

  • Review engine specs to identify the applicable regulations (e.g. Subpart ZZZZ, Subpart IIII, Subpart JJJJ).  
  • Assess applicable emission and operating limits and recordkeeping and reporting requirements.
  • Evaluate options for upgrading or replacing older engines with newer engines or converting to the power grid.

While stationary engines may appear to be marginal contributors to air pollution compared to other sources, US EPA’s enforcement alert highlights the need for companies to evaluate their stationary engines to ensure compliance. This is particularly true for oil and gas, energy, and mining companies that appear to be US EPA’s primary enforcement targets in this context. Companies in these industries may tend to focus compliance efforts on seemingly more significant sources of air pollution, but the stationary engine enforcement alert should serve as a reminder to take a comprehensive approach to evaluating and ensuring compliance with applicable air regulations.