The Connecticut Department of Energy and Environmental Protection (DEEP) has issued a new general permit for remediation contractors, known as the General Permit to Act as a Contractor to Contain or Remove or Otherwise Mitigate the Effects of Certain Releases (Registered Existing Release Response Contractor) (Remediation GP). This new Remediation GP supplements the well-established spill response contractor program under Connecticut General Statutes § 22a-454 and addresses a source of ongoing confusion for remediation professionals.

By statute, a permit is required for any person engaged in the business of “collecting, storing or treating waste oil or petroleum or chemical liquids or hazardous wastes or of acting as a contractor to contain or remove or otherwise mitigate the effects of discharge, spillage, uncontrolled loss, seepage or filtration of such substance or material or waste…” Conn. Gen. Stat. § 22a-454(a). 

For many years, DEEP has maintained an individual permit program under § 454 covering emergency spill response contractors. Remediation contractors (i.e., those who physically remove impacted soil during a remediation project) have not necessarily held such spill response permits. Because spill response contractors respond to emergencies, there are several requirements (e.g., 24-hour availability, access to boats, and specialized equipment) relevant to emergency spill response that are not relevant to remediation of pre-existing soil contamination.  In recent years, however, DEEP has increasingly taken the position that the remediation of pre-existing soil contamination requires a spill response permit. Given the mismatch between the spill response permit requirement and the soil remediation business, the spill response permit was not a comfortable fit for soil remediation contractors.

The new Remediation GP is intended to bridge the gap between the requirements applicable to spill response contractors and the reality of soil remediation projects. Registrants under the Remediation GP are permitted to contain, remove, or otherwise mitigate pre-existing contamination of soil (including saturated soil below the groundwater table) with waste oil, petroleum, chemical liquids, and/or hazardous waste at sites being investigated or remediated under specified statutory and regulatory programs including:

  • State Brownfields Programs:
    • Brownfield Liability Relief Program (Conn. Gen. Stat. § 32-764)
    • Abandoned Brownfields Program (Conn. Gen. Stat. § 32-768)
    • Brownfield Remediation and Revitalization Program (Conn. Gen. Stat. § 32-769)
    • Municipal Brownfield Liability Relief Program (Conn. Gen. Stat. § 22a-133ii)
    • Voluntary Remediation Programs (Conn. Gen. Stat. §§ 22a-133x, 22a-133y);
  • The Transfer Act (Conn. Gen. Stat. § 22a-134 et seq.)
  • After March 1, 2026, the Release-Based Cleanup Regulations (Conn. Gen. Stat. § 22a- 134tt et seq.; Regulations of Connecticut State Agencies (R.C.S.A.) § 22a-134tt-1 et seq.); and
  • The Comprehensive Environmental Response, Compensation, and Liability Act (CERLCA, 42 U.S.C. § 9601 et seq., commonly known as “Superfund”), though as discussed below, new releases reportable under CERCLA are not eligible.

Such soil remediation must be conducted under the supervision of a licensed environmental professional (LEP) in regular communication with the registrant, though a LEP does not needto be physically present for the duration of the work. Such soil remediation must also be performed in compliance with safety regulations and by personnel using appropriate personal protective equipment.

Registrants under the Remediation GP are not permitted to address the following types of releases regulated under the:

  • Connecticut Release Reporting Regulations (R.C.S.A. § 22a-450-1 et seq.), which relate to reporting of present-day emergent releases;
  • Federal Release Reporting Regulations (CERCLA or the Emergency Planning and Community Right-to-Know Act (EPCRA), 42 U.S.C. § 11001 et seq.);
  • Connecticut Underground Storage Tank Regulations (R.C.S.A. § 22a-449(d)-1 et seq.);
  • Permits issued under Conn. Gen. Stat. § 22a-449(b) to construct and operate a marine terminal; and
  • Federal Toxic Substances Control Act (TSCA) (15 U.S. Code § 2601 et seq.), i.e., certain releases containing polychlorinated biphenyls (PCBs).

Any release subject to one of the above programs must be addressed by a spill response contractor holding an individual permit under General Statutes § 22a-454. In addition, registrants may not contain, remove, or otherwise mitigate releases from surface water or groundwater, as such activities also require a spill response permit. The Remediation GP specifies, however, that installation, operation, and maintenance of in situ remediation systems (e.g., groundwater pump-and-treat, air sparging) do not require a permit.

As noted above, the new Remediation GP is relevant to activities undertaken in connection with Connecticut’s new Release-Based Cleanup Program, which will go into effect a few short months from now on March 1, 2026. A number of recent and forthcoming posts on this blog discuss in detail various important aspects and considerations related to the new Release-Based Cleanup Program and associated regulations.

This is the fifth in a series of blog posts discussing key features of Connecticut’s new release-based cleanup regulations (the “RBCRs”), R.C.S.A. § 22a-134tt-1 et seq. 

The last post in the RBCR series discussed reporting of new releases under Connecticut’s March 2022 spill regulations. This post discusses immediate response actions required for new releases (and especially serious existing releases) under the RBCRs.   

Spill Response Today

As previously discussed, the spill regulations at R.C.S.A. 22a-450-1 et seq., provide reporting requirements for new releases. They also require responsible parties to “act immediately to contain and remove or otherwise properly mitigate such release” to DEEP’s satisfaction “using properly trained personnel.” Some facilities employ in-house personnel properly trained to respond to some releases. Anyone in the business of responding to such releases must hold a spill response contractor permit under Conn. Gen. Stat. §22a-450.

When DEEP personnel and spill response contractors respond to the location of a release, they take immediate action to contain or remove the material released. Once this immediate emergency condition has been corrected, the release is marked “closed” in DEEP’s spill incident database. That said, such release may not have been investigated and remediated to the same standards as existing releases, and compliance with remediation standards may not have been achieved. One of the most significant changes being implemented through the RBCRs is to integrate the characterization, remediation, and closure process for both old and new releases.

Immediate Actions Under RBCRs

The RBCRs provide new requirements for actions that must be taken in the immediate wake of a spill (called an “emergent reportable release” or “ERR” under the RBCRs). These requirements also apply to the discovery of a “significant existing release” or “SER,” i.e., an especially serious existing release like a contaminated drinking water well. Significant existing releases are discussed in more detail in the third post in this series.)

Immediate actions must begin upon discovery of the emergent reportable release or significant existing release, and no later than two hours after discovery. For ERRs, such required actions include removing the release from the land and waters of the state “to the maximum extent practicable” and removing the release from improved surfaces like pavement and concrete. For SERs, it may not be possible to remove the material released right away (as it may have spread over time) and necessary actions will depend upon the site-specific and material-specific circumstances. For both SERs and ERRs, the responsible party must implement measures to prevent migration of the release (e.g., placement of barriers) and must identify and eliminate the source of the release. The RBCRs also provide specific actions that must be taken in specific circumstances. (For example, an alternate water supply must be provided when a drinking water well has been contaminated.)

Closure and/or Longer-Term Remediation

Some emergent reportable releases to improved surfaces (like an asphalt road) can quickly be cleaned up, and some emergent reportable releases to soil can quickly be addressed by excavating impacted soil before the release has an opportunity to spread. For these types of releases, the required closure documentation can be prepared by a new class of environmental professionals, the Permitted Environmental Professional or “PEP.” It is expected that PEPs may include some of the same people and businesses presently permitted as spill response contractors. Training and licensing materials for PEPs are still under development, and more information will be shared when it is available. 

Other releases that cannot be closed by a PEP will be addressed by the existing cohort of Licensed Environmental Professionals or “LEPs.”

Next Steps

When an ERR or SER cannot be fully remediated within one year (for example, because it has impacted groundwater), it will be characterized and remediated under the process set forth in the RBCRs. Those characterization and remediation steps will be discussed in future posts.

This is the fourth in a series of blog posts discussing key features of Connecticut’s new release-based cleanup regulations (the “RBCRs”), R.C.S.A. § 22a-134tt-1 et seq. 

The new RBCRs set forth requirements for the characterization, remediation, and closure of both old and new releases. The last few posts in this RBCR overview series have related to the discovery and reporting of old or existing releases. This post provides a refresher of the spill regulations that went into effect in March of 2022 (R.C.S.A. § 22a-450-1 et seq.), as those spill regulations provide the requirements for reporting new releases.

Reporting New Releases

By statute, the person responsible for a vessel, vehicle or site which experiences the “discharge, spillage, uncontrolled loss, seepage or filtration of oil or petroleum or chemical liquids or solid, liquid or gaseous products, or hazardous wastes” which pose “a potential threat to human health or the environment” must immediately report the release to DEEP. Regulations went into effect in March of 2022 that set forth the specific parameters regarding such reporting.

The reporting thresholds depend upon the material that has been released. A release must be reported if it involves five or more gallons of petroleum, or one and a half gallons or ten pounds of a material other than oil or petroleum. Releases below these thresholds also are reportable unless the release has been contained and removed, or otherwise properly mitigated, within two hours after discovery.

Certain releases are always reportable, regardless of the quantity released. These include:

  • A release that enters a wetland, waterway, sanitary sewer, storm sewer, or catch basin;
  • A release from an underground storage tank;
  • A release of unknown material;
  • A release of material that contains PCBs or PFAS; and
  • A release of material that contains a listed extremely hazardous substance.

Other types of releases are exempt from reporting. These include:

  • A release authorized by law, regulation, or permit;
  • A release from a consumer or industrial product being used as intended (for example, VOCs released from paint as it dries); and
  • Pesticides and fertilizers applied in a manner consistent with their labels.

DEEP’s website provides reporting instructions. The first step is a call to DEEP’s 24-hour emergency phone line (1-866-DEP-SPIL/1-866-337-7745).

Applicability of the RBCRs

The spill regulations focus on reporting, and the RBCRs provide detailed requirements setting forth what must be done after a new release is reported, as we will discuss in the next post. That said, not all releases reportable under the spill regulations are subject to the RBCRs.

The RBCRs apply to releases to the land and waters of the state, but not all reportable spills reach the land and waters of the state. The RBCRs provide that the following types of reportable releases are not subject to the RBCRs:

  • A release to the air;
  • A release to secondary containment, when the release does not contact soil;
  • A release indoors, provided that it does not come into contact with soil and substantially all of the material released is removed from any surface to which it was released no more than two hours after discovery.  For example, suppose a grocery store mishap results in several gallons of dish soap being spilled on the linoleum floor.  Such a release would be reportable but would not require documentation under the RBCRs if it is cleaned up within two hours.

Next Steps

After a new release is reported, certain immediate response actions are required, as we will discuss in our next post. Any contamination still present after the immediate response actions are completed must be characterized and remediated through the same process applicable to existing releases. These characterization and remediation requirements will be covered in future posts.

This is the third in a series of blog posts discussing key features of Connecticut’s new release-based cleanup regulations (the “RBCRs”), R.C.S.A. § 22a-134tt-1 et seq. 

After a release has been “discovered” (see last post) the next step under the RBCRs is evaluating if and when that release must be reported.  This post, and the companion Release Report episode, discusses reporting timelines for different types of releases, in decreasing order of seriousness.

Significant Environmental Hazards and Significant Existing Releases

At present, the Significant Environmental Hazards statute (Conn. Gen. Stat. § 22a-6u) requires reporting and mitigation of especially serious contamination like impacted drinking water wells and soil with concentrations of contaminants detected at 15 times the remediation standard. The Significant Environmental Hazard program will remain in place for sites in brownfields programs and other releases not subject to the RBCRs.

For releases subject to the RBCRs, especially serious releases are considered “significant existing releases.” Similar to the familiar categories of significant environmental hazards, significant existing releases include releases that have impacted a drinking water well (or groundwater within 500 feet of a drinking water well); surface soil contaminated at 15 or 30 times remediation standards (depending on the contaminant); groundwater contamination that threatens to cause indoor air contamination; and groundwater contamination at 10 times the surface water protection criteria located within 250 feet of surface water.

A significant existing release has been “discovered” when anyone becomes aware of the release, such person does not need to be the creator or maintainer. A person other than the creator or maintainer who discovers a significant existing release must notify such creator or maintainer within one business day either directly or through their client (if hired for due diligence purposes or otherwise by someone other than the owner with a right to access the property).  For releases known to be impacting drinking water wells, the creator/maintainer must be notified within six hours.

Once the creator/maintainer of a significant existing release has knowledge of such release, they must notify DEEP within 24 hours if such release is impacting a drinking water well, or within 72 hours otherwise. Such significant existing releases must be addressed promptly, as a forthcoming blog post will cover.

Other Releases – 120-day and 365-day Deadlines

Releases that are not significant existing releases must be reported to DEEP within 120 days after discovery if:

  • Laboratory analysis indicates the presence of contaminants at more than double the relevant remediation standard for any constituent with a remediation standard. For petroleum contamination, this 120-day deadline applies only if the release has impacted at least two cubic yards of soil.
  • Non-aqueous phase liquid (e.g., oil) is present in groundwater at a measured thickness of one-eighth inch.
  • Laboratory analysis indicates the presence of a contaminant at more than double the additional polluting substances criteria (if an additional polluting substances criterion can be calculated) or indicates the presence of any amount of contamination if no additional polluting substances criterion can be calculated.

Releases that do not fit into one of the 120-day reporting categories must be reported to DEEP within 365 days, except for low-level soil contamination as discussed below. Reporting can be avoided, however, if the contamination is remediated and a closure report is prepared before the reporting deadline occurs (i.e., either 120 or 365 days).  The closure process will be discussed in a future post.

Incidental Releases – No Report Necessary

As noted in the last post about discovery, any detection of contaminants above the laboratory reporting limit constitutes discovery of a release, even in minute quantities. That said, discovery in soil of constituents other that PFAS and VOCs at less than or equal to 25 percent of the remediation criterion is considered an incidental release and is not reportable. Note that this only applies to releases detected in soil—any release detected in groundwater is reportable unless it meets one of the specified exemptions discussed in the last post.

Next Steps

After a release is reported, it must be investigated and characterized. These investigation and characterization steps apply to both new releases and the existing releases. Characterization requirements will be discussed in the fourth post in this series. The next post and episode will discuss reporting of new releases.

This is the second in a series of blog posts discussing key features of Connecticut’s new release-based cleanup regulations (the “RBCRs”), R.C.S.A. § 22a-134tt-1 et seq. 

Under the new RBCRs, the obligation to characterize and, if needed, remediate pre-existing contamination begins with the “discovery” of that contamination by a person who created or is maintaining the contamination (e.g., the owner of the property on which the release is located). This blog post, and the companion Release Report episode, discusses what it means to “discover” existing contamination under the RBCRs.

Under the RBCRs, discovery of a release to the land and waters of the state “occurs when a person who created or is maintaining an existing release has knowledge of such release” subject to some exemptions discussed below. As discussed in our last post, for practical purposes the “maintainer” can be read as the property owner plus tenants that have not discharged their responsibility to notify their landlords. Except for especially serious contamination as discussed below, a release is not “discovered” until the creator or maintainer knows about it. As we will discuss in a future blog post, there is an opportunity for prospective buyers doing pre-purchase due diligence to learn about site conditions without triggering reporting obligations for the current owner.

Discovery

A creator or maintainer of an existing release can discover such release in one of three ways:

Laboratory analysis of soil, groundwater, sediment, or soil vapor that indicates concentrations of such substances above the laboratory reporting limit. Note that this does not require that any remediation standard be exceeded—a release has been discovered if any contamination has been detected, even in minute concentrations.  Reporting requirements, including carve-outs for low-level contamination, will be discussed in the next blog post.

Observed presence of non-aqueous phase liquid (e.g., oil visible on the surface of groundwater)

Multiple lines of evidence of a release are discovered in the course of an investigation. The regulations provide that such evidence can include information about the geographical area (e.g., aerial photos depicting a stockpile or lagoon, maps depicting site features, witness accounts of site features or activities); field screening tools; observed staining; odors; indoor air samples indicating the intrusion of soil vapor; and visible asphalt, solid waste, and other non-native materials. While DEEP’s language defining what it means for multiple lines of evidence to be “discovered in the course of an investigation” did not make it into the final version of the regulations, DEEP provided an explanation of its thinking in its response to comments received on a draft of the regulations. Such an investigation can include an environmental Phase I, but it can also include a geotechnical investigation, survey, or any other inspection by several different types of professionals for the purpose of identifying pollution, planning for construction or redevelopment, or disposing or discharging soil, sediment, or groundwater, or complying with any federal, state, or locally issued permit or authorization. DEEP might provide additional guidance on this point as the RBCRs are implemented.

In addition to the above methods for the creator/maintainer of a release to discover such release, there are a few ways that a release could be discovered by someone else. Especially serious contamination like a contaminated drinking water well (known as a “significant existing release” in the RBCRs) can be discovered by anyone (reporting requirements for significant existing releases will be discussed in the next post). In addition, if someone is investigating the source of contamination on their property, and identifies a likely source on a different property, they can provide information on the release to the owner of the suspected source property. The owner of the suspected source property will be presumed to be maintaining a release until they have characterized the suspected source area and confirmed that there is no such release.

Exemptions

The regulations provide that certain types of contamination do not constitute a discovered release subject to the RBCRs. Releases from underground storage tanks subject to Conn. Gen. Stat. 22a-449(d) are not subject to the RBCRs and instead must be addressed through the underground storage tank regulations. Substances that are present because of certain authorized discharges, automobile exhaust and fertilizers and pesticides applied consistent with their labels are not considered discovered releases subject to the RBCRs. Other targeted exemptions (e.g., for recreational fire pits) exist as well.

The statute provides that a release has not been discovered if the “only evidence of such release is data available or generated” before March 1, 2026. While DEEP has not offered any guidance on what it means for the “only evidence” to be such data, it does mean that there is no obligation to review reports buried deep in the filing cabinet and notify DEEP of releases on Day One of the program. Such releases would be discovered, and must be reported, if and when they are re-discovered in the future.

Next Steps

Once a release is discovered, the creator/maintainer has responsibilities to address such release under the RBCRs. The first step, reporting, will be discussed in the next post.

Following the Trump administration’s abrupt cancelation of the Revolution Wind project at the end of August, Revolution Wind LLC, a joint venture between Ørsted and Skyborn Renewables, filed suit in the U.S. District Court for the District of Columbia seeking to prevent enforcement of the stop work order. Revolution Wind contends that the order was motivated by political partisanship and that the administration’s claimed “national security” justification was arbitrary and capricious. 

On a parallel track, Connecticut and Rhode Island brought a similar action in Rhode Island District Court, claiming that the cancellation order was baseless and harmed ratepayers in both states, which were to have been the beneficiaries of the 704 MW of anticipated generation from the project. Revolution Wind had completed all state and federal reviews, including the Department of Defense, and was approximately 80% completed at the time of the order.

The Trump administration has also announced its intention to revoke federal approvals for New England Wind, which is not yet under construction, and other projects off the coast of Maryland. Revocation of these permits would complete the targeting of active and pending offshore projects off the coasts of Maryland, Massachusetts, New York (with the exception of Empire Wind, which was able to reverse a revocation order), New Jersey, and Rhode Island. Coastal Virginia Offshore Wind, a 60% completed offshore project that has maintained the support of Republican Virginia Governor Glenn Youngkin, has thus far been allowed to proceed.

Connecticut’s environmental remediation laws are about to change significantly on March 1, 2026. This blog series, and the companion Release Report video series, will highlight key features of the new release-based cleanup regulations (referred to as “RBCRs”) so interested parties can get ready.

Background

At present, much of the environmental remediation in Connecticut is driven by the Connecticut Transfer Act (Conn. Gen. Stat. § 22a-134 et seq.). The Transfer Act requires site-wide environmental investigation and potential remediation when an “establishment” is “transferred.” Establishments include specifically-identified types of businesses (e.g., dry cleaners, vehicle body repair shops, furniture strippers) and sites or businesses that generated 100 kg of hazardous waste in any one month since November 1980.  

Since the Transfer Act is triggered by real estate or business transfers, one could avoid the Transfer Act by avoiding becoming involved in a transfer.  Unfortunately, that kills deals and chills economic development. Furthermore, many sites that have not been transferred have not been subject to clear investigation and remediation triggers, leaving contaminated sites with no obvious impetus for anyone to clean up. Both of these factors lead to a pivot away from the Transfer Act through Public Ac 20-09 and the implementing regulations that followed.

New Law

After March 1, 2026, new transfers of establishments will no longer require action under the Transfer Act. Instead, Public Act 20-09 (codified as Conn. Gen. Stat. § 22a-134pp et seq.) requires releases to be investigated and remediated when they occur or are discovered, not as part of a mandated site-wide program.  Specifically, § 22a-134qq provides that “[n]o person shall create or maintain a release to the land and waters of the state in violation of” the statute. 

While it appears that the word “create” will be understood in its ordinary sense, the word “maintain” deserves attention. The RBCRs provide that a person is “maintaining” a release if they own a parcel of land on or under which such release (or portion of the release) is located. If a tenant discovers an existing release, they must notify their landlord or may be deemed to be maintaining the release themselves. In other words, any business with operations in Connecticut has the potential to “create” a release, and any property owner in Connecticut has the potential to “maintain” a release on its property. 

The spill reporting regulations at R.C.S.A. 22a-450-1 et seq. set forth the procedure for reporting newly occurring releases, with the new RBCRs providing new requirements for cleanup and closure. For existing releases, obligations to investigate and remediate begin with the “discovery” of such release. The next blog post, and companion episode, in this series will discuss in more detail what it means to discover an existing release.

What’s Next?

Between now and March 1, there are a number of things that manufacturers, property owners, developers and others should be thinking about as they prepare for the implementation of the RBCRs. Upcoming blog posts and episodes will discuss reporting requirements, closure documentation, due diligence considerations and more.  If you have any questions or suggestions, please email me at escott@rc.com.

A new video podcast series is coming to Environmental Law +! The Release Report: Inside Connecticut’s Release-Based Cleanup Regulations will highlight the transformative changes set to unfold with the replacement of the nearly 40-year-old Transfer Act.

Join me, Emilee Mooney Scott, an Environmental partner and member of the Working Group convened under Public Act 20-09, as I explore Connecticut’s evolving environmental landscape with the implementation of the Release-Based Cleanup Regulations set to take effect on March 1, 2026.

Don’t miss the first episode dropping on Wednesday, September 10!

In the meantime, check out the preview for The Release Report (below) and my related post, “It’s Official, The Transfer Act Will be ‘Sunset’.”

On Friday, August 22, 2025, the Trump administration announced the cancellation of the Revolution Wind project located off the south coast of Rhode Island, east of Block Island. At the time of the stop work order, the project, based out of the State Pier in New London, Connecticut, was approximately 80% complete with foundations in place and 45 of 65 turbines installed. Revolution Wind was slated to provide 304 MW of power to Connecticut and 400 MW of power to Rhode Island. Following the completion of the project, the State Pier was poised to take delivery of parts for Sunrise Wind, an 84-turbine project off the coast of Long Island with the capacity to provide 924 MW of renewable energy. Ørsted, the beleaguered developer of both projects, announced that it would comply with the order while evaluating its options and continuing to secure funding for Sunrise Wind. Connecticut’s federal delegation questioned the basis for the stop-work order, which referenced unspecified national security interests.

The cancellation of Revolution Wind is reminiscent of the administration’s April 2025 stop work order for the Empire Wind project off the coast of Long Island, which was under development at the time. There, the U.S. Department of the Interior ultimately reversed its order following an intensive lobbying effort by Equinor ASA, the developer, which had coordinated with New York federal, state, and city officials to get the project back on track. 

Elsewhere, the lawsuit brought in a Massachusetts federal court by a coalition of 17 states and the District of Columbia following the Trump administration’s January 20, 2025 executive order blocking federal permits for all new offshore wind development continues.  Opposition briefs to summary judgment motions were filed on August 22, 2025.  The plaintiffs argue that the administration’s “indefinite, across-the-board suspensions are arbitrary, capricious, or contrary to law” under the Administrative Procedure Act. The Government contends that the U.S. Department of Interior’s decision to follow an executive directive is a “quintessential non-final agency action” that is not subject to judicial review.

After a few decades of uncertainty and “it’s-alive-it’s-dead-it’s-alive” swings, EPA’s “once in, always in” (OI/AI) policy is once again dead. And this time, it seems very dead.

On June 20, 2025, President Trump signed a Congressional Review Act (CRA) resolution that rejects a September 2024 rule adopted by the Biden EPA that had revived a narrowed version of OI/AI.  

Given its long and controversial life and its little-heralded demise, it seems fitting to give OI/AI a eulogy.

OI/AI began life as an internal EPA policy memo in 1995. The policy provided a complex interpretation of “emits or has the potential to emit” as used in the definition of a “major source” of federally-designated hazardous air pollutants (HAPs): if a facility’s potential to emit HAPs ever exceeded “major source” thresholds after the first compliance date of any substantive requirements of a “major source” HAP standard applicable to that facility, the facility must comply “permanently” with such standard and other requirements for HAP “major sources,” even if the facility later were to reduce its potential emissions below the thresholds. In other words: once in, always in. For more background, see our prior articles here and here.

Over the years, the policy met increasing criticism. While the policy had the well-intentioned goal of reducing HAP emissions, the basis for it in the Clean Air Act (CAA) was not apparent. In essence, the policy was an extremely expansive interpretation of “emits or has the potential to emit” in the CAA’s definition of “major source” of HAP in CAA § 112(a)(1), with little to no support from the statutory text. This interpretation was a far cry from a plain-English reading of simple present-tense verbs. It was also at odds with the EPA’s plain-English reading of similar language used to define a “major source” for other CAA programs.  

Further imperiling its longevity, the OI/AI policy was based solely on an internal EPA memo, without Administrative Procedure Act notice-and-comment rulemaking. The result, undoubtedly not intended, was a classic “trap for the unwary” that added further complexity to the CAA and introduced unpleasant surprises in regulatory compliance inspections and transactional due diligence.

The surge of regulated party discontent eventually led to a regulatory tug-of-war. The Bush II EPA made initial moves to undo the OI/AI policy, but these stalled. In 2018, however, the Trump I EPA withdrew the policy as not supported by the CAA, and then revised CAA regulations to expressly allow a facility to shed “major source of HAP” status by reducing its potential emissions. But OI/AI wasn’t dead yet. In September 2024, the Biden EPA adopted a final rule containing a more qualified version of “once in, always in” for facilities that emit certain higher-risk HAPs. That regulation has now been deep-six’ed by the June 2025 CRA resolution.

Per the CRA, future efforts to revive a similar OI/AI regulation would require Congressional approval. A revival also would likely face hostile judicial terrain, particularly in a post-Chevron/Loper Bright world (as many are aware, the Loper Bright decision overruled Chevron’s holding that where a statute is ambiguous, courts should give significant deference to the implementing agency’s interpretation). Even under Chevron, it’s not clear that the OI/AI policy would have survived: it’s not at all certain that the CAA language “emits or has the potential to emit” is ambiguous, so EPA’s interpretation seems unlikely to have received judicial deference under Chevron. A revived version of OI/AI would also need to run a gauntlet of the Supreme Court’s now-dominant textualism and skepticism regarding expansive statutory interpretations by agencies that substantially broaden their power. 

Never say never – but this time, OI/AI for major sources of HAP seems dead and buried.