EPA Issues New Standards of Performance and Emission Guidelines

“On January 20, 2021, President Joe Biden issued an Executive Order titled ‘Protecting Public Health and the Environment and Restoring Science to Tackle the Climate Crisis,’ which directs the EPA to propose a rulemaking to reduce methane and volatile organic compound emissions in the oil and natural gas sector by suspending, revising, or rescinding the previously issued New Source Performance Standards and propose new regulations to establish standards of performance for methane and volatile organic compound emissions from the exploration and production, transmission, processing, and storage segments by September 2021. The EO also directs the EPA to propose new regulations to establish emission guidelines for methane and volatile organic compound emissions from existing operations in the exploration and production, transmission, processing, and storage segments by September 2021.

The purpose of this action is to review the existing NSPS and propose new requirements and propose new emission guidelines for existing sources in order to meet the requirements set forth in the Executive Order1.”

By Foster Voelker, Director of Engineering, William E. Williams Valve Corporation

The EPA’s final rule, released on December 2, 2023, aims to significantly reduce methane and other harmful emissions from U.S. oil and natural gas operations. This includes updated standards for new, modified, and reconstructed sources, as well as guidelines for existing sources. The final rule incorporates New Source Performance Standards (NSPS) and Emission Guidelines (EG), as outlined in the executive order (EO), targeting emissions from the oil and gas sector. It focuses on reducing methane emissions, a potent greenhouse gas, along with emissions of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs). The rule emphasizes phasing out routine flaring, requiring regular leak monitoring, and leveraging innovative technologies. It aims to prevent 58 million tons of methane emissions from 2024 to 2038, alongside significant reductions in VOCs and toxic air pollutants. The EPA claims that the rule reflects extensive industry and public feedback, offering flexible and innovative solutions while setting rigorous standards.

Impact on Air Quality

The final NSPS OOOOb and EG OOOOc are projected to substantially reduce methane, VOC, and HAP emissions from the oil and gas sector. The EPA projects that from 2024 to 2038, the final rule will reduce approximately 58 million tons of methane emissions, which is equivalent to about 1.5 billion tons of CO2. Additionally, it is expected to reduce 16 million tons of VOC emissions and 590 thousand tons of HAP emissions from affected facilities.

Cost and Economic Analysis

The cost implications of the rule are significant. The estimated average annual regulatory compliance cost over the 2024 to 2038 period is about USD $1.5 billion, using varying discount rates. These costs encompass the expenses associated with implementing and maintaining the required emissions control technologies. However, the EPA argues these costs are counterbalanced by the environmental and health benefits derived from reduced emissions.

Specific Equipment and Technologies

The rule covers a wide range of equipment and technologies, including storage vessels, associated gas, pumps, and various compressors. It also includes provisions for advanced methane detection technologies. These technologies allow for periodic screening or continuous monitoring of fugitive emissions. This advanced detection can identify super-emitter events sooner and more effectively. Equipment impacts include:

Zero-Emitting Controllers

The rule requires the installation of zero-emitting controllers for certain types of equipment, particularly for process controllers in the NSPS OOOOb. For sites outside of Alaska, all process controllers are required to achieve zero emissions of volatile organic compounds (VOCs) and greenhouse gases (GHGs), specifically methane. This standard is applicable to both new and existing sites. Compliance can be attained through several methods: utilizing process controllers that are not driven by natural gas, thus not being classified as affected facilities; routing vapors from natural gas-driven process controllers through a closed vent system to a process where they can be controlled; or using self-contained natural gas-driven process controllers, among other methods, to ensure the numerical standard of zero emissions for methane and VOCs is achieved .

Open-Ended Valves or Lines

Each open-ended valve or line must be equipped with a closure device (e.g., cap, blind flange, plug, or a second valve). This device must seal the open end at all times except during operations requiring process fluid flow through the open-ended valve or line. This requirement aims to prevent unintended emissions from these components.

Monitoring and Control Devices

Control Valve Stations (CVS) must be monitored bimonthly using Optical Gas Imaging (OGI) or quarterly using EPA Method 21 if this alternative is used. This ensures regular checks and maintenance of these components to minimize emissions. Control devices used to comply with equipment leak provisions must adhere to specific requirements detailed in the rule. This includes standards for design, operation, and maintenance to ensure they effectively control emissions.

Pressure Relief Devices

Pressure relief devices are required to be monitored within five days after a pressure release to ensure the device has reseated properly. This is crucial for maintaining the integrity of these devices and ensuring they function correctly to prevent emissions.

Definition of Repaired Equipment

The EPA proposed that the definition of “repaired” for equipment means that the equipment is adjusted, replaced, or otherwise altered to eliminate leaks. Additionally, the repaired equipment must be re-monitored to verify that emissions are below the leak definition. This ensures that repairs are effective in reducing emissions.

Use of Low-E Equipment

The rule explains that repairs of valves can include replacement with low emission (Low-E) valves, Low-E valve packing, or the use of a drill-and-tap with Low-E injectable material. This is referred to as “Low-E equipment.”

However, the rule does not mandate the replacement of all leaking equipment with Low-E equipment. Operators are not required to use Low-E equipment if they can demonstrate that it is not technically feasible. Considerations for deeming a Low-E solution technically infeasible include cases where the Low-E technology is unsuitable for the valve’s intended use, retrofit requirements (like re-piping or space limitations), commercial unavailability for specific types of valves, or issues with certain instrumentation assemblies. Operators must annually report instances where it was infeasible to use Low-E technology for repairs, including the reasons for infeasibility.

Specifications and Guarantees of Low-E Equipment

Low-E equipment indicates that the equipment adheres to established industry standards for low emissions. Low-E valves and packing are defined as follows: A Low-E valve is a type of valve for which the manufacturer provides a guarantee that it will emit fugitive emissions at a rate of less than 100 parts per million by volume (ppmv) over the first five years. Similarly, Low-E packing, used in these valves, adheres to the same emissions standard as per the manufacturer’s warranty.

Additionally, there is Low-E injectable packing, which is specifically designed for drill-and-tap valve repairs, and also comes with a manufacturer’s guarantee regarding emission levels. The EPA outlines that Low-E equipment meets the specifications of API 622 or API 624.

Overall Emission Reduction

The NSPS OOOOb and EG OOOOc standards aim for a significant reduction in methane emissions. From 2024 to 2038, they are projected to achieve a 79% reduction in methane emissions from the sources covered under these standards. This represents a major step in reducing emissions from one of the largest U.S. industrial sources of methane, leading to substantial climate and environmental benefits, as well as positive impacts on human health.


The final rule set by the EPA marks a critical step towards mitigating the impact of the oil and gas industry on the environment and public health. By targeting equipment emissions, the rule addresses one of the key sources of air pollutants in this sector. The anticipated reduction in methane, VOC, and HAP emissions over the next 15 years underlines the rule’s potential to contribute significantly to cleaner air and a healthier environment. Moreover, the inclusion of advanced detection technologies and the focus on energy-efficient emissions control highlight the rule’s approach to balancing environmental goals with economic considerations. The 79% projected reduction in methane emissions underscores the rule’s potential for significant climate benefits.


Foster Voelker II attended the University of Houston, receiving a degree in Mechanical Engineering. After graduation, Foster Voelker began his career as a valve engineer for a large commodity valve manufacturer. He is the Director of Engineering for William E. Williams Valve Corporation.

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Shopia Ketheeswararajah is a feature editor contributing to Pump Engineer, Stainless steel World Americas, Hose and Coupling World, and other related print & online media.