On September 24, 2026, EPA signed a proposed reconsideration of its 2024 gasoline distribution rules (91 FR 61175), after granting reconsideration in February 2025. The proposal addresses NESHAP Subparts R and BBBBBB and NSPS Subpart XXa, covering equipment applicability, leak detection, control-device monitoring, and cargo-tank vapor tightness. EPA is not proposing to change the numerical loading emission limits or extend the compliance deadlines established in the 2024 rule. For regulated facilities, the significance lies in compliance demonstrations. These proposed revisions warrant review alongside each facility’s equipment configuration, loading practices, and compliance schedule. Comments on EPA’s proposed revisions are due by November 12, 2026. EPA is not reopening other aspects of the 2024 rule and does not intend to respond to comments on provisions the proposal does not address.
Collection of Equipment NSPS Applicability
EPA proposes a capital expenditure threshold for process improvements to the “collection of equipment” affected facility under the redline of Subpart XXa. Qualifying projects costing no more than 8 percent of equipment replacement cost, adjusted by the specified Consumer Price Index ratio, would not automatically trigger modification under this provision. The proposed process improvement definition includes routine changes for safety, maintenance, energy savings, bottleneck removal, and environmental control.
This provision specifically concerns the “collection of equipment” affected facility and uses the replacement cost of its depreciable components. It would not establish a blanket exemption for every terminal project or replace separate loading rack applicability evaluations for the “total of all racks” affected facility.
Leak Detection and Repair – LDAR
EPA proposes several changes and clarifications to leak detection and repair requirements:
- Initial surveys: Facilities directly subject to Subpart XXa equipment-leak requirements would conduct their first instrument survey within 180 calendar days of becoming subject. Facilities subject through a NESHAP cross-reference would conduct that survey by the NESHAP compliance date, without an additional 180 days. For existing sources subject to Subparts R and BBBBBB, that deadline remains May 8, 2027. EPA has not proposed an extension.
- Operating conditions: Instrument surveys would expressly occur during active gasoline loading into a gasoline cargo tank. EPA’s intent is to ensure the monitoring takes place during active vapor collection and processing.
- Connector exceptions: Subpart XXa would directly state monitoring exceptions previously incorporated through Subpart VVa, with clarifications covering pumps and valves.
- Pretest screening: EPA clarifies that detecting a leak at the 500 ppmv threshold would trigger repair obligations rather than automatically establish a violation. All identified pretest leaks would require repair before the performance test; delay-of-repair provisions would not apply.
- Backup systems: A revised “in gasoline service” definition would address equipment that contains or contacts gasoline or gasoline vapors. Backup systems would receive audio, visual, or olfactory scrutiny during use and instrument monitoring if operating during a scheduled survey. Temporary use would not itself require an additional instrument survey.
EPA proposes to retain annual instrument monitoring for bulk gasoline plants and pipeline pumping stations. EPA requests comments on possible pumping-station alternatives, including performance-based skip periods and provisions for small or remote facilities.
Prior Cargo Tank Loads
EPA proposes to retain the assumption that a cargo tank with unknown previous contents is a gasoline cargo tank, rejecting petitioner requests to assume the prior load equals the current load. Thus, as the rule stands, loading a non-gasoline product would not, by itself, establish that gasoline cargo tank requirements are inapplicable.
Proposed recordkeeping changes would simplify requirements for facilities that treat all loading operations as involving gasoline cargo tanks, remove duplicative records, and clarify 15-minute recordkeeping periods for the flare-monitoring alternative. Five-minute loading records would remain relevant where minimum gasoline loading rates or gasoline-to-total-liquid loading ratios are used.
Facilities should examine the information supporting any exclusion of non-gasoline loading periods from operating-limit calculations. Connecting the vapor collection system and deciding which periods enter a monitoring calculation are related but distinct compliance questions.
Two Options for Thermal Oxidation System Temperature Monitoring
EPA is co-proposing and seeking comments on two approaches for thermal oxidation systems, including vapor combustion units.
Option 1 – Revised Performance Testing and Temperature Calculations
Option 1 would remove the minimum gasoline test volume and reduce the minimum test duration from six to three hours. Testing would represent normal operations and include at least 36 qualifying five-minute intervals involving gasoline loading or other liquid loading into cargo tanks known to have contained gasoline on their immediately previous load. The operating limit would be the lowest three-hour rolling average temperature established during a compliant test. This approach would apply to sources subject to the 1, 10, and 35 mg/L emission limits.
Three elapsed hours would not necessarily produce thirty-six qualifying intervals. Loading and temperature records would need sufficient detail to identify these intervals. Mixed-product testing also requires planning because the emission standard remains total organic compounds per liter of gasoline loaded; non-gasoline throughput does not increase this denominator.
Assist-gas demand would depend partly on which periods enter the temperature calculation. Excluding cooler non-gasoline-only periods that do not meet the qualifying criteria could produce a higher operating limit than a calculation that includes those periods. During subsequent operations, non-gasoline loading into cargo tanks with unknown previous contents would still count toward temperature compliance. Facilities with these loading patterns could therefore need additional assist gas to maintain the resulting three-hour average.
Option 2 – Fixed 400°F Mid-Stack Temperature Limit
Option 2 would establish a minimum mid-stack temperature of 400°F for every applicable five-minute period during active product loading into gasoline cargo tanks at sources subject to the 10 or 35 mg/L limits. Facilities would still demonstrate compliance with the applicable emission limit through performance testing. New sources subject to the 1 mg/L limit would continue using a test-derived combustion-zone temperature limit, calculated from the lowest three-hour rolling average using the qualifying five-minute periods described above.
Stack height and existing thermocouple placement would affect implementation. EPA proposes measuring mid-stack temperature at least 19 feet above the top of the burners or, where the stack extends less than 22 feet above the burners, 3 feet below the stack top. The 19-foot and 22-foot measurements are referenced to the burner tops, not ground level. Therefore, existing temperature sensors may not meet the proposed location requirement, potentially requiring relocation or an additional sensor. The 400°F figure should be evaluated alongside the measurement location and five-minute compliance periods.
Net Heating Value and Assist Air
EPA proposes to retain the net heating value dilution parameter, NHVdil, for air-assisted devices using the flare-monitoring provisions. For thermal oxidation systems with multiple burners, EPA would revise the diameter term used in the calculation to reflect the distance across the burner arrangement. The 22 Btu/ft² limit would remain.
EPA also proposes maximum assist-air rates for air-assisted thermal oxidation systems and flares. Thermal oxidizers would establish the maximum from performance testing; flares would establish it through tuning to the minimum rate needed for smokeless operation at high gasoline loading. Blower settings and damper positions would require inspection each operating day, with associated records and exceedance reporting.
For the minimum net heating value demonstration, EPA would retain 14 grab samples but allow collection at intervals of at least 20 minutes, shortening the current 14-day sampling period.
Vapor Recovery Monitoring
Vapor recovery unit (VRU) concentration limits are proposed to return from a three-hour rolling average back to a six-hour rolling average, comprising of 72 five-minute operating periods. EPA intends to retain the requirement to meet the emission limit at all times, including periods of carbon-bed regeneration and purging, even when product loading has stopped. Records would expressly identify each five-minute operating period.
Additionally, regarding the continuous emission monitoring system (CEMS) downtime provisions, EPA is proposing to allow facilities to submit a site-specific limited alternative monitoring plan submitted through EPA’s Compliance and Emissions Data Reporting Interface (CEDRI), which would replace the existing previous-ten-cycle assessment. The proposal would allow purge cycle duration to be determined from valve sequencing and timing, with records of the plan and each period of use. The 240-hour annual limit on alternative-plan use would remain.
Facilities evaluating these revisions should consider both their averaging calculations and their ability to implement the downtime plan promptly.
Updates to Cargo Tank Vapor-Tightness Requirements
EPA proposes to replace the 2024 graduated cargo-tank pressure and vacuum change limits of 0.5-1.25 inches of water column with limits of 1.0-2.5 inches, depending on compartment size. EPA cites Method 27 precision and temperature-related variability as reasons for revisiting the requirements.
Annual vapor-tightness certification would remain. In essence, the proposal plans to use the former Subpart R thresholds, rather than restore the 3.0-inch criterion historically used under Subpart XX and Subpart BBBBBB.
Other revisions would clarify ppmv units, correct the Subpart BBBBBB vapor-tightness cross-reference, and require deviation reports to provide operating values only for the parameters that deviated.
Compliance Planning Continues
Based on the current reconsideration language published, EPA has not proposed to extend the existing compliance dates. Existing sources subject to Subparts R and BBBBBB would still need to implement an LDAR program by May 8, 2027. EPA should expect to receive comments requesting an extension to these dates given the extensive timeline for EPA’s reconsideration.
Facilities should use the reconsideration to review project applicability, test plans, prior-load information, monitoring calculations, and operating procedures. Facility-specific review can identify which proposed changes offer useful flexibility and which require additional preparation.
EPA’s gasoline distribution rulemaking page provides rulemaking materials. Trinity Consultants can assist with evaluating the implications for your facility and developing an appropriate compliance approach.
