The United States Environmental Protection Agency (EPA) is proposing targeted revisions to the 2024 gasoline distribution air rules covering affected facilities under National Emission Standards for Hazardous Air Pollutants (NESHAP) Subparts R and BBBBBB (6B), as well as bulk gasoline terminals under New Source Performance Standards (NSPS) Subpart XXa.
EPA finalized the gasoline distribution technology review and new bulk gasoline terminal NSPS on May 8, 2024. Following three industry petitions for reconsideration, EPA granted reconsideration in February 2025 and published a proposed reconsideration rule on September 28, 2026. The agency is requesting comments only on the issues specifically addressed in this rulemaking. EPA states that the reconsideration is intended to provide compliance flexibility and reduce burden without changing the stringency of the underlying VOC and HAP emission standards. Comments are due November 12, 2026.
While EPA states that the proposed changes would not alter the underlying VOC and HAP emission standards, the revisions could affect how facilities demonstrate compliance, conduct monitoring, document inspections, and manage LDAR programs. Facilities have an opportunity to review the proposed changes and provide input before the rule is finalized.
What is EPA Proposing for NSPS Subpart XXa and NESHAP Subparts R and 6B?
The reconsideration focuses largely on how facilities demonstrate and document compliance. EPA’s proposed revisions fall into four primary areas:
- LDAR and Leak Monitoring Requirements: Several proposed revisions would affect leak detection and repair programs, including how certain projects trigger NSPS Subpart XXa requirements, implementation timelines, instrument monitoring frequency, and procedures for identifying and responding to leaks. EPA is also seeking feedback on annual instrument monitoring requirements and potential alternatives for bulk gasoline plants and pipeline pumping stations.
- Thermal Oxidizers (TO) Systems and Flare Compliance Requirements: To make compliance demonstrations more representative and less burdensome, EPA has proposed updates to requirements for thermal oxidizers and flares. The revisions would retain net-heating-value (NHV) controls while updating the diameter calculation for multi-burner systems, adding maximum air-assist settings and daily checks, allowing 14 NHV grab samples to be collected at intervals of at least 20 minutes, and simplifying certain recordkeeping requirements. For units subject to the 10 or 35 mg/L limits, EPA is also co-proposing either performance testing with a 3-hour rolling temperature limit or a fixed 400-degree Fahrenheit mid-stack minimum evaluated every five minutes.
- Vapor Recovery Unit (VRU) Systems and Monitoring Requirements: Among the proposed changes for VRU systems is a return to the historical six-hour rolling average for concentration limits. The rule would replace the prescriptive “previous 10 cycles” approach used during continuous emissions monitoring system (CEMS) downtime with a submitted, site-specific alternative monitoring plan. Emission limits would continue to apply during carbon bed regeneration and purge cycles, making the facility-specific monitoring plan an important component of demonstrating continuous compliance.
- Cargo-Tank Vapor Tightness Requirements: Based on concerns about the practical limitations of EPA Method 27 testing, EPA is proposing to restore the previous graduated cargo-tank vapor-tightness limits of 1.0 to 2.5 inches of water column. The agency concluded that the more stringent 2024 limits are not reliably achievable nationwide and may approach the precision limitations of the test method, potentially resulting in failed tests even when cargo tanks are effectively vapor-tight. The change could reduce testing failures and compliance burdens for cargo-tank operators.
A Closer Look at Proposed LDAR Changes and Considerations
EPA’s proposed LDAR revisions address both when requirements apply and how facilities would implement them in practice. The changes include a new capital expenditure threshold, revised implementation timelines, requirements for monitoring during gasoline loading, and clarifications related to component monitoring, leak repair, and equipment considered “in gasoline service.”
Proposed Capital Expenditure Threshold
To reduce the likelihood that routine, lower-cost projects trigger NSPS Subpart XXa modification requirements, EPA is proposing a capital expenditure threshold for affected facilities. Under this approach, qualifying projects could proceed without automatically triggering NSPS Subpart XXa and potentially related air permitting obligations. The proposal follows a framework already used in refinery and natural gas processing regulations, and EPA is proposing to adopt the same equation currently used in NSPS Subpart VVb. This change could provide additional flexibility while reducing compliance burdens for routine capital improvement projects.
Proposed 180-Day Implementation Timeline
EPA is proposing to align certain implementation timelines with Subpart XXa by providing 180 days, rather than the original 60 days, for compliance activities. This extended timeline would allow facilities more time to complete a capital expenditure threshold assessment.
EPA notes that existing facilities subject to NESHAP Subparts R or 6B already have up to three years to comply with the referenced NSPS Subpart XXa leak-monitoring requirements. As a result, EPA is not proposing an additional 180 days for completion of the initial instrument-based leak survey. Instead, facilities would be required to complete the first survey by the applicable NESHAP compliance deadline.
Monitoring During Gasoline Loading
Proposed revisions would clarify that instrument-monitoring inspections must occur while gasoline is actively being loaded into a cargo tank, placing monitoring under operating conditions where leaks may be more readily detected.
This requirement could create scheduling and logistical challenges. LDAR inspections are often planned around technician availability, travel efficiency, and facility operating schedules. Coordinating inspections with active loading may be difficult at facilities with infrequent, intermittent, or unpredictable loading activities.
Stakeholders may wish to comment on the operational and technical basis for this requirement, particularly for facilities where loading events occur infrequently or with limited advance notice.
Component-Monitoring Exceptions
NSPS Subpart XXa originally incorporated connector-monitoring exceptions by reference to NSPS Subpart VVa. EPA subsequently removed those provisions from Subpart VVa after determining they had not undergone the appropriate public review process.
In comments on the 2024 rule, the International Liquid Terminals Association (ILTA) requested that EPA remove the resulting outdated references from Subpart XXa. EPA agreed and revised the rule to remove the obsolete cross-references while incorporating the applicable requirements directly into Subpart XXa.
When a Leak Triggers Repair
Recent proposed revisions to NSPS Subpart XXa would clarify how vapor collection system monitoring requirements are applied. Industry stakeholders requested confirmation that a Method 21 reading of 500 ppmv is not itself a violation, but rather the threshold used to identify a leak and initiate repair requirements.
EPA clarified that leaks identified during pre-performance test monitoring must be repaired before a performance test is conducted. The agency also acknowledged that the phrase “no detectable emissions” could be interpreted as establishing a continuous compliance standard, even though it was intended to support a leak identification and repair program. Under the proposal, the 500 ppmv leak definition would serve as the point at which corrective action is required rather than as a standalone violation threshold.
Clarifying Equipment “In Gasoline Service”
EPA is proposing to clarify that backup or secondary control equipment only requires leak monitoring when it contains or comes into contact with gasoline or gasoline vapors. Equipment would not be considered “in gasoline service” simply because it is part of a system that occasionally handles gasoline. EPA is requesting feedback on this proposed clarification.
- Current definition: “A piece of equipment is used in a system that transfers gasoline or gasoline vapors.”
- Proposed definition: “A piece of equipment is used in a system that contains or contacts gasoline or gasoline vapors.”
Although EPA anticipates that the revised definition will not remove any equipment from monitoring requirements, the distinction could create compliance uncertainty in some situations. For example, a line routed to a transmix tank could potentially be monitored at one facility but not another based on differing interpretations of the rule. Industry groups and environmental departments may wish to provide feedback on how EPA can further clarify what constitutes equipment that is “in gasoline service” under the revised definition.
How Would the Proposed LDAR Requirements Affect Bulk Gasoline Plants and Pipeline Pumping Stations?
Of the proposed revisions, the LDAR provisions are among the most operationally significant for bulk gasoline terminals, pipeline pumping stations, and affected facilities. The proposed changes address when requirements apply, how monitoring must be conducted, and how facilities document and respond to emissions leaks.
EPA is proposing to retain annual leak monitoring requirements for bulk gasoline plants and pipeline pumping stations. While commenters raised concerns about monitoring costs, particularly at remote facilities, EPA did not propose changes to the monitoring frequency.
For many facilities, the largest compliance costs may stem from program implementation. Method 21 monitoring generally requires development of a component inventory, equipment tagging, and ongoing recordkeeping. Facilities using the Appendix K OGI monitoring option would face a different set of implementation requirements, including monitoring plans and supporting documentation.
The proposal also highlights several implementation questions that could significantly affect compliance costs. For example, monitoring equipment during cargo tank loading could require additional site visits, coordination, and field time compared to monitoring under normal operating conditions. Additional EPA guidance on these scenarios could help improve consistency and predictability across regulated facilities.
Could EPA Allow Alternatives to Annual Instrument Monitoring?
EPA is requesting comments on possible alternatives to annual instrument monitoring, particularly for facilities with strong monitoring performance and for certain small or remote pipeline pumping stations.
What Is Skip-Period Monitoring?
Skip-period monitoring is a common term for monitoring every two years for facilities with good performance. This option may benefit companies that maintain low leak rates but can create compliance uncertainty and exposure, particularly with turnover among environmental personnel or LDAR contractors.
Instrument Monitoring vs. AVO Inspections
EPA is proposing to retain annual instrument-based leak monitoring for bulk gasoline plants and pipeline pumping stations. The agency cites its 2024 analysis, which estimated annual monitoring would reduce emissions by approximately 60 tpy of HAPs and 600 tpy of VOCs across roughly 1,800 pipeline pumping stations compared to historical monthly audio, visual, and olfactory (AVO) inspections. EPA is requesting comment on whether these requirements should be retained, modified for small or remote facilities, or replaced with alternative monitoring approaches.
How Could EPA Define “Small” or “Remote” Facilities?
In addition to seeking comment on whether alternative monitoring requirements may be appropriate for certain pipeline pumping stations, EPA is requesting comment on how “small” and “remote” facilities could be defined. Specifically, EPA asks whether reduced monitoring requirements should apply to qualifying pipeline pumping stations and seeks input on criteria that could be used to distinguish those facilities. EPA also requests comment on whether distance from the boundary of a metropolitan statistical area could be an appropriate metric for defining a remote facility.
The proposal does not identify a preferred definition for either term. Potential approaches could include the number of pumps, the number of regulated components, installed horsepower, facility throughput, or geographic location. EPA also requests comment on how remote facilities should be identified and how often those determinations should be reevaluated. Potential concepts could include periodic reevaluation on a fixed schedule, such as every two years, or reevaluation tied to operational changes such as increased throughput, facility expansion, or nearby population growth.
What Should Gasoline Distribution Facilities Evaluate Now?
The proposal affects several core compliance programs, including LDAR inspections, performance testing, cargo-tank certification, operating-limit compliance, and recordkeeping. Gasoline distribution facilities should compare the proposed revisions against their site-specific equipment, operations, and compliance programs, particularly in areas where EPA is seeking comment. These include monitoring during gasoline loading, requirements for pipeline pumping stations, definitions of “small” and “remote” facilities, thermal oxidizer operating limits, and cargo-tank vapor-tightness standards. Existing regulatory requirements remain in effect unless and until EPA issues a final rule. Key dates are provided below.
| Date | Proposed Rule Milestone |
| October 5, 2026 | Deadline to request a virtual hearing |
| October 13, 2026 | Virtual hearing, if requested by October 5. |
| October 28, 2026 | Comments on information-collection provisions due to Office of Management and Budget (OMB) |
| November 12, 2026 | Comments on the proposed rule due to EPA |
| May 8, 2027 | First instrument leak survey deadline identified in the draft for existing sources subject to NESHAP Subparts R or 6B |
