SUPPLEMENTARY INFORMATION:

Throughout this document whenever “we,” “us,” or “our” is used, we mean the EPA.

I. What is EPA proposing to approve?

The EPA is proposing to approve a revision to Indiana's VOC SIP for Keystone. The company has requested that it be permitted to use an oil cover as an equivalent control device for its cold cleaner degreaser, as provided in 326 IAC 8-1-5 and 326 IAC 8-3-2. The oil cover, Aquastrip Fume Seal, is a layer of mineral oil at least one-inch thick floating over the cleaning solvent in a dip tank. The solvent is a mixture of two water miscible compounds, n-Methyl Pyrrolidone (NMP) and monoethanolamine (MEA). The oil cover controls VOC emissions from the dip tank by reducing solvent evaporation.

II. What are the changes from the current rule?

Indiana's cold cleaner degreaser control requirements are contained in 326 IAC 8-3-2. Under 326 IAC 8-3-2(b)(1), degreasers with solvent that is heated to a temperature of greater than forty-eight and nine-tenths (48.9) degrees Celsius, or 120 degrees Fahrenheit, are required to control VOC emissions using one of the following control devices: a freeboard ratio of 0.75 or greater; a water cover over the solvent when the solvent used is insoluble in, and heavier than, water; a refrigerated chiller; carbon adsorption; or VOC emission control equipment operated in accordance with 326 IAC 8-3-8(b)(3). Per 326 IAC 8-1-5(a), “[a]n owner or operator of a source may submit a petition . . . requesting a site-specific Reasonably Available Control Technology (RACT) plan as an alternative to the requirements in 326 IAC 8.” In accordance with 326 IAC 8-1-5(a)(6), the petition must include, among other things, a demonstration that the alternative control program constitutes RACT for the petitioned facility, and address the factors listed in 326 IAC 8-1-5(a)(6). Such alternative systems, however, must be submitted to and approved by the EPA as a SIP revision as required by 326 IAC 8-1-5(c).

III. What is the EPA's analysis of the supporting materials?

IDEM supplied the EPA with technical information on the solvents used by Keystone and the requested oil cover. IDEM also provided information on why a water cover would not work with the solvents used and why the freeboard ratio of the tank cannot practically be increased to the level required by 326 IAC 8-3-2.

The solvents Keystone uses, NMP and MEA, are miscible in water, and attempts to use a water cover would fail to reduce VOC emissions. The water would blend with the cleaning solvents and not provide any barrier against solvent evaporation. To meet the freeboard ratio requirement of 0.75, Keystone would need to raise the freeboard height on its dip tank to 108 inches (9 feet). This would require that the building be altered to accommodate the dip tank's increased height. The cost of raising the roof or lowering the floor makes this option cost prohibitive. IDEM also addressed why the use of a refrigerated condenser and carbon adsorption system, listed as options in 326 IAC 8-3-2(b), would not be feasible for Keystone due to the capital expenditures required for the installation, operation, and modification to the building, as well as increased worker hazards and environmental impacts from either control system.

In its ”Guide to Cleaner Technologies: Cleaning and Degreasing Process Changes” (EPA/625/R-93/017), the EPA suggests the use of an oil cover for operations using heated NMP. Keystone will use a heated NMP and MEA solvent blend in its operation. The supplied technical information shows that NMP and MEA have similar vapor densities. The oil cover, a layer of mineral oil at least one inch thick, provides a physical barrier between the cleaning solvents and the atmosphere. Thus, it is reasonable to expect an oil cover will provide an equivalent control technique for VOC emissions from an NMP and MEA solvent blend.

This request constitutes a petition for a site-specific RACT plan under 326 IAC 8-1-5. Consequently, Keystone was required to demonstrate to IDEM that the oil cover constitutes RACT for the subject facility, as well as address the other factors specified in 326 IAC 8-1-5(a).

IDEM provided a demonstration of compliance with Clean Air Act (CAA) section 110(l), 42 U.S.C. 7410(l), which prohibits SIP revisions from interfering with attaining air quality standards and reasonable further progress requirements. IDEM's 110(l) demonstration describes how the oil cover layer will remain on top of the degreasing solvent and control emissions of VOCs by reducing solvent evaporation, which also reduces the heat required for operations as it acts similar to an insulator. The oil cover is expected to provide equivalent control of VOC emissions compared to the use of controls required by 326 IAC 8-3-2 and therefore has no adverse impact on air quality. The EPA concurs with the 110(l) demonstration that this action will not interfere with air quality standards and reasonable further progress requirements.

IV. What action is the EPA taking?

The EPA is proposing to approve revisions to VOC emissions regulations for the Keystone aluminum alloy wheel refurbishing and distribution facility in Huntington County, Indiana. More specifically, the EPA proposes to approve Commissioner's Order 2025-Air-01 into the Indiana SIP. The revision provides for the use of an oil cover as an equivalent VOC emission control system under 326 IAC 8-1-5 and 326 IAC 8-3-2 for its cold cleaner degreaser.

V. Incorporation by Reference

In this rulemaking, EPA is proposing to include in a final EPA rule regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, the EPA is proposing to incorporate by reference Indiana Commissioner's Order 2025-Air-01, signed February 19, 2025, discussed in section IV of this preamble. The EPA has made, and will continue to make, these documents generally available through www.regulations.gov and at the EPA Region 5 Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).

VI. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). ( printed page 9800) Thus, in reviewing SIP submissions, the EPA's role is to approve State choices, provided that they meet the criteria of the CAA. Accordingly, this action merely approves State law as meeting Federal requirements and does not impose additional requirements beyond those imposed by State law. For that reason, this action:

• Is not a significant regulatory action subject to review by the Office of Management and Budget underExecutive Order 12866 (58 FR 51735, October 4, 1993);
• Is not subject toExecutive Order 14192 (90 FR 9065, February 6, 2025) because SIP actions are exempt from review under Executive Order 12866;
• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.);
• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);
• Does not have federalism implications as specified inExecutive Order 13132 (64 FR 43255, August 10, 1999);
• Is not subject toExecutive Order 13045 (62 FR 19885, April 23, 1997) because it approves a State program;
• Is not a significant regulatory action subject toExecutive Order 13211 (66 FR 28355, May 22, 2001); and
• Is not subject to requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA.

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where the EPA or an Indian Tribe has demonstrated that a Tribe has jurisdiction. In those areas of Indian country, the rulemaking does not have Tribal implications and will not impose substantial direct costs on Tribal governments or preempt Tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).