New EPA Regulations Bring Massive Changes to Oil & Gas Industry

March 14, 2024

On Friday, March 8, 2024, the United States Environmental Protection Agency (EPA) released what many consider to be the most comprehensive regulation for the oil and gas industry. The New Source Performance Standards Subpart OOOOb/c targets both new and existing facilities in the oil and gas industry. For these regulations, the term “new” refers to any well pad, centralized tank battery, compressor station, or processing plant constructed or modified on or after December 6, 2022. The effective date for subpart OOOOb is May 7, 2024, and sources subject to the regulation need to be in compliance by this date. Certain sections of OOOOb have a longer compliance period, which will be discussed later.

The next important aspect of OOOOb is what parts of your facilities are subject to it. Like its predecessors, OOOOb affects storage vessels, pneumatic controllers, reciprocal compressor rod packing, centrifugal compressor seals, pneumatic pumps, and fugitive components. However, the required standards under OOOOb are much more stringent than its predecessors. We’ll go over the standards for each section in the following paragraphs.

Process Controllers

Process controllers, formerly called pneumatic devices, now must meet a zero-emission standard. This is a large shift from previous standards, subparts OOOO and OOOOa, which had venting limitations on continuous-bleed controllers. Under OOOOb, both continuous- and intermittent-bleed controllers must meet the zero-emission standard. Operators can meet this requirement in one of three ways. The first option is to switch the controllers to a non-natural gas-driven source like compressed air, electric, or nitrogen. For the second option, an operator can use self-contained natural gas-driven controllers that do not vent. If an operator chooses to use natural gas controllers, they must be monitored for leaks every quarter. The final option is to route the vent of natural gas-driven process controllers through a closed-vent system to a process like a fuel system or similar system to reuse the gas. These standards apply to all controllers installed at any facility after the triggering date of the regulation (December 6, 2022), not just facilities constructed after December 6, 2022. If a facility replaces more than half the existing controllers at a facility after the effective date, then all controllers at that facility are now subject. Unlike other sectors, operators have an additional year (until May 7, 2025) to get into compliance.

Pneumatic Pumps

Gas-driven pneumatic pumps also must adhere to the zero-emission standard depending on two factors: the availability of on-site electricity and the number of diaphragm pumps. If the facility has on-site electricity, all pneumatic pumps must meet the zero-emission standard by one of the methods listed above in the process controllers section. Sites without access to electricity that also have three or more gas-driven diaphragm pumps must meet the zero-emission standard. If a facility has less than three diaphragm pumps and no on-site electricity, the vents from the pumps must be routed to either a vapor recovery system or a 95 percent control device if one is already installed at the facility. Like the process controllers requirements, facilities subject to the pneumatic pump requirements have until May 7, 2025, to get into compliance.

Centrifugal Compressors

In OOOO and OOOOa, centrifugal compressors subject to the rules had to route the vents of any wet seals to a control device or capture the emissions in a recovery unit; dry-seal units had no requirements under OOOO or OOOOa. Under OOOOb, both wet- and dry-seal centrifugal compressors have limits on the seal flow rate and must perform annual monitoring to ensure compliance with these limits.

Reciprocating Compressors

Similar to their centrifugal counterparts, reciprocating compressors had a simple requirement under OOOO and OOOOa: replace the rod packing every 36 months or 26,000 hours of operation. OOOOb places a flow limit on the packing vents and annual monitoring. Operators do have the option to forgo the monitoring if they change the rod packing every 8,760 hours of operation.


The first major change under OOOOb for tanks is the change to the definition; previously, tanks were each an individual source for determining the emissions. The new rule defines a storage vessel affected facility as a single tank or group of tanks manifolded together where the total emissions are used for determining applicability. Storage vessels under OOOOb have the same volatile organic compound (VOC) limit as OOOOa, but the new rules also establish a methane limit for requiring controls.


Fugitive emission requirements were introduced by OOOOa. The new rules expand the definitions and requirements for facilities. Whereas previously fugitives applied to well pads and compressor stations, OOOOb adds additional types of facilities, and the requirements vary by what category your facility falls into. In addition to the optical gas imaging (OGI) or Method 21 surveys, operators will also have to perform audio, visual, and olfactory (AVO) surveys — the frequency of each survey depends on what type of facility. Well pads are broken into four categories: single wellhead, multi-wellhead only, small well sites, and well sites with major equipment. For the new facility types, centralized production is intended for tank batteries or facilities that receive gas and/or liquids from multiple well pads. Compressor station requirements for OGI are similar to OOOOa but now have the addition of the AVO surveys. The frequency of the surveys increases with the complexity of the equipment.

Liquids Unloading

Liquids unloading is one of the new affected facility types that was added under OOOOb. The EPA is requiring operators to develop best practice plans to minimize the emissions from liquids unloading. These requirements only apply to events that are not routine maintenance or require additional rigs, so workovers and swabbing with a rig are not affected activities.

Associated Gas

Another part of the industry that is targeted under OOOOb is associated gas. New wells completed after May 7, 2024, will have to either route the associated gas to a sales line, recover the gas to reuse on-site, or reinject the gas into a well. Wells turned in line after December 6, 2022, but before May 7, 2024, can route the associated gas to a 95 percent control device.

Control Devices

OOOOb institutes requirements for operators to ensure control devices are meeting the destruction efficiency required. Operators will have to not only continuously measure or calculate the flow rates of gas to the combustion control devices but also take samples initially and then three times every five years to determine the BTU content of the gas going to these units.


All of these changes are just the beginning of the comprehensive changes from this regulation. In addition to OOOOb, the EPA also introduced OOOOc to regulate sources constructed before December 6, 2022. OOOOc is a guidance document for states to pass their own rules and implement them into their State Implementation Plans. States have 24 months to submit their plans to the EPA to demonstrate compliance. States have the option to make their rules equal to the provisions of OOOOc or more stringent.

CEC will continue to follow updates to regulations that affect our clients. Contact us for more information or an evaluation of your facilities’ applicability. If you have any questions regarding the new regulations or would like an evaluation of your facilities’ applicability, please contact our experts:

Leah Blinn 

Leah Blinn | Vice President, Corporate Air Quality Practice Lead, 412.249.1607




David Morris | Project Manager II, 412.275.2949

About the Author

David Morris

David Morris is a Project Manager II in CEC's Air Quality practice at our Pittsburgh office. His areas of expertise are in environmental and air quality compliance between the oil & gas and manufacturing sectors.

Want more content like this?


Post a Comment

Your email address will not be published. Required fields are marked *