Cleveland Attains Ozone — and Four Source-Side Obligations Didn't Change

On May 14, 2026, EPA published a final Clean Data Determination (CDD) for the seven-county Cleveland, Ohio area under the 2015 8-hour ozone NAAQS of 70 ppb. The agency’s news release reads the way agency news releases always read: “EPA proposes to redesignate Cleveland area to attainment for ozone — area now meets national air”. If you are a multi-state environmental manager with a plant in Cuyahoga, Geauga, Lake, Lorain, Medina, Portage, or Summit County, the safety manager forwarded that headline to you within an hour. By lunch, somebody on the operations side was already asking whether the permit constraints could come off and whether a pending capex project could be repriced on minor-source assumptions.

Hold the answer. The May 14 action is a Clean Data Determination under 40 CFR 51.1118. It suspends Ohio EPA’s obligation to submit certain attainment-related planning SIPs. It does not redesignate the area to attainment, it does not lift the Serious nonattainment classification, and it does not change a single source-side compliance obligation inside the seven-county boundary. Four obligations in particular continue exactly as they did on May 13: RACT, NNSR at Serious-area thresholds, transportation and general conformity, and anti-backsliding under CAA §§ 110(l) and 193. This post is what an environmental manager forwards to operations leadership before anyone makes a permit-strategy call on the Cleveland facility.

⚡ TL;DR: A Clean Data Determination is a planning-paperwork suspension, not a regulatory unlock. Cleveland’s seven-county area remains classified Serious nonattainment for the 2015 ozone NAAQS. RACT limits, NNSR offset thresholds, conformity, and anti-backsliding all continue. Redesignation is a separate action, still pending.

What the May 14, 2026 EPA Action Actually Says

The headline rule appears in the Federal Register at 91 FR 27211 — published May 14, 2026 — as a final action approving Ohio’s request for a Clean Data Determination for the 2015 ozone NAAQS for the Cleveland area. The legal mechanism is 40 CFR 51.1118, titled “Suspension of SIP planning requirements in nonattainment areas that have air quality data that meet an ozone NAAQS.” The rule implements EPA’s long-standing Clean Data Policy (EPA — Redesignation and Clean Data Policy (CDP)).

The trigger for a CDD is monitoring data. EPA looks at the most recent three years of quality-assured ozone monitoring data and computes the design value — the three-year average of the annual fourth-highest daily maximum 8-hour ozone concentration. If that design value is at or below 70 ppb, the area’s monitoring data meet the standard, and the planning-SIP submission obligations tied to attainment of that standard are suspended for as long as the data continue to meet it. The Cleveland CDD relies on the 2023–2025 design value period, which clears the 70 ppb threshold after EPA’s January 12, 2026 concurrence on Ohio EPA’s exceptional events demonstration excluding three days of June 2023 ozone exceedances driven by Canadian wildfire smoke transport (91 FR 9800 — Cleveland CDD proposed action).

What the CDD does, on the state-administrative side, is real. Ohio EPA is no longer required to submit the Serious-area attainment demonstration, RACM analysis, RFP demonstration, contingency measures, and other planning SIP elements specifically tied to attaining the 2015 standard for Cleveland. That suspension lifts automatically if a future three-year design value violates the standard. Until then, Ohio EPA’s planning workload on the Cleveland 2015 ozone packages drops.

What the CDD does not do is the rest of this post.

CDD Is Not Redesignation — and Cleveland Is Still Classified Serious

This is the central technical distinction, and it is the one most likely to get misread in a meeting. A Clean Data Determination is not a redesignation to attainment. They are different actions under different statutory provisions, and they produce different consequences.

A CDD under 40 CFR 51.1118 suspends planning SIP submission obligations. That is its entire effect. It does not change the area’s designation. It does not change the area’s classification. It does not relieve any source of any obligation tied to the area’s nonattainment status.

A redesignation to attainment is a separate action under CAA section 107(d)(3)(E). It requires EPA to find that the area has attained the standard, that EPA has fully approved the applicable SIP, that improvement in air quality is due to permanent and enforceable emission reductions, that the state has met all applicable requirements under section 110 and Part D of the Act, and that the state has submitted a fully approvable section 175A maintenance plan demonstrating continued attainment for at least 10 years (with a follow-on plan due 8 years after redesignation extending the demonstration another 10 years).

For Cleveland, the redesignation request and the section 175A maintenance plan were proposed for approval on April 10, 2026 (91 FR 18355 — Cleveland redesignation proposal). EPA has not yet finalized that action. Until it does, Cleveland remains designated nonattainment and classified Serious by operation of law — the area was bumped from Marginal to Moderate on October 7, 2022 and from Moderate to Serious on December 17, 2024 after missing two successive attainment dates.

The practical consequence is straightforward. Every NSR threshold, every RACT obligation, every conformity demonstration, and every anti-backsliding constraint that applied to a Cleveland-area source on May 13, 2026 still applies on May 15, 2026. The CDD changes Ohio EPA’s paperwork. It does not change yours.

⚠️ What’s at stake: Reading the May 14 CDD as a redesignation is a permit-strategy error. A source manager who approves a major-modification project on minor-source assumptions inside the Cleveland Serious-area boundary is exposed to the same NNSR enforcement regime that applied before the CDD — without the legal cover of an issued NNSR permit.

The Four Source-Side Obligations That Did Not Change

1. RACT Continues — Every Federally Approved Emission Limit Stays Enforceable

Reasonably Available Control Technology requirements adopted to address ozone nonattainment are emission control programs, not planning SIPs. They are not suspended by a CDD. The RACT limits already in the Ohio SIP — including the source-specific non-CTG RACT submittals approved as part of the Cleveland Serious-area package on February 27, 2026 — remain enforceable as written (EPA — RACT Requirements in Ozone Nonattainment Areas).

If your facility holds an emission limit in your Title V permit that traces back to an Ohio SIP RACT rule for VOC or NOx, that limit continues. Compliance demonstration, recordkeeping, and reporting continue. The CDD does not provide a basis for amending or terminating any RACT-derived permit condition.

2. NNSR Continues at Serious-Area Thresholds and Offset Ratios

For any new major source or major modification inside the seven-county area, Nonattainment New Source Review continues to apply at the Serious-area thresholds. A new major source is a source with potential-to-emit of 50 tons per year or more of either VOC or NOx. A major modification at an existing major source is an aggregated five-year increase of 25 tons per year or more of either pollutant. Offsets apply at the Serious-area ratio (EPA — Required SIP Elements by Nonattainment Classification; EPA — Nonattainment NSR Basic Information).

The CDD does not move Cleveland into the easier Marginal or Moderate tier where the major-source threshold sits at 100 tpy. The 50/25 thresholds and the Serious-area offset ratio remain in effect until EPA finalizes a redesignation and approves the maintenance plan. If a Cleveland-area capex project was scoped against Serious-area NNSR last week, it gets scoped against Serious-area NNSR this week.

3. Transportation and General Conformity Continue

Federally funded or approved transportation projects and federal actions in the Cleveland area must continue to demonstrate conformity with the SIP for the 2015 ozone NAAQS. The CDD does not lift the conformity obligation. MPOs preparing transportation conformity determinations continue to model against the SIP budgets that apply to the area.

For source-side managers, this matters when a federal permit, a federal funding decision, or a federal project approval is in your project’s critical path — a USACE Section 404 wetlands permit on a site expansion, for example, or a federal grant component on a co-located infrastructure project. General conformity has not gone away.

4. Anti-Backsliding Continues — State-Side Rule Rollbacks Still Fail § 110(l) and § 193

CAA § 110(l) prohibits EPA from approving a SIP revision that would interfere with attainment, reasonable further progress, or any other applicable requirement. CAA § 193 provides parallel protection against the removal or relaxation of nonattainment-area control measures unless equivalent protection is maintained.

Anti-backsliding is the rule that prevents a state from reading “Cleveland is attainment now” as authority to roll back any nonattainment-area control measure tied to the 2015 ozone standard. Until the redesignation is final and a section 175A maintenance plan is approved and the maintenance plan establishes the long-term control framework, those existing control measures stay in place. A Cleveland-area source negotiating for a state-side relaxation of an existing rule will run into anti-backsliding before it gets to a SIP revision package.

Who This Affects in the iSi Service Region

Ohio is not in iSi’s primary service region — we operate across 40 states with concentration in Kansas, Oklahoma, Texas, Missouri, Nebraska, Colorado, and Arkansas. The Cleveland CDD matters to iSi clients in two specific ways.

First, multi-state operators with a Cleveland-area plant in addition to Midwest or Plains operations need a clear read on what the May 14 action does and does not do. If a corporate environmental team is preparing a multi-site permit-strategy memo this quarter, the Cleveland facility goes in the “still Serious” column, not the “attainment” column. Capital projects sequenced against Serious-area NNSR continue to be sequenced against Serious-area NNSR.

Second, the Cleveland action is a useful template for several iSi-territory urban areas still in nonattainment for the 2015 ozone NAAQS — including the Dallas-Fort Worth and Houston areas in Texas and the Denver Metro / North Front Range area in Colorado. The same CDD mechanism under 40 CFR 51.1118 is available to those areas if and when their design values clear. The Cleveland action shows what to expect when it happens — and the limits of what it changes. CDD does not equal redesignation in Texas any more than it does in Ohio. The source-side obligations under the state-administered NSR programs (TCEQ in Texas, CDPHE-AQCC in Colorado, DEQ in Oklahoma) continue at the classification thresholds in force, regardless of whether the state’s planning SIP submission obligations are suspended.

The federal classification thresholds and offset ratios are uniform under federal law. The state implementing rules and forms differ. Confirm state-specific guidance before acting on any nonattainment-related project in any iSi-territory state.

💰 The cost of non-compliance: NNSR violations under Clean Air Act § 113 can carry civil penalties of more than $100,000 per day per violation under the inflation-adjusted statutory schedule. A single mis-aggregated major modification at an existing major source — netting errors, project-grouping errors, offset shortfalls — has historically driven Region 5 consent decrees combining seven-figure penalties with mandatory supplemental environmental projects. The CDD does not change the federal NNSR program operating inside the seven-county Cleveland area. A source manager who misreads the May 14 headline and signs off on a project under minor-source assumptions inherits the full pre-CDD penalty exposure.

What Changes for Ohio EPA — and Why That Doesn’t Help Your Permit

The change worth naming on the state-administrative side: Ohio EPA’s obligation to submit the Serious-area attainment demonstration, the RACM analysis, the RFP demonstration, contingency measures, and other planning SIP elements tied to attaining the 2015 ozone standard for Cleveland is suspended. This is a meaningful workload reduction for Ohio EPA’s planning staff. It is meaningful for Ohio EPA’s federal SIP submission calendar.

It does not flow through to your permit. The Ohio SIP rules already in place — RACT limits, NSR thresholds, monitoring and recordkeeping requirements, source-specific permit terms — remain federally enforceable. Ohio EPA’s permit writers are not unbinding any condition on the basis of the CDD. Region 5 enforcement priorities for Ohio nonattainment areas have not been re-scoped on the basis of the CDD.

If a Cleveland-area facility manager hears “Ohio EPA’s planning SIPs are suspended” and reads it as “our facility’s compliance posture loosened,” that is a misread. The facility’s Title V permit, NNSR construction permits, RACT limits, and conformity-linked obligations remain exactly as they were on May 13.

What to Do This Quarter

For multi-state operators with a Cleveland-area facility, three actions belong on the second-quarter calendar before any permit-strategy assumption gets made:

Pull the current Title V permit and any active NNSR construction permits for the Cleveland facility. Confirm which conditions reference the area’s nonattainment status, which trace back to Ohio SIP RACT rules, and which were established under Serious-area NNSR netting. None of those should change on the basis of the CDD. Document the no-change conclusion in the file before anyone in operations asks.
Reconfirm the NNSR applicability analysis on any Cleveland-area capex project currently in scoping or design. Major-source threshold remains 50 tpy VOC or NOx. Major-modification threshold remains 25 tpy aggregated over five years. Offset ratio remains the Serious-area ratio. If a project was sized against Serious-area NNSR last quarter, it stays sized that way now.
Track the redesignation rulemaking and the section 175A maintenance plan separately. The April 10, 2026 proposed redesignation is the document that, when finalized along with an approved maintenance plan, will adjust long-term obligations. The CDD is not that document. Keep the proposed redesignation and the eventual final action in the regulatory tracker as a distinct line item.

For prospective new sources or major modifications weighing a Cleveland-area capital project in the next 12 to 18 months, the same point applies in the inverse: do not price the project on an attainment-area NSR assumption, and do not assume offset costs will drop. Until EPA finalizes the redesignation and approves the maintenance plan, the project gets scoped under Serious-area NNSR.

When This Comes Up in Other iSi-Territory Areas

If you operate facilities across the iSi service region and one of them sits inside a 2015 ozone NAAQS nonattainment area — Houston-Galveston-Brazoria, Dallas-Fort Worth, the Denver Metro / North Front Range area — keep this distinction in your back pocket. When a CDD is proposed for any of those areas in the next two to three years, the same four obligations will continue under the state-administered SIPs. The corporate environmental team that already understands the CDD-versus-redesignation distinction from the Cleveland precedent will not have to relearn it on the next one.

The structural compliance gap shows up here exactly the way it shows up at facility level. The plant manager reads the headline and assumes the rules loosened. The federal regulatory framework, read in detail, says the rules did not loosen — only the state’s SIP submission calendar shifted. The cost of acting on the headline is measured in NNSR penalty exposure. The cost of reading the detail is a one-hour internal review.

How iSi Helps With This

The “did anything actually change for our permit?” question is the kind of call iSi supports for multi-state operators every week. When a federal action changes the planning posture in an area where you operate but does not change the source-side obligations, the analysis that gets you to a defensible internal answer takes about a day per facility — pull the active permits, confirm the SIP rules in force, document the no-change conclusion, and get it in front of operations before a permit-strategy assumption gets made on partial information.

iSi works inside multi-state environmental teams as augmentation, not replacement — the corporate environmental team retains its judgment role on every decision, and we handle the regulatory tracking, applicability re-analysis, and permit review across the portfolio. For a multi-state operator with one Cleveland facility plus operations in Texas, Colorado, Kansas, or Oklahoma, that is the kind of work that gets folded into the COOP retainer rather than priced as a separate project. If you would like to talk through what the May 14 CDD means for a specific facility in the Cleveland seven-county area, call (316) 264-7050 or use the contact form. We can typically have an applicability review in front of you within a week.