As of July 8th, 2024, we’ve expanded upon this Delve to include important information on emission controls at gasoline terminals, including vapor combustion devices, vapor recovery units and flares, and new cargo tank vapor tightness requirements. To jump ahead to that content, click here.

On May 8, 2024, the Environmental Protection Agency (EPA) finalized changes to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Gasoline Distribution Terminals major source category (Subpart R), the NESHAP area source category (Subpart BBBBBB, or 6B), and New Source Performance Standards (NSPS) for Bulk Gasoline Terminals via a new subpart,  Subpart XXa. These changes, effective from July 8, 2024, were originally proposed in 2022, and the final rules are substantially similar to the proposed rules.  

EPA estimates these final rules will apply to nearly 9,500 gasoline distribution facilities. The changes will affect storage tanks, loading operation controls, equipment leak detection, performance testing, and compliance reporting requirements. 

Why is EPA Updating NESHAP and NSPS Regulations?

Under the Clean Air Act (CAA), the EPA is required to periodically assess and revise air toxics standards to help keep regulatory requirements in line with evolving industry practices and technology improvements. This review process is generally referred to as a technology review (TR). EPA’s latest TR of the NESHAP evaluated current practices in emission reduction to assess whether current practices achieve greater emission reductions than existing requirements for facilities in the Gasoline Distribution source category related to storage tanks, loading operations, and equipment leaks. EPA’s TR identified several changes in the approach to emissions reduction, resulting in proposed amendments. At the same time, EPA reviewed NSPS Subpart XX, and determined that the bulk gasoline terminal requirements should also be updated, generally consistent with the TR for the NESHAP regulations.  

For the NESHAP regulations changes, facilities must comply with the new requirements three years after the final rule is published, May 10, 2027. 

Importantly, bulk gasoline terminals that commenced construction, reconstruction, or modification after June 10, 2022 (the proposal date) are subject to the NSPS XXa requirements no later than the rule's effective date (July 8, 2024) or upon startup, whichever is later.  

The following highlights the principle new requirements in modified NESHAP Subparts R and BBBBBB and the new NSPS Subpart XXa. The rules include many details that are not included in this discussion. 

Important Definition Changes in the Amendments for NSPS Subpart XXa, NESHAP Subpart R, and NESHAP BBBBBB

In the recent updates, the EPA defined two different facilities affected by regulations under NSPS Subpart XXa: 

1. Gasoline loading rack (generally consistent with NSPS XX): This includes all loading racks at bulk gasoline terminals that deliver liquid products into gasoline cargo tanks, including the gasoline loading rack, vapor collection systems, and vapor processing system. This affected facility will primarily be subject to the control device provisions. Control device provisions apply primarily to this facility, with the stipulation that flares (defined as a device that uses an open or shrouded flame such that the emission point is not suitable for stack testing) are not acceptable control systems for newly constructed gasoline loading rack facilities; only thermal oxidation or vapor recovery systems are acceptable.

2. Collection of equipment at bulk gasoline terminals: This includes all equipment associated with gasoline loading at the terminal, including lines, pumps, loading racks, vapor collection, and processing systems. This facility primarily falls under equipment leak provisions and covers more piping than NSPS Subpart XX.

In addition to defining new affected facilities, the EPA updated the definition of a bulk gasoline terminal by adding “cargo tank” as one of the gasoline delivery methods to the affected facility. Since “cargo tank” includes both tank trucks and railcars, this closes a prior exception for facilities that received gasoline only by railcar. This provision is immediately effective for NSPS Subpart XXa facilities. For NESHAP Subpart R, the new definition, including cargo tank, becomes effective May 8, 2027 (3 years after the final publication date). The Subpart BBBBBB definition previously included cargo tanks.

Additionally, in the recent update, the EPA clarified components excluded from the calculation of fixed capital costs for reconstruction under Subpart XXa. The EPA excluded the following "frequently replaced components" from the calculation: pump seals, gaskets and swivels for loading arms, gaskets for couplers, couplers and cables for overfill sensors, flexible vapor hoses, and cables and connectors for grounding.

New Equipment Leak Detection Requirements

The following table outlines the new equipment leak detection compliance requirements for the following Subparts: 

• NSPS Subpart XXa: The collection of equipment in gasoline service at a bulk gasoline terminal affected facility.

• NESHAP Subpart R: All equipment in gasoline service at a bulk gasoline terminal or pipeline breakout station

• NESHAP BBBBBB: All equipment in gasoline service at a bulk gasoline terminal, bulk gasoline plant, pipeline breakout station, or pipeline pumping station

• OGI – optical gas imaging
• AVO – audible, visual, olfactory
• DOR – delay of repair

Additional requirements for NESHAP Subpart R and BBBBBB include:

• Maintain a logbook including summary descriptions or diagrams showing the locations of all equipment in gasoline service at the facility.

• The logbook shall be signed by the owner/operator at the completion of each AVO inspection and record information regarding any detected leak and repair resolution.

New Gasoline Storage Vessel Fitting Controls Requirements

The new requirements for fitting controls on gasoline storage vessels vary depending on the facility's classification under NESHAP Subpart R or Subpart BBBBBB.

For NESHAP Subpart R facilities, storage vessels generally need fitting controls in line with NSPS Subpart Kb, with an alternative option for compliance with NESHAP Subpart WW. Detailed cross-references to Subpart Kb can be found in 40 CFR 63.423, particularly in paragraphs (b)(1) for all gasoline storage vessels, (b)(2) for internal floating roof tank vapor space requirements to meet a 25 lower explosive limit (LEL), and (b)(3) for external floating roof tank fitting requirements.

As for NESHAP Subpart BBBBBB facilities, the storage vessel requirements referencing NSPS Subpart Kb are integrated into Table 1 of Subpart BBBBBB.

The applicable compliance dates are as follows:

For NESHAP Subpart R facilities:

• Storage vessels that commenced construction on or before February 8, 1994: compliance with paragraphs (b)(1) and (b)(2) no later than May 8, 2027, and compliance with paragraph (b)(3) May 8, 2034, or the next time the storage vessel is completely emptied and degassed, whichever comes first.

• Storage vessels that commenced construction after February 8, 1994, and on or before June 10, 2022: compliance with paragraphs (b)(1) and (b)(2) no later than May 28, 2027, and compliance with paragraph (b)(3) no later than May 8, 2034, or the next time the vessel is completely emptied and degassed, whichever comes first.

• Storage vessels that commenced construction after June 10, 2022: compliance with all requirements upon startup or July 8, 2024, whichever is later.

For NESHAP BBBBBB facilities:

• Storage vessels that commenced construction or reconstruction on or before June 10, 2022: compliance upon startup, or the next time the storage vessel is completely emptied or degassed, or May 8, 2034, whichever occurs first.

• Storage vessels that commenced construction or reconstruction after June 10, 2022: compliance upon startup or July 8, 2024, whichever is later.

Internal Floating Roof LEL Leak Monitoring Requirements

NESHAP Subparts R and BBBBBB facilities that commenced construction on or before June 10, 2022, must commence internal floating roof gasoline storage vessel LEL monitoring by May 8, 2027, or upon startup, whichever is later. Affected facilities that commenced construction or reconstruction after June 10, 2022, must comply with these requirements upon startup or July 8, 2024, whichever is later.  

The affected internal floating roof storage vessels require LEL monitoring once every 12 months. Although the first monitoring event will not be required until 2027, EPA expects that facilities will use the 3 years to make any necessary upgrades to meet the new standard. An LEL reading above 25 percent on a 5-minute rolling average for a 20-minute test period constitutes an inspection failure. LEL meters must be calibrated per the manufacturer’s recommendations, and calibrations must be conducted with the extension tube in place. The vapor measurement must be taken no more than 3 feet above the stationary internal floating roof deck. At the time of the measurement, wind speeds at the top of the tank should be 5 miles per hour (mph) or less to the extent practicable and shall not exceed the annual average wind speed at the site or 15 mph, whichever is less. The data collection requirements are detailed, including taking readings at least every 15 seconds, LEL instrument gasoline vapor correction factors, instrument documentation, documentation if the LEL monitoring event occurred at a time other than concurrent with the annual visual inspection, and more.  LEL remonitoring is required to confirm that a repair was successful. 

What Should I Be Doing Now to Ensure Compliance?

1. Determine whether your gasoline bulk terminal may be subject to NSPS Subpart XXa.

• Since NSPS regulatory applicability begins on the proposal publication date, NSPS Subpart XXa applies to facilities constructed, reconstructed, or modified (CRM) after June 10, 2022. Hence, facilities that were CRM between June 10, 2022, and July 8, 2024, must comply with NSPS Subpart XXa as of July 8, 2024, and upon startup.  

• Trihydro recommends that you review all changes to your bulk gasoline terminal considering this compliance timeframe. In particular, ensure consideration of the new “collection of all equipment at a bulk gasoline terminal associated with gasoline loading” affected source, as gasoline piping changes remote from the loading operations may also trigger NSPS Subpart XXa requirements. 

2. Verify the “commenced construction” date for all gasoline storage vessels at NESHAP Subparts R and BBBBBB facilities and whether those gasoline storage vessels meet the applicable requirements in 40 CFR 63.423(b) (cross-referencing NSPS Subpart Kb). If upgrades are necessary, ensure that these upgrades are accounted for in future storage vessel inspection and repair schedules.

3. Conduct pre-compliance OGI or Method 21 inspections of gasoline piping at NESHAP Subparts R or BBBBBB gasoline distribution facilities, including bulk gasoline terminals, pipeline breakout stations, and pipeline pumping stations. A pre-compliance inspection will allow the facility to evaluate leaks and make repairs prior to the May 10, 2027, compliance date.

4. Conduct pre-compliance LEL monitoring of internal floating roof tanks using a methodology consistent with the new monitoring requirements. Note that through-the-hatch LEL monitoring is not consistent with the new requirements, which require that the LEL reading be taken within 3 feet of a stationary floating roof deck.

5. Update the NESHAP Subpart R or BBBBBB gasoline piping AVO inspection workbook to address all affected gasoline service piping. 

6. Establish recordkeeping systems to track OGI (or Method 21) inspections of gasoline piping and LEL inspections of internal floating roof storage tanks. Trihydro would be happy to discuss potential data solutions with you.  

Control Device Requirements in New NSPS Subpart XXa

Gasoline loading racks that commence construction, reconstruction, or modification after June 10, 2022 (the proposal date) are subject to the NSPS XXa requirements no later than the rule's effective date (July 8, 2024) or upon startup, whichever is later.  

The regulation includes many details that cannot be summarized here. If your facility is or becomes subject to NSPS XXa, Trihydro recommends a more detailed review of your compliance options based on your intended control device technology.

For a newly constructed gasoline loading facility (i.e., newly constructed after June 10, 2022), the following control requirements apply:

• Facilities using thermal oxidation controls must meet a limit of 1.0 milligrams (mg) of total organic compounds (TOC) per liter (L) of liquids loaded into a gasoline cargo tank.  

• Facilities using vapor recovery system controls must meet a limit of 550 parts per million by volume (ppmv) TOC (which EPA has deemed equivalent to 1.0 mg/L) on a 3-hour rolling average basis.  

For modified or reconstructed gasoline loading facilities (i.e., modified or reconstructed after June 10, 2022):

• Facilities using thermal oxidation controls must meet a limit of 10 mg/L of liquids loaded into a gasoline cargo tank of TOC. 

• Facilities using vapor recovery system controls must meet a limit of 5,500 ppmv TOC (which EPA has deemed equivalent to 10.0 mg/L) on a 3-hour rolling average basis.  

• If a flare is used, EPA requires provisions to ensure good combustion efficiency. Flare monitoring alternatives are available and broadly reference the refinery flare monitoring requirements at 40 CFR 63.670, although there are provisions for one-time flare tip velocity and net heating value determinations, as well as other exceptions. The regulatory requirements for this alternative are very detailed and are not summarized here.  

Additional details:

• A flare is a thermal combustion device with an open or shrouded flame that does not emit pollutants through a conveyance suitable for conducting a performance test. 

• If no gasoline cargo tanks are being loaded, those periods may be excluded from the 3-hour rolling average.  A gasoline cargo tank is a delivery tank truck or railcar that is loading or loaded gasoline on the immediately previous load. If the prior content is unknown, the operator must assume it contains gasoline and is, therefore, a gasoline cargo tank.  

• The TOC measurement can exclude methane if it is measured using EPA-approved test methods.

• All loading into gasoline cargo tanks must use submerged fill tubes.

• If using a thermal oxidation control system, the relevant operating limit is applicable at all times when liquid product is loaded into gasoline cargo tanks.  Conversely, you must exclude those periods when there is no liquid product being loaded from the 3-hour rolling average.  The thermal oxidation system must also demonstrate continuous compliance with a temperature limit equal to the lowest 3-hour average temperature resulting from a compliant performance test. 

• If using a vapor recovery system, the relevant operating limit applies at all times that the vapor recovery system is operating, including during regeneration of the carbon bed.

• The 3-hour rolling average is determined based on the arithmetic mean of the 36 prior 5-minute periods of valid operating data collected as specified for the applicable monitoring parameter.  

Control Device Requirements in NESHAP Subpart R 

NESHAP Subpart R applies to major source gasoline distribution facilities (including bulk gasoline terminals (gasoline throughput greater than 20,000 gallons/day design capacity or as limited by enforceable permit limit) and pipeline breakout facilities). Facilities that are currently subject to Subpart R must comply with the new requirements by May 8, 2027, three years after the final rule publication date.  

Many of the Subpart R provisions refer to NSPS Subpart XXa, therefore carrying forward provisions such as the exclusion of methane from TOC determination and how the 3-hour rolling average is determined.  

• Facilities equipped with thermal oxidation systems (including flares) must meet a limit of 10 mg/L TOC.  The thermal oxidation system must also demonstrate continuous compliance with a temperature limit equal to the lowest 3-hour average temperature resulting from a compliant performance test. 

• Facilities equipped with a flare (as opposed to a thermal oxidizer) require provisions to ensure good combustion efficiency. Flare monitoring alternatives are available and broadly reference (through NSPS XXa) refinery flare monitoring requirements in 40 CFR 63.670, although there are provisions for one-time flare tip velocity and net heating value determinations. The regulatory requirements for this alternative are very detailed and are not summarized here. 

• Facilities equipped with a VRU must meet a limit of 5,500 ppmv TOC 3-hour rolling average.

Control Device Requirements in NESHAP Subpart BBBBBB

NESHAP Subpart BBBBBB applies to area source gasoline distribution facilities.  Facilities that are currently subject to Subpart BBBBBB must comply with the new requirements by May 8, 2027, three years after the final rule publication date.  

Similar to Subpart R, many Subpart BBBBBB provisions refer to NSPS Subpart XXa, so provisions such as the exclusion of methane from TOC determination and how the 3-hour rolling average is determined are carried forward.  

• Large bulk terminals (total gasoline throughput of 250,000 gallons/day or greater, actual annual average) equipped with thermal oxidation systems (including flares) must meet a limit of 35 mg/L TOC (versus 80 mg/L in the prior version). The thermal oxidation system must also demonstrate continuous compliance with a temperature limit equal to the lowest 3-hour average temperature resulting from a compliant performance test. 

• Large bulk terminals equipped with a flare (as opposed to a thermal oxidizer) require provisions to ensure good combustion efficiency. Flare monitoring alternatives are available and broadly reference (though NSPS XXa) to refinery flare monitoring requirements in 40 CFR 63.670, although there are provisions for one-time flare tip velocity and net heating value determinations. The regulatory requirements for this alternative are very detailed and are not summarized here.  

• Large bulk terminals equipped with a VRU must meet a limit of 19,200 ppmv TOC 3-hour rolling average.

• Bulk terminals with an actual (not designed) gasoline throughput of 4,000 gallons/day on an annual average basis (the equivalent of 1,460,000 gallons/year) or greater require vapor balancing for the loading of storage vessels and cargo tanks.  

• Pressure relief valves (i.e., conservation vents) on fixed roof tanks used in vapor balancing must have opening pressures not less than 18 inches of water (0.65 psig) or at a vacuum of less than 6 inches of water (0.22 psig).

• Small bulk terminals (gasoline throughput between 20,000 and 250,000 gallons/day) and bulk gasoline plants (gasoline throughput less than 20,000 gallons/day) loading racks must use submerged fill (as is currently required).

Cargo Tank Vapor Tightness Requirements

Cargo tank testing requirements, the method used to verify that cargo tanks are vapor-tight, have been modified.  This testing is typically conducted following EPA Method 27 and is typically conducted on behalf of the cargo tank owner, not the gasoline distribution facility. The test results are provided to the gasoline distribution facility, which tracks those results in the terminal management system and cargo tank operator login to verify that only vapor-tight tanks are loaded at the facility.  

• A new graduated vapor tightness testing requirement is uniformly applicable to NSPS Subpart XXa and NESHAP Subparts R and BBBBBB, ranging from 0.50 to 1.25 inches of water pressure drop over a 5-minute period, depending on the cargo tank compartment size (see NSPS Subpart XXa, Table 1 to paragraph (f)(1)). For comparison, the current Subpart R requirement has a graduated range from 1.0 to 2.5 inches of water, and Subpart BBBBBB and XX require 3 inches of water.  

• All cargo tanks loaded must be certified to the new limit by May 10, 2027 (3 years after the final rule publication date).

Questions?

Trihydro has assisted facilities with regulatory compliance since 1984. Our regulatory specialists are available to help facilities in the gasoline distribution source category understand how the new requirements impact your projects and operations. We also have dedicated software (LeakTracker ProTM) to support these monitoring requirements. Contact us if we can be of assistance!