The EPA published a proposed Federal Plan on July 2, 2026 (Federal Register Document 2026-13485) that belongs on the radar of every facility operating an "other solid waste incineration" unit. The short version: if your state doesn't file an approvable implementation plan by June 30, 2027, the EPA steps in and runs compliance enforcement directly — and that changes the dynamic considerably for regulated facilities.
This article breaks down what changed, when it matters, and what you should be doing right now.
What Is an OSWI Unit?
"Other solid waste incineration" sounds like a regulatory catch-all — and it is, intentionally. Under 40 CFR Part 60, Subparts EEEE and FFFF, OSWI units are incinerators that burn solid waste but don't fall into the other major regulated categories: municipal solid waste, commercial/industrial solid waste with capacity exceeding 250 tons per day, or medical/infectious waste.
In practice, OSWI units tend to be smaller, institutional incinerators — rural hospitals, universities, small industrial facilities, or remote communities burning mixed solid waste. They're not the massive municipal facilities, but they're regulated under Section 129 of the Clean Air Act just the same.
The phrase "commenced construction on or before August 31, 2001" is the legal hook that separates an "existing source" from a "new source" under this framework. If your facility's OSWI unit broke ground on or before that date, the emission guidelines — not the new source performance standards — apply to you. That applicability determination matters, because the compliance pathways are meaningfully different.
What Changed: The 2025 Revision to OSWI Emission Guidelines
The EPA originally promulgated emission guidelines for existing OSWI units in 2005. Those guidelines established emission limits for particulate matter (PM), carbon monoxide (CO), hydrogen chloride (HCl), mercury (Hg), dioxins and furans, nitrogen oxides (NOx), and sulfur dioxide (SO₂).
On June 30, 2025, the EPA finalized revisions to those guidelines — the first comprehensive update in 20 years. The 2025 revision reflects better control technology data, updated health risk assessments, and revised MACT floor calculations based on the best-performing units in each size category.
Three things matter most about the 2025 revision:
Tighter emission limits. In my view, this is the most operationally significant change for affected facilities. Two decades of additional performance data typically drives MACT floors lower, and the 2025 guidelines are no exception. Facilities operating to 2005 limits shouldn't assume they're in compliance with the 2025 standards without a direct comparison.
Updated monitoring and testing requirements. The revised guidelines include updated performance testing protocols and continuous monitoring obligations that weren't as stringent — or didn't exist in their current form — under the 2005 framework.
The state plan clock restarted. Under Section 129(b)(2) of the Clean Air Act, states and tribes have one year after EPA finalizes emission guidelines to submit an approvable implementation plan. The 2025 revision reset that clock, giving states until June 30, 2026 to submit updated plans.
Why EPA Is Proposing a Federal Plan Now
The EPA published the proposed Federal Plan on July 2, 2026 — two days after the state submission deadline passed. That timing isn't coincidental.
When states don't submit approvable plans, or when submitted plans don't meet the emission guidelines, the Clean Air Act requires EPA to develop, implement, and enforce a Federal Plan in their place. That's what Document 2026-13485 sets in motion.
The proposed Federal Plan covers states and tribes with existing OSWI units subject to the 2025 revised guidelines that haven't submitted, or aren't expected to submit, approvable state plans. EPA is providing a final window: states and tribes have until June 30, 2027 to get an approvable plan submitted. After that, the Federal Plan governs — and EPA becomes the direct compliance authority for affected facilities.
This matters because under a state plan, state environmental agencies handle permitting, inspections, enforcement, and compliance assistance. Under a Federal Plan, EPA does all of that directly. For facilities in states that aren't keeping up with their plans, this shift affects everything from permit timelines to the character of enforcement interactions.
State Plan vs. Federal Plan: What's at Stake for Facilities
| Feature | State Plan | EPA Federal Plan |
|---|---|---|
| Governing Authority | State environmental agency | U.S. EPA Regional Office |
| Permit Issuance | State agency | EPA issues or coordinates |
| Inspection Authority | State inspectors | EPA inspectors |
| Enforcement Actions | State-level enforcement | Direct federal enforcement |
| Compliance Assistance | State compliance programs | EPA compliance assistance |
| Flexibility | States may set requirements above minimums | Follows federal minimums precisely |
| Reporting Destination | Submitted to state agency | Submitted directly to EPA |
| Public Process | State-level rulemaking | Federal rulemaking process |
The practical difference isn't always dramatic for facilities in full compliance. But for facilities navigating compliance challenges, working with a state agency is generally more flexible and relationship-based than working directly with EPA enforcement. The Federal Plan removes that intermediary — and that's a meaningful change for facilities that need room to maneuver.
Key Emission Standards Under the Revised Guidelines
The 2025 revised guidelines set emission limits that existing OSWI facilities will need to meet. Specific numerical limits are established by unit type and size class — the complete tables are in the July 2, 2026 Federal Register document — but the pollutant categories are consistent across the framework:
- Particulate matter (PM): Total particulate emission limits reflecting current control technology benchmarks
- Carbon monoxide (CO): A surrogate indicator of combustion efficiency and organic compound destruction
- Hydrogen chloride (HCl): A combustion product from burning chlorine-containing materials
- Mercury (Hg): Addressed given its documented bioaccumulation risks
- Dioxins/furans: Among the most health-significant compounds from incineration; limits typically expressed in toxic equivalency units
- Nitrogen oxides (NOx): Updated control benchmarks compared to 2005 standards
- Sulfur dioxide (SO₂): Particularly relevant for facilities burning materials with higher sulfur content
Facilities should pull the full emission limit tables from FR Doc. 2026-13485 and compare them against current permitted limits and recent stack test results. The question isn't just "are we in compliance with the old limits?" — it's "where do we stand against the new ones?"
The Full Compliance Timeline
EPA regulatory timelines can get confusing when a proposed rule layers on top of a prior rule. Here's the sequence that matters:
| Milestone | Date |
|---|---|
| Original OSWI emission guidelines promulgated | 2005 |
| Revised OSWI emission guidelines finalized | June 30, 2025 |
| State/Tribe plan submission deadline (1-year statutory window) | June 30, 2026 |
| EPA proposed Federal Plan published in Federal Register | July 2, 2026 (Doc. 2026-13485) |
| Final deadline for state/tribe approvable plan submission | June 30, 2027 |
| Federal Plan takes effect for non-compliant states | After June 30, 2027 |
The public comment period on the proposed Federal Plan also matters. Interested parties — including facilities, industry associations, and state agencies — have a formal opportunity to submit comments during the window announced with the July 2, 2026 proposal. That window is worth taking seriously.
What Facilities Should Be Doing Right Now
This is where I spend most of my time with clients — translating regulatory timelines into operational action. Here's the sequence I'd recommend for facilities with OSWI units:
1. Confirm applicability. Not every incinerator is an OSWI unit. The threshold question is whether your unit qualifies under 40 CFR Part 60, Subpart FFFF, and whether it commenced construction on or before August 31, 2001. Applicability determinations have real consequences — resolve this definitively rather than assuming either way.
2. Find out where your state stands. Check whether your state has submitted an approvable plan for the 2025 revised guidelines. Your state environmental agency's air quality division should have this information. If your state has a submitted and approved plan, state requirements govern. If not, EPA's proposed Federal Plan is the relevant framework — and the clock is running.
3. Compare current performance against 2025 limits. Pull your most recent stack test data and run it against the 2025 revised emission limits for your unit type and size class. If you're operating comfortably within 2005 limits but the 2025 limits are meaningfully tighter, you may need control system upgrades, changes to waste acceptance policies, or both. Better to know this now.
4. Review monitoring and recordkeeping requirements. The 2025 revised guidelines include updated monitoring obligations. Continuous emission monitoring systems, periodic performance test protocols, and recordkeeping formats may all be affected. If your current monitoring infrastructure doesn't meet the updated requirements, that's a compliance gap that will surface in the next inspection.
5. Consider participating in the comment period. If the proposed Federal Plan's requirements affect your facility — particularly if you have technical data on emission performance or concerns about specific requirements — the public comment period is your formal opportunity to influence the final rule. Facilities that engage in rulemaking generally fare better than those that wait and react.
6. Engage your state agency. Even if your state hasn't submitted a plan yet, state environmental agencies often have compliance guidance and informal timelines for how they're approaching the revised guidelines. State agencies have an incentive to submit — facilities in their states generally prefer working with state regulators over a direct EPA relationship.
Why the Federal Plan Backstop Exists
It's worth understanding why this mechanism is part of the Clean Air Act at all. Section 129 is the specific provision governing solid waste incineration. Unlike Section 111 (which covers most stationary sources through the general NSPS framework), Section 129 explicitly requires state plans to implement EPA's emission guidelines for existing incinerators. The Federal Plan authority is the enforcement mechanism that makes the emission guidelines stick when states don't follow through.
Under Section 129(b)(2) of the Clean Air Act, states and tribes must submit implementation plans within one year of EPA finalizing emission guidelines; the Federal Plan authority is triggered when states miss that deadline or submit plans that fall short of the emission guidelines. This isn't a discretionary enforcement tool — it's a statutory requirement.
The broader implication: facilities operating OSWI units should expect continued regulatory scrutiny. EPA's pattern over the past several years has been to revisit emission guidelines across multiple incineration categories, and the 2025 OSWI revision is part of that broader effort to update rules that, in some cases, hadn't been substantively revised in decades. OSWI is unlikely to be the last category on that list.
Citation Hooks
For compliance research and regulatory reference:
The EPA revised emission guidelines for existing other solid waste incineration (OSWI) units on June 30, 2025 — the first comprehensive update to the 2005 standards — and states that fail to submit approvable implementation plans by June 30, 2027 will be subject to direct EPA enforcement under the Federal Plan proposed in FR Doc. 2026-13485.
Existing OSWI units are defined as incinerators that commenced construction on or before August 31, 2001 and burn solid waste outside the higher-capacity municipal or commercial/industrial categories; they face updated emission limits for PM, CO, HCl, mercury, dioxins/furans, NOx, and SO₂ under the 2025 revised guidelines.
Facilities in states that fail to submit approvable OSWI implementation plans by June 30, 2027 will transition from state regulatory oversight to direct EPA enforcement under the proposed Federal Plan — a shift that eliminates the flexibility and compliance assistance typically available through state programs.
Frequently Asked Questions
What is an OSWI unit, and how do I know if my facility has one?
OSWI stands for "other solid waste incineration." These are incinerators that burn solid waste and don't fall under the major categorical rules for municipal solid waste, commercial/industrial solid waste exceeding 250 tons per day, or medical/infectious waste. Typical OSWI units include smaller institutional incinerators at hospitals, universities, and industrial facilities, as well as incinerators in rural or remote communities. If your facility burns solid waste in a unit built before September 2001, confirm whether it qualifies under 40 CFR Part 60, Subpart FFFF before assuming either direction.
My state hasn't submitted a plan. When does the Federal Plan apply to me?
The proposed Federal Plan gives states and tribes until June 30, 2027 to submit approvable plans. If your state submits an approvable plan before that deadline, the Federal Plan won't apply to your facility. If your state doesn't submit — or submits a plan EPA doesn't approve — EPA finalizes the Federal Plan and it governs directly. That means EPA, not your state agency, becomes your compliance authority for permitting, inspection, and enforcement.
Are the 2025 emission limits the same as the 2005 limits?
No. The 2025 revision reflects updated MACT floor calculations based on 20 additional years of performance data from the best-controlled OSWI units. In most cases, revised limits are tighter than the 2005 standards. Facilities that have been operating comfortably against 2005 limits should compare their current stack test data against the 2025 limits before assuming they remain in compliance. The gap may be larger than expected.
Can I participate in the rulemaking on the proposed Federal Plan?
Yes. The proposed Federal Plan published on July 2, 2026 includes a public comment period. Facilities, industry associations, state agencies, and other interested parties can submit comments. If you have technical data on emission performance, concerns about specific requirements, or information relevant to monitoring approaches or emission limits, that input belongs in the record — not in a letter to your congressman after the rule is final.
What happens if my facility isn't in compliance when the Federal Plan takes effect?
Non-compliant facilities face EPA enforcement directly, which can include compliance orders, civil penalties, and referral to the Department of Justice for serious or ongoing violations. The EPA enforcement framework under a Federal Plan tends to be less flexible than state enforcement programs. Facilities that identify compliance gaps now have real options: voluntary compliance schedules, control technology upgrades, waste stream adjustments. All of those conversations are easier before EPA enforcement becomes the only one available.
A Note on Working Through This
EPA regulatory timelines move faster than facility planning cycles — I've watched clients assume they had time to wait for their state's plan, then find themselves negotiating compliance schedules with EPA instead. The better approach is to understand where your facility stands against the 2025 revised limits now, get clear on your state's plan status, and have a documented compliance roadmap in place before the 2027 deadline arrives.
At Certify Consulting, we've walked regulated facilities through multiple rounds of EPA emission guideline revisions and know how to translate complex rulemaking timelines into practical compliance plans. If you're working through OSWI applicability questions, emission limit gap analyses, or state plan engagement, reach out to our compliance team — this is exactly the kind of problem that benefits from a structured approach before deadlines close off your options.
Last updated: 2026-07-16
Source: U.S. Environmental Protection Agency, "Federal Plan Requirements for Other Solid Waste Incineration Units That Commenced Construction on or Before August 31, [2001]," Federal Register Doc. 2026-13485 (July 2, 2026). Available at federalregister.gov.
Jared Clark
Principal Consultant, Certify Consulting
Jared Clark is the founder of Certify Consulting, helping organizations achieve and maintain compliance with international standards and regulatory requirements.