Proposed Revisions to the NESHAP for Marine Tank Vessel Loading Operations (MTVLO)

Author: Eric Swisher

The U.S. Environmental Protection Agency (U.S. EPA) has conducted its required periodic technology review and proposes to amend the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Marine Tank Vessel Loading Operations (MTVLO) codified at 40 CFR Part 63, Subpart Y. The proposed revisions to the MTVLO NESHAP were published in the Federal Register at 91 FR 10559 on March 4, 2026. Comments must be submitted to the docket (Docket ID No. EPA–HQ– OAR–2025–0207) on or before April 20, 2026. Companies with MTVLO should consider commenting. U.S. EPA is soliciting comments on 31 specific items concerning developments in practices, processes, and control technologies that reduce emissions of hazardous air pollutants (HAP) from MTVLO. The wide range of topics requested for comment by U.S. EPA provides opportunities for input on proposed revisions to the MTVLO NESHAP. The topics on which U.S. EPA is requesting comments include:

• Submittal of any additional information, including control device developments, that could enhance U.S. EPA’s technology review;
• Applicability and exemptions;
• Overlap provisions for facilities subject to other emissions standards;
• Proposed compliance dates for implementation of the revisions;
• Leak detection, monitoring, and work practices;
• Removal of startup, shutdown, malfunction (SSM), affirmative defense, and maintenance allowances;
• Ongoing performance testing, flare monitoring, and sampling methods;
• Operating and emissions limits;
• Editorial/technical clarifications; and
• Electronic reporting requirements.

U.S. EPA last finalized changes to the rule in 2011 when it completed its risk and technology review. For this technology review, U.S. EPA has proposed a determination that there are no new technologies for emissions control relevant to the source category and that any improvements in required control efficiency would not be cost effective. For example:

• U.S. EPA proposes not to require loading emissions controls for MTVLO sources below the major source threshold due to cost;
• U.S. EPA proposes to retain the <1.5 pounds per square inch absolute (psia) vapor pressure exemption due to cost (instead of determining that it is a regulatory gap that must be filled); and
• U.S. EPA determined that adding leak detection and repair (LDAR) requirements for liquid components or reducing the leak definition or frequency of monitoring for the existing LDAR requirements is not necessary due to cost and that minimal HAP emissions reductions that would be achieved. They do, however, propose some clarifications to the LDAR requirements.

Also of particular interest in the proposed revisions to the MTVLO NESHAP are updates to the maintenance allowance provisions, ongoing performance testing requirements, and flare monitoring requirements. Specifically, U.S. EPA is proposing:

• Removal of the maintenance allowance provisions, which exempted certain maintenance activities from being treated as deviations or violations and allowed extra time beyond standard repair deadlines for equipment taken out of service for maintenance or repair.
• Updated performance testing requirements, which would add a requirement to perform ongoing performance testing for non-flare, combustion type control devices every 60 calendar months, and changes to how operating parameter limits are set.
• Additional electronic reporting requirements.
• Enhanced monitoring for MTVLO that vent to flares based on the requirements of 40 CFR Part 63, Subpart CC – Petroleum Refineries NESHAP. This change would require monitoring of the flare vent/supplemental gas and steam/air assist volumetric flow rates, heating value of the vent gas, flame presence, and visible emissions.

U.S. EPA proposes that compliance with the additional electronic reporting requirements be achieved within 180 days of the final rule, compliance with the flare monitoring changes be achieved within three years of the final rule, and compliance with all other new requirements be achieved on the effective date of the final rule.

Comments should consider both the preamble discussion of the technology review and U.S. EPA’s “Redline of 40 CFR Part 63, Subpart Y, Showing Proposed Amendments” posted in the docket. The redline version of the rule was provided by U.S. EPA as a “convenience” but it also presents the manner in which the proposed revisions discussed in the preamble would be incorporated into a final rule. For example, the Federal Register notice discusses the addition of annual relative accuracy test audits (RATAs) for control devices that use Continuous Emissions Monitoring Systems (CEMS) for compliance. However, the redline version of the rule incorporates the requirement to complete a RATA by requiring the CEMS to meet 40 CFR Part 60, Appendix F – Procedure 1 [Appendix F (P1)]. Appendix F (P1) does include the requirement of a RATA, but it also includes quarterly Cylinder Gas Audits (CGA) and even competing definitions with 40 CFR Part 63, Subpart A – General Provisions for periods when the CEMS are deemed out-of-control.

Comments on proposed rules do not always have to focus on “the bad” or on items you oppose or wish to clarify. If there are parts of the existing rule or proposed revisions you consider as “the good” (changes or parts of the analysis you agree with), comments should be submitted in support of the proposed requirements or changes that were considered but not proposed to ensure U.S. EPA considers the true impact of potential changes. For example, if the cost of implementing a change would be even higher than U.S. EPA estimated, that information should be provided. If compliance with the flare monitoring requirements will take three years to achieve, a compliance timeline could be developed and submitted to support that timing.

Providing U.S. EPA with effective comments on proposed rule revisions is both an “art” and a “science.” Comments should be developed based on input from various stakeholders within a company or industry. The MTVLO NESHAP impacts work tasks for loading operations and logistics, instrumentation, maintenance, environmental, and potential subcontractors used as part of LDAR programs. Each stakeholder has a valuable perspective and their input should be considered when developing comments. Comments provided to U.S. EPA on the proposed MTVLO NESHAP revisions may:

• Affect the outcome of the final regulation,
• Provide additional technical or economic information,
• Support existing requirements or proposed revisions, and/or
• Seek clarification on how proposed changes would be implemented.

ALL4 has extensive experience evaluating proposed regulatory actions, determining impacts of proposed changes, and preparing technical comments that impact final outcomes. We implemented enhanced flare monitoring programs for many facilities and can help you evaluate gaps in your program. For more information on the MTVLO NESHAP, or assistance in evaluating the impact of the proposed revisions and preparing comments for submittal to U.S. EPA, please contact Eric Swisher at eswisher@all4inc.com.