2024-22171. Designation of Areas for Air Quality Planning Purposes; Redesignation Request and Associated Maintenance Plan for Whatcom County, WA 2010 SO2 Nonattainment Area

Table 1—Whatcom County (Partial) Monitored SO ₂ Concentrations

[ppb]

Station	2021 99th Percentile	2022 99th Percentile	2023 99th Percentile	2021-2023 Design value
Ferndale-Mountain View Road	2.6	3.3	4.4	3
Ferndale-Kickerville Road	2.4	3.1	4.4	3

As shown, the 3-year design values for 2021-2023 at the monitoring stations are well below the 2010 1-hour SO₂ NAAQS. Concentrations of SO₂ at these monitoring stations decreased significantly from the 2017-2019 design value of 106 ppb following the shutdown of the Intalco facility. Since the facility last operated in July 2020, 99th percentile values at the monitoring stations have not exceeded 4.4 ppb SO₂ . These low values are anticipated to be consistent, as the state demonstrated in its analysis that SO₂ emissions since 2020 have consistently decreased to levels well below the 2010 1-hour SO₂ NAAQS during both curtailment and permanent closure of the Intalco facility.^[6]

As part of Washington's 2022 attainment plan and 2024 redesignation request, Ecology submitted information to support a showing that the Ferndale-Mountain View Road monitor was sited in the area of maximum ambient SO₂ concentration within the Whatcom County (partial) SO₂ NAA in accordance with the 2014 SO₂ NAA Guidance. Ecology identified appropriate locations for the two Ferndale monitors in 2015 by running the AERMOD ^[7] dispersion model using SO₂ actual emissions from Intalco.^[8] The EPA reviewed Washington's information regarding this showing in designating the area nonattainment in Round 4. We found that the state's modeling assessment was reliable for determining the extent of the area of violation of the 1-hour SO₂ NAAQS. Specifically, we agreed that the region of violation was most likely due to plume downwash at the Intalco facility during certain wind conditions, that the modeled area of violation does not extend far from the Intalco facility fenceline, that the gradient of concentration near the areas of violation is steep, quickly dropping with distance from the Intalco facility fenceline, and that other nearby industrial facilities do not sufficiently contribute to violations of the SO₂ NAAQS to warrant inclusion in the nonattainment area boundary.^[9] With Intalco permanently closed, monitored SO₂ concentrations in the Whatcom County (partial) SO₂ nonattainment area are well below the 75 ppb standard.

In this action, the EPA is proposing to determine that the Whatcom County (partial) SO₂ nonattainment area is attaining the 2010 1-hour SO₂ NAAQS, and therefore meets the requirements of CAA section 107(d)(3)(E)(i). If the 3-year design value exceeds the NAAQS prior to the EPA taking action in response to the state's request, the EPA will not take final action to approve the redesignation request.^[10]

Because the EPA's analysis in determining whether an area has attained under the clean data policy is the same as its analysis under the first redesignation criterion, the EPA is also here proposing that the Whatcom County (partial) SO₂ nonattainment area qualifies for a determination of attainment under the clean data policy, based on the 2021-2023 monitoring data at the two Ferndale monitoring stations. The clean data policy represents the EPA's interpretation that certain requirements of part D of title I of the Act are suspended for areas that are currently attaining the NAAQS. The requirements that are suspended in an area attaining the standard include the requirements to submit an “attainment SIP” that provides for: attainment of the NAAQS; implementation of all reasonably available control measures (RACM); reasonable further progress (RFP); and implementation of contingency measures for failure to meet deadlines for RFP and attainment. In the 2014 SO₂ NAA Guidance, the EPA explained our intention to apply the EPA's clean data policy to the 2010 SO₂ primary NAAQS.^[11]

In the event that the EPA does not finalize the proposed redesignation, the EPA may choose to finalize the clean data determination, thereby suspending attainment planning-related requirements for the area for as long as the area continues to attain the standard.

Criteria (2)—Washington Has a Fully Approved SIP Under Section 110(k) and Criteria (5)—Washington Has Met All Applicable Requirements Under Section 110 and Part D of Title I of the CAA

For redesignating a nonattainment area to attainment under a NAAQS, the CAA requires the EPA to determine that the state has met all applicable requirements for that NAAQS under section 110 and part D of title I of the CAA (CAA section 107(d)(3)(E)(v)) and that the state has a fully approved SIP under section 110(k) for that NAAQS for the area (CAA section 107(d)(3)(E)(ii)). The EPA proposes to find that Washington has met all applicable SIP requirements for the Whatcom County (partial) SO₂ nonattainment area for the 2010 SO₂ NAAQS under section 110 of the CAA (general SIP requirements) for purposes of redesignation. Additionally, the EPA proposes to find that the Washington SIP satisfies the criterion that it meets applicable SIP requirements for purposes of redesignation under part D of title I of the CAA in accordance with section 107(d)(3)(E)(v). Further, the EPA proposes to determine that the SIP is fully approved with respect to all requirements applicable for the 2010 SO₂ NAAQS for purposes of redesignation in accordance with section 107(d)(3)(E)(ii). In making the determinations, the EPA ascertained ( print page 79198) which requirements are applicable to the Whatcom County (partial) SO₂ nonattainment area and, if applicable, that they are fully approved under section 110(k).

a. The Whatcom County (Partial) SO₂ Nonattainment Area Has Met All Applicable Requirements Under Section 110 and Part D of the CAA

General SIP Requirements. General SIP elements and requirements are delineated in section 110(a)(2) of title I, part A of the CAA. These requirements include, but are not limited to, the following: submittal of a SIP that has been adopted by the state after reasonable public notice and hearing; provisions for establishment and operation of appropriate procedures needed to monitor ambient air quality; implementation of a source permit program; provisions for the implementation of part C requirements (Prevention of Significant Deterioration (PSD)) and provisions for the implementation of part D requirements (New Source Review (NSR) permit programs); provisions for air pollution modeling; and provisions for public and local agency participation in planning and emission control rule development.

Section 110(a)(2)(D) requires that SIPs contain certain measures to prevent sources in a state from significantly contributing to air quality problems in another state. To implement this provision, the EPA has required certain states to establish programs to address the interstate transport of air pollutants. The section 110(a)(2)(D) requirements for a state are not linked with a particular nonattainment area's designation and classification in that state. The EPA believes that the requirements linked with a particular nonattainment area's designation and classifications are the relevant measures to evaluate in reviewing a redesignation request. The transport SIP submittal requirements, where applicable, continue to apply to a state regardless of the designation of any one particular area in the state. Thus, the EPA does not believe that the CAA's interstate transport requirements should be construed to be applicable requirements for purposes of redesignation.

In addition, the EPA believes other section 110 elements that are neither connected with nonattainment plan submissions nor linked with an area's attainment status are applicable requirements for purposes of redesignation. The area will still be subject to these requirements after the area is redesignated. The section 110 and part D requirements which are linked with a particular area's designation and classification are the relevant measures to evaluate in reviewing a redesignation request. This approach is consistent with the EPA's existing policy on applicability ( i.e., for redesignations) of conformity and oxygenated fuels requirements, as well as with section 184 ozone transport requirements. See Reading, Pennsylvania, proposed and final rules (61 FR 53174-53176, October 10, 1996), (62 FR 24826, May 7, 2008); Cleveland-Akron-Loraine, Ohio, final rule (61 FR 20458, May 7,1996); and Tampa, Florida, final rule (60 FR 62748, December 7, 1995). See also the discussion on this issue in the Cincinnati, Ohio, redesignation (65 FR 37890, June 19, 2000), and in the Pittsburgh, Pennsylvania, redesignation (66 FR 0399, October 19, 2001).

Title I, Part D, Applicable SIP Requirements. Section 172(c) of the CAA sets forth the basic requirements of attainment plans for NAAs that are required to be submitted pursuant to section 172(b). Subpart 5 of part D, which includes section 191 and 192 of the CAA, establishes requirements for SO_2, nitrogen dioxide and lead NAAs. A thorough discussion of the requirements contained in sections 172(c) can be found in the General Preamble for Implementation of Title I (57 FR 13498, April 16, 1992).

Section 172(c)(1) requires the plans for all NAAs to provide for the implementation of all RACM as expeditiously as practicable and to provide for attainment of the NAAQS. The EPA interprets this requirement to impose a duty on all nonattainment areas to consider all available control measures and to adopt and implement such measures as are reasonably available for implementation in each area as components of the area's attainment demonstration. Under section 172, states with nonattainment areas must submit plans providing for timely attainment and meeting a variety of other requirements.

The EPA's longstanding interpretation of the nonattainment planning requirements of section 172 is that once an area is attaining the NAAQS, those requirements are not “applicable” for purposes of CAA sections 107(d)(3)(E)(ii) and (v) and therefore, need not be approved into the SIP before the EPA can redesignate the area. In the 1992 General Preamble for Implementation of Title I, the EPA set forth its interpretation of applicable requirements for purposes of evaluating redesignation requests when an area is attaining a standard. See57 FR 13498, 13564 (April 16, 1992). The EPA noted that the requirements for RFP and other measures designed to provide for attainment do not apply in evaluating redesignation requests because those nonattainment planning requirements “have no meaning” for an area that has already attained the standard. Id. This interpretation was also reiterated in the 1992 Calcagni Memo and consistently applied in many proposed and final redesignation actions since. The EPA's understanding of section 172 also forms the basis of its Clean Data Policy, which was articulated with regard to SO₂ in the 2014 SO₂ NAA Guidance and suspends a state's obligation to submit most of the attainment planning requirements that would otherwise apply, including an attainment demonstration and planning SIPs to provide for RFP, RACM, and contingency measures under section 172(c)(9). Courts have upheld the EPA's interpretation of section 172(c)(1) for “reasonably available” control measures and control technology as meaning only those controls that advance attainment, which precludes the need to require additional measures where an area is already attaining. NRDC v. EPA, 571 F.3d 1245, 1252 (D.C. Cir. 2009); Sierra Club v. EPA, 294 F.3d 155, 162 (D.C. Cir. 2002); Sierra Club v. EPA, 314 F.3d 735, 744 (5th Cir. 2002); Sierra Club v. EPA, 375 F.3d 537 (7th Cir. 2004). But see Sierra Club v. EPA, 793 F.3d 656 (6th Cir. 2015).

Therefore, because the design values for 2021-2023 are well below the NAAQS in the Whatcom County (partial) SO₂ NAA, no additional measures are needed to provide for attainment, and section 172(c)(1) requirements for an attainment demonstration and RACM are not part of the “applicable implementation plan” required to have been approved prior to redesignation per CAA section 107(d)(3)(E)(ii). The other section 172 requirements that are designed to help an area achieve attainment—the section 172(c)(2) requirement that nonattainment plans contain provisions promoting reasonable further progress, the requirement to submit the section 172(c)(9) contingency measures that would apply if the area fails to timely attain, and the section 172(c)(6) requirement for the SIP to contain control measures necessary to provide for attainment of the NAAQS—are also not required to be approved as part of the “applicable implementation plan” for purposes of satisfying CAA section 107(d)(3)(E)(ii).

Section 172(c)(3) requires submission and approval of a comprehensive, accurate, and current inventory of actual emissions. The requirement for an emission inventory can be satisfied by ( print page 79199) meeting the inventory requirements of the maintenance plan.^[12] Ecology submitted an emissions inventory as part of the maintenance plan for the Whatcom County (partial) SO₂ nonattainment area, and this inventory will be discussed further in the maintenance plan portion of this proposed action.

Section 172(c)(4) requires the identification and quantification of allowable emissions for major new and modified stationary sources to be allowed in an area, and section 172(c)(5) requires source permits for the construction and operation of new and modified major stationary sources anywhere in the nonattainment area. The EPA has determined that, since PSD requirements will apply after redesignation, areas being redesignated need not comply with the requirement that a NSR program be approved prior to redesignation, provided that the area demonstrates maintenance of the NAAQS without part D NSR. A more detailed rationale for this view is described in a memorandum from Mary Nichols, Assistant Administrator for Air and Radiation, dated October 14, 1994, entitled “Part D New Source Review Requirements for Areas Requesting Redesignation to Attainment.” Ecology has demonstrated that the Whatcom County (partial) SO₂ nonattainment area will be able to maintain the NAAQS without part D NSR in effect, and therefore Washington need not have fully approved part D NSR programs prior to approval of the redesignation request. Nevertheless, we note that Washington's nonattainment NSR for major sources was last approved by the EPA on October 6, 2016 (81 FR 69386) and the NWCAA's nonattainment NSR for minor sources was last approved by the EPA on June 5, 2020 (85 FR 36156). Both programs meet all relevant NSR requirements for SO₂ . Washington's PSD program for major sources will become effective in the Whatcom County (partial) SO₂ nonattainment area upon redesignation to attainment. Section 172(c)(7) requires the SIP to meet the applicable provisions of section 110(a)(2). As noted above, the EPA believes the Washington SIP meets the requirements of section 110(a)(2) applicable for purposes of redesignation.

Section 176 Conformity Requirements. Section 176(c) of the CAA requires states to establish criteria and procedures to ensure that federally supported or funded projects conform to the air quality planning goals in the applicable SIP. The requirement to determine conformity applies to transportation plans, programs, and projects that are developed, funded, or approved under title 23 of the United States Code (U.S.C.) and the Federal Transit Act (transportation conformity) as well as to all other federally supported or funded projects (general conformity). State transportation conformity SIP revisions must be consistent with Federal conformity regulations relating to consultation, enforcement, and enforceability that the EPA promulgated pursuant to its authority under the CAA.

The EPA interprets the conformity SIP requirements as not applying for purposes of evaluating a redesignation request under section 107(d) because, like other requirements listed above, state conformity rules are still required after redesignation and Federal conformity rules apply where state rules have not been approved. See Wall v. EPA, 265 F.3d 426 (6th Cir. 2001) (upholding this interpretation); see also60 FR 62748 (December 7, 1995) (redesignation of Tampa, Florida).

For these reasons, the EPA proposes to find that Washington has satisfied all applicable requirements for purposes of redesignation of the Whatcom County (partial) SO₂ nonattainment area under section 110 and part D of title I of the CAA.

b. The Whatcom County (Partial) SO₂ Nonattainment Area Has a Fully Approved Applicable SIP Under Section 110(k) of the CAA

The EPA has fully approved the applicable Washington SIP for the Whatcom County (partial) area under section 110(k) of the CAA for all requirements applicable for purposes of redesignation. As indicated above, the EPA believes that the section 110 elements that are neither connected with nonattainment plan submissions nor linked to an area's nonattainment status are not applicable requirements for purposes of redesignation. The EPA has approved all part D requirements applicable under the 2010 SO₂ NAAQS, as identified above, for purposes of this redesignation.

Criteria (3)—The Air Quality Improvement in the Whatcom County (Partial) SO₂ Nonattainment Area Is Due to Permanent and Enforceable Reductions in Emissions

For redesignating a nonattainment area to attainment, the CAA requires the EPA to determine that the air quality improvement in the area is due to permanent and enforceable reductions in emissions resulting from implementation of the SIP, applicable Federal air pollution control regulations, and other permanent and enforceable reductions (CAA section 107(d)(3)(E)(iii)). The EPA proposes to find that Washington has demonstrated that the observed air quality improvement in the Whatcom County (partial) SO₂ NAA is due to permanent and enforceable reductions in emissions. Specifically, the EPA considers the shutdown of the Intalco facility, identified as the key contributor to the SO₂ NAAQS violations at the Ferndale-Mountain View Road monitor,^[13] to be both permanent and enforceable. Given the well-established correlation of much lower SO₂ emissions at the two Ferndale monitors during periods when Intalco has not operated and the very low SO₂ concentrations following the facility's permanent shutdown, the EPA anticipates that the area will continue to attain the SO₂ NAAQS. As stated in the Calcagni Memo, “Emission reductions from source shutdowns can be considered permanent and enforceable to the extent that those shutdowns have been reflected in the SIP and all applicable permits have been modified accordingly.” ^[14] Ecology revoked Alcoa's Title V (operating) and NSR permits for the Intalco facility.^[15] The facility is now permanently closed, making its future operation impossible and thus displaying the permanence of the emissions reductions in the NAA. Any new sources that may come into being within the area would be required to demonstrate that their new SO₂ emissions would not interfere with attainment and maintenance of the 2010 1-hour primary SO₂ NAAQS. Therefore, the EPA is proposing to find that the air quality improvement in the Whatcom County (partial) SO₂ NAA is due to permanent and enforceable reductions in emissions.

Criteria (4)—The Whatcom County (Partial) SO₂ Nonattainment Area Has a Fully Approved Maintenance Plan Pursuant to Section 175A of the CAA

To redesignate a NAA to attainment, the CAA requires the EPA to determine that the area has a fully approved maintenance plan pursuant to section 175A of the CAA (CAA section 107(d)(3)(E)(iv)). In conjunction with its ( print page 79200) request to redesignate the Whatcom County (partial) SO₂ nonattainment area to attainment for the 2010 1-hour SO₂ NAAQS, Ecology submitted a SIP revision to provide for the maintenance of the 2010 1-hour SO₂ NAAQS for at least 10 years after the effective date of redesignation to attainment. The EPA is proposing to find that this maintenance plan for the area meets the requirements for approval under section 175A of the CAA.

a. What is required in a maintenance plan?

CAA section 175A sets forth the elements of a maintenance plan for areas seeking redesignation from nonattainment to attainment. Under section 175A, the plan must demonstrate continued attainment of the applicable NAAQS for at least 10 years after the Administrator approves a redesignation to attainment. Eight years after the redesignation, the state must submit a revised maintenance plan demonstrating that attainment will continue to be maintained for the 10 years following the initial 10-year period. To address the possibility of future NAAQS violations, the maintenance plan must contain contingency measures as the EPA deems necessary to assure prompt correction of any future 2010 1-hour SO₂ violations. The Calcagni Memo provides further guidance on the content of a maintenance plan, explaining that a maintenance plan should address five elements: The attainment emissions inventory, maintenance demonstration, monitoring, verification of continued attainment, and a contingency plan. As is discussed more fully below, the EPA is proposing to determine that Washington's maintenance plan includes all the necessary components and is thus proposing to approve it as a revision to the Washington SIP.

b. Attainment Emissions Inventory

As part of a state's maintenance plan for a 2010 SO₂ NAA, the air agency should develop an attainment inventory to identify the level of emissions in the affected area which is sufficient to attain and maintain the SO₂ NAAQS.^[16] Washington selected 2020 as the base year ( i.e., attainment emissions inventory year) for developing an emissions inventory for SO₂ in the NAA through 2033. The 2020 base year represents the most contemporaneous National Emissions Inventory (NEI) available. The 2020 base year also represents Intalco's final year of operation with facility emissions of 1,613 tons of SO_2.

In the 2019-2021 monitoring period, representative of the base year, the Ferndale-Mountain View Road monitor had a 3-year design value of 56 ppb and the Ferndale-Kickerville Road monitor had a 3-year design value of 44 ppb, both below the 75 ppb concentration of the 1-hour SO₂ NAAQS. The 2020 99th percentiles recorded at the two monitors are consistent with these low design values at 62.0 ppb and 59.2 ppb, respectively. The EPA has therefore determined that this is a level sufficient to attain the 2010 1-hour SO₂ NAAQS and is proposing to find that the attainment inventory submitted as part of Washington's maintenance plan meets the “Attainment Emissions Inventory” requirement.

The EPA notes that the permanent shutdown of Intalco has left the Whatcom County (partial) SO₂ NAA with no significant sources of SO₂, and the maintenance plan for the area contains an emissions inventory which projects no significant SO₂ emissions in the NAA from 2020 through 2033. The EPA therefore does not anticipate emissions activity in the 2010 SO₂ nonattainment area that will approach 1,613 tons of SO₂.

Table 2—Base Year 2020 and Projection Years 2026 and 2033 SO ₂ Emissions for the Maintenance Area

[Tons per year]

Source	2020 Base year	2026 Projection	2033 Projection
Alcoa Primary Metals Intalco Works	1613.4000	0	0
Residential non-wood fuel use	0.0026	0.0026	0.0026
Residential wood combustion (home heating)	0.0266	0.0266	0.0266
On-road mobile sources	0.0095	0.0095	0.0095
Ships (commercial marine vessels)	0.0221	0.0221	0.0221
Railroad (locomotives)	0.0002	0.0002	0.0002
Non-road mobile equipment and vehicles (NEC)	0.0010	0.0010	0.0010
Total	1,613.4620	0.0620	0.0620