Trihydro employee using an OGI camera
NSPS OOOOa Regulatory Forecast

New Source Performance Standard (NSPS) Subpart OOOOa, originally published in 2016, has experienced multiple amendments in its short history, and additional changes are expected in 2021 and 2022.

OOOOa Background

OOOOa establishes emissions standards and compliance requirements for affected crude oil and natural gas production operations, with a focus on volatile organic compounds (VOCs) and methane emissions. Since the original rule promulgation, OOOOa has had several modifications and has been subject to multiple lawsuits and court determinations.

This discussion focuses on the most recent 2020 amendments and anticipated changes that may take place in 2021 and 2022.

September 2020 Final Rule Amendments

The U.S. Environmental Protection Agency (EPA) issued two final rules amending OOOOa in September 2020. The first amendment was published on September 14, 2020, and is generally referred to as the technical rulemaking. The second amendment was published on September 15, 2020, and is commonly referred to as the reconsideration rulemaking.

Key changes in the September 14 technical rule included:

  • Removal of greenhouse gases, specifically methane, as covered pollutants.
  • Removal of the transmission and storage source category as covered affected facilities.
  • Adopting an interpretation of the Clean Air Act (CAA) Section 111 under which the EPA, as a basis for promulgating NSPS for certain air pollutants, must determine that the pertinent pollutant causes or contributes significantly to dangerous air pollution. EPA documented in the rule preamble that prior versions of OOOOa did not adequately make this determination for methane as a greenhouse gas pollutant.

The September 15 reconsideration rule resulted from EPA’s response to several petitions for reconsideration and addressed specific issues brought up by petitioners. Some of the most notable changes in the reconsideration rule included:

  • Addressing fugitive emission requirements for low production (less than 15 BOE/day) well sites
  • Establishing a process to request an Alternative Means of Emissions Limitation (AMEL) for facility monitoring requirements
  • Establishing that a well site pneumatic pump exemption due to inability to reroute to control device applies to all (not just greenfield) well sites
  • Eliminating the requirement for a professional engineer to certify the adequacy of the design of the closed vent system
  • Allowing the separator to be nearby (not onsite) and ready to use during well completions
  • Updated and clarified a change in the capital expenditure calculation (for the Y value, replacement cost percentage) for natural gas plants
  • Simplified some of the fugitive monitoring recordkeeping requirements
  • Reduced fugitive monitoring for well sites and compressor stations to semiannual

Now What? Trihydro’s Regulatory Forecast

On January 20, 2021, the new Administration issued an Executive Order to review numerous rulemaking activities over the past several years, including an evaluation of the September 15, 2020, OOOOa rule.

Although the September 14, 2020, rule is not included in the Executive Order, other actions are underway. In late March 2021, both the U.S. House and Senate introduced resolutions under the Congressional Review Act (CRA) targeting the September 14, 2020, rule for repeal. If both congressional bodies pass these resolutions (by a simple majority) and they are signed by the President, the September 14 rule will be repealed and the changes made in that rule will be eliminated as if they had never been published. Although the CRA prohibits future substantially similar rulemaking, it may be limited to only the repealed language versus OOOOa in its entirety.

Although regulatory forecasts always involve a degree of uncertainty, it appears likely the CRA resolutions will pass, reestablishing methane as a regulated pollutant and once again including the transmission and storage sectors as affected facilities under OOOOa. Importantly, methane and greenhouse gas will also once again be determined to be a pollutant that causes or contributes significantly to dangerous air pollution. Notably, the September 15, 2020, rule will not be repealed by this action, and its provisions will remain in effect for the time being.

It is anticipated EPA will embark upon two rulemakings that may be proposed later in 2021 and could be finalized as soon as the 2nd or 3rd calendar quarters of 2022. Both rulemakings will go through the Administrative Procedures Act notice and comment process (i.e., the typical rulemaking process).

  • The first proposal (consistent with the January 2021 Executive Order) will focus on changes made in the September 15, 2020, rule, as well as the current OOOOa rule in general that will likely increase the stringency of controls and requirements on affected facilities. Recent state regulatory changes, such as Colorado’s pneumatic controller requirements and New Mexico’s flaring requirements, may be considered as part of those changes.
  • The second proposal, which is contingent on the passage of the CRA resolutions, will likely target existing source regulation under Section 111 of the CAA. The scope of this rulemaking is less clear, although it may be similar to current OOOOa requirements.

Learn More

Trihydro is following OOOOa regulatory movements closely and we have regulatory experts on staff who can help you evaluate what changes may mean for your operations and compliance efforts.

Contact Us

Jay Christopher
Senior Scientist Specialist, Englewood, Colorado

Jay has over 40 years of environmental experience. Since 1990, he has specialized in air quality issues and permitting programs affecting a broad range of facility operations, with hands-on experience in both corporate headquarters and facility regulatory settings, as well as in the environmental consulting world. Jay has managed the environmental compliance program and environmental professional staff for a major refinery’s downstream businesses and is involved in regional air quality issues and national trade groups.

Did you find this information useful? Click the icons below to share on your social channels.

facebook twitter linkedin
Other News


Receive the latest technical and regulatory updates in your inbox.