As air quality consultants to the fuels industry, we’re hearing regularly from gasoline distribution and storage operators who are working to address the U.S. Environmental Protection Agency’s (EPA’s) 2024 updates to federal air-quality regulations. These changes—collectively referred to as the Gasoline Distribution Rules (GDR)—revise existing requirements and introduce an additional New Source Performance Standard (NSPS). The EPA also introduced NSPS Subpart Kc, applicable to volatile organic liquid storage vessels, which impacts the gasoline distribution industry and anyone who stores volatile organic liquids.
For operators of bulk gasoline terminals, bulk plants, and pipeline breakout stations, the rulemaking represents one of the most consequential regulatory shifts in years.
For operators of bulk gasoline terminals, bulk plants, and pipeline breakout stations, the rulemaking represents one of the most consequential regulatory shifts in years. With a key compliance deadline approaching in May 2027, operators are grappling with how the new requirements affect capital projects, routine maintenance, monitoring programs, and long-term planning.
Barr has been deeply engaged in helping gasoline distribution operators make applicability determinations and develop practical, defensible compliance strategies. We’ve gained some important insights from early implementation efforts that can help others navigate these rules with more confidence.
A quick refresher on the regulatory changes
The EPA finalized the GDR on May 8, 2024. The updated rules include:
- 40 CFR 63 Subpart BBBBBB (GACT 6B)—Revised requirements for area-source gasoline distribution facilities
- 40 CFR 63 Subpart R (MACT R)—Revised requirements for major-source gasoline-distribution facilities
- 40 CFR 60 Subpart XXa (NSPS XXa)—A new NSPS applicable to bulk gasoline terminals that commence construction, modification, or reconstruction after June 10, 2022
Although many of the revised GACT and MACT requirements do not take effect until May 8, 2027, NSPS XXa is already in effect. As a result, new projects can trigger new compliance obligations if they meet the regulatory definition of a modification or reconstruction.
Later, on October 15, 2024, EPA promulgated NSPS 40 CFR Part 60 Subpart Kc, which sets emission control, monitoring, and recordkeeping requirements for storage tanks that contain volatile organic liquids—including gasoline. While separate, NSPS Kc requirements often overlap with those of the GDR, meaning gasoline distribution operators must often address these 2024 updates in tandem.
Structured screening tools help clarify NSPS applicability
The first and most common challenge operators face is determining whether a planned project triggers the requirements of NSPS XXa.
The first and most common challenge operators face is determining whether a planned project triggers the requirements of NSPS XXa. Projects that might seem routine—loading rack upgrades, vapor piping reroutes, and adding piping runs with new pumps, valves, and connectors for reliability—now have operators asking: Is this a “modification” or “reconstruction” under NSPS rules?
Without a clear framework for answering this question, operators risk unknowingly triggering NSPS requirements and failing to comply. Standard internal guidance and screening tools for determining NSPS applicability can help make these decisions more quickly—and consistently—while reducing uncertainty and the risk of costly surprises.
Alongside the applicability determinations we’re supporting for operators planning individual projects, we’re preparing guidance documents to help them evaluate future modification and reconstruction scenarios under the GDR. These include decision frameworks and other tools that streamline GDR applicability determinations and improve their consistency across multiple facilities. Equipped with internal guidance, project owners are identifying potential compliance obligations early and making informed decisions about project scope, schedule, and cost.
Lower explosive limit (LEL) monitoring: A case study in the importance of aligning monitoring instrumentation, procedures, and recordkeeping
The updated gasoline distribution rules place increased emphasis on monitoring, testing, and documentation. The new lower explosive limit (LEL) monitoring requirements are a great example. Certain internal floating roof storage tanks subject to the GDR (GACT 6B and MACT R) and/or NSPS Kc require annual LEL monitoring as part of routine tank inspections.
Many operators are conducting LEL monitoring with the same portable four-gas meters they use for personal safety monitoring. These instruments can be effective for compliance monitoring if paired with appropriate procedural controls. While helping operators adapt their four-gas meters and data-collection protocols to GDR and NSPS requirements, we’ve seen challenges with calibration gas availability, achieving tight span-check tolerances, and limitations of the catalytic bead sensors commonly used in these meters. If these challenges aren’t accounted for in monitoring procedures, they can lead to inaccurate data.
Clear documentation of calibration practices, monitoring steps, data logging, and data reduction in the form of standard operating procedures helps to produce repeatable, defensible LEL monitoring results—regardless of equipment choice.
Clear documentation of calibration practices, monitoring steps, data logging, and data reduction in the form of standard operating procedures helps to produce repeatable, defensible LEL monitoring results—regardless of equipment choice. We help operators develop standard, GDR-compliant instrumentation plans, monitoring procedures, and templates tailored to their equipment, and we field-test them for workability. Clear, thorough, and tested procedures are the foundations of successful monitoring programs—especially those spanning multiple facilities—helping staff perform consistently and report accurately.
With procedures in hand, it’s time to consider how best to manage the monitoring data. LEL monitoring events can generate large datasets, and operators need practical approaches for storing, validating, and retrieving records. We’ve helped operators build entirely new data-management workflows and adapt existing workflows for compliance. For example, operators who choose to leverage their four-gas meters and existing data-management systems may need to adjust their procedures to account for certain factors, such as the amount of data a four-gas meter can store. When it comes to monitoring, standard, instrument-aligned procedures benefit the entire process—from instrument deployment to report submission.
Planning for 2027—and beyond
With the May 2027 compliance deadline for revised GACT 6B requirements approaching, many operators are using this window to assess existing systems, identify data gaps, and prioritize compliance projects. It’s a good idea—early evaluations can help align compliance efforts with planned maintenance outages, tank inspections, or capital improvements, reducing overall disruption.
Wherever you are in navigating the GDR or NSPS Kc, Barr can help—from applicability determinations and project evaluations to monitoring-program design and field-implementation support. By combining regulatory insight with hands-on operational experience, we can help translate regulatory text to workable, real-world compliance solutions. Contact our team to get started.
Heading to the B.L.E.W.S. Symposium next month?
Join us at the B.L.E.W.S. Symposium, April 8–9 in Dallas, Texas, where we’ll be diving deep into the most pressing regulatory topics in gasoline distribution. Visit us at Booth #8 or attend one of our technical sessions listed below.
- In the Weeds with Gasoline Distribution Rules: Tony Shoberg, vice president and senior chemical engineer, and Matt Turner, senior environmental scientist, will present and discuss implementation challenges associated with GACT 6B and NSPS XXa, including modification triggers, affected facility definitions, flare requirements, and monitoring-system design.
- Practical LEL Monitoring Lessons Learned for Tanks Subject to NSPS Kc and the Gasoline Distribution Rules: Al Reich, senior chemical engineer, will share his real-world lessons from implementing LEL monitoring programs across multiple facilities, with a focus on instrumentation, calibration, procedures, and data management.
Both sessions are grounded in our field experience and designed to help attendees better understand how the regulations translate into day-to-day compliance.
About the authors
Tony Shoberg, vice president and senior chemical engineer, has helped fuel-sector clients comply with air-quality regulations for 20 years. He has been instrumental in growing Barr’s environmental-compliance practice in Duluth, Minnesota, with a strong emphasis on air permitting and compliance for petroleum pipeline terminals, refineries, and other fuels infrastructure. Tony’s work with fuels clients includes environmental audits and due diligence reviews, stationary-source evaluations, compliance management planning, and environmental permitting applicability and strategy.
Al Reich, senior chemical engineer, has nearly 15 years of experience supporting the petroleum transportation and refining industry. He provides air-quality compliance and permitting services with a particular focus on storage vessel regulations and emissions calculations. His work generally involves helping clients navigate regulatory interpretations, compliance demonstrations, program implementation, permitting, and audits. He manages the Barr Tank Emission Calculation Spreadsheet (BTECS), a Microsoft Excel-based tool designed to calculate emissions from storage tanks.
Related projects
Environmental permitting and compliance support at terminals
Barr provides ongoing environmental compliance support for five terminals associated with the Superior refinery in Minnesota and Wisconsin. We develop, maintain, and update comprehensive compliance action plans that help terminal staff understand regulatory requirements, define responsibilities, and manage compliance across air, water, waste, storage tanks, spill prevention, remediation, clean fuels, and the Emergency Planning and Community Right-to-Know Act (EPCRA). These plans are reinforced through regular updates and annual training with terminal staff to support consistent, effective compliance.
Air-quality permitting and compliance support at pipeline terminals
Barr assisted TransCanada (now TC Energy) with various air-quality permitting and compliance projects, including air-emission inventories, developing air-quality inspection forms, reviewing inspection procedures, updating compliance plans, reviewing regulatory applicability determinations, calculating potential emissions, emissions-tracking support, preparing a Part 70 operating permit application, and providing day-to-day regulatory interpretations. Our support resulted in an improved air-compliance program equipped with tools and procedures for compliance management.
Permitting and environmental review for pipeline terminal expansion
Magellan Midstream Partners decided to expand its refined petroleum terminal near Rochester, Minnesota. The expansion triggered environmental review by the Minnesota Pollution Control Agency (MPCA). Magellan turned to Barr to prepare an Environmental Assessment Worksheet and permit applications to support the project.
