SB 3836 amends Section 179B of the Clean Air Act to treat emissions originating outside the United States — including emissions from natural events — as a potential basis for excluding an area from nonattainment designation for a new or revised NAAQS if a State can show the area would be in attainment but for those emissions. The bill also adds a new Section 179A that bars application of certain sanctions or fees for Severe/Extreme ozone and Serious particulate-matter nonattainment areas when a State demonstrates that failure to attain results from outside emissions, exceptional events, or mobile-source emissions beyond the State's control.
The changes shift the focus from automatic regulatory consequences to a demonstration regime: states must convince the EPA Administrator that international or uncontrollable sources caused the shortfall, and renew that showing every five years. For states near borders, downwind regions affected by wildfire or volcanic plumes, and regulated industries within those states, this bill alters the enforcement landscape by limiting designations and penalties when attribution to sources beyond state and national control is established.
At a Glance
What It Does
The bill inserts language into 179B specifying that ‘‘emissions emanating from outside of the United States (regardless of whether such emissions result from human activity)’’ can be treated as beyond a State’s control for purposes of nonattainment analysis and adds a new Section 179A that makes sanctions and fee provisions inapplicable where a State demonstrates such external contributions (or exceptional events or uncontrollable mobile-source emissions) caused the nonattainment. It requires renewal of that demonstration at least once every five years.
Who It Affects
State environmental agencies (particularly border and island states), EPA regional offices that make designation and enforcement decisions, industries regulated under state implementation plans (SIPs), and communities downwind of wildfires or transboundary pollution. It also affects manufacturers of mobile-source controls because the bill explicitly references mobile emissions as a potential beyond-control category.
Why It Matters
This bill changes the compliance and enforcement calculus by substituting a demonstrable attribution standard for automatic designation and sanction triggers. Professionals should care because it alters the risk of federal sanctions, shifts evidentiary burdens onto states and EPA, and creates recurring administrative duties and technical modeling requirements to preserve sanction relief.
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What This Bill Actually Does
SB 3836 modifies how the Clean Air Act treats pollution that originates beyond U.S. borders or from natural phenomena. It amends Section 179B so that foreign emissions — whether caused by people or by nature — can be treated as outside a State's control when determining whether an area would meet a revised or new national ambient air quality standard (NAAQS) if those external emissions were absent.
The bill adds an explicit subsection preventing EPA from designating an area as nonattainment for a new or revised NAAQS where the State demonstrates the area would be in attainment but for those external contributions.
The bill also inserts a new Section 179A into Part D to control when federal sanctions and fee authorities kick in for high-class nonattainment areas. Under 179A, if a State shows that failure to meet ozone or particulate standards stems from emissions emanating from outside the nonattainment area, from an exceptional event, or from mobile-source emissions the State cannot reduce, then sanctions under sections 179 or 185 cannot be applied.
The State must prove that it has implemented all measures within its authority to control mobile-source emissions before claiming that they are "beyond control." The statutory carve-outs are expressly limited to sanctions and fees; the bill does not alter a State's ongoing obligation to pursue measures to attain the NAAQS.Practically, the bill creates a recurring process: States must make an initial demonstration to the Administrator that external or uncontrollable emissions caused the nonattainment condition and then renew that showing at least once every five years to maintain exemption from sanctions. That places a new, sustained evidentiary and administrative task on states and EPA regional offices, including air-quality monitoring, source attribution analyses, and possibly cross-border data sharing or modeling.
The bill keeps the underlying NAAQS intact, but it narrows the scenarios in which federal enforcement consequences apply.
The Five Things You Need to Know
The bill adds the phrase "regardless of whether such emissions result from human activity" to Section 179B, explicitly including natural phenomena (e.g.
wildfire smoke, volcanic ash) in the pool of emissions that can be treated as beyond control.
It creates a new Section 179A that prevents application of sanctions or fees under Sections 179 and 185 for Severe/Extreme ozone or Serious particulate-matter areas when a State demonstrates the shortfall is due to specified external or uncontrollable sources.
A State must "establish to the satisfaction of the Administrator" that an area would be in attainment but for emissions from outside the United States to avoid a nonattainment designation under the new subsection added to 179B.
To keep sanction and fee relief under Section 179A, a State must renew its demonstration at least once every five years, creating a recurring administrative and scientific obligation.
Section 179A clarifies that an exemption from sanctions does not eliminate a State’s underlying duties under the Clean Air Act to adopt and implement measures to attain the NAAQS.
Section-by-Section Breakdown
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Short title
Establishes the Act’s short title as the "Foreign Emissions and Nonattainment Clarification for Economic Stability Act" or the "FENCES Act." This is purely nominative and has no operational effect on regulatory practice, but it frames the bill’s intent to address foreign-origin and uncontrollable emissions in the CAA.
Treats foreign emissions, including natural events, as beyond control
Amends existing Section 179B by inserting parenthetical language to make clear that emissions "emanating from outside of the United States (regardless of whether such emissions result from human activity)" count as emissions beyond a State's control. That expansion explicitly brings natural transboundary events — not just foreign industrial emissions — into considerations for attainment determinations. The practical implication is that States can seek to exclude the impact of such emissions from nonattainment findings, but the amendment does not itself outline the evidentiary standard beyond the existing language.
Bar to nonattainment designations where external emissions explain the exceedance
Adds subsection (e), which prevents EPA from designating an area as nonattainment for a new or revised primary or secondary NAAQS if the State shows to the Administrator’s satisfaction that the area would be in attainment but for emissions from outside the United States (including natural sources). This provision moves designation determinations toward a demonstrative, case-by-case approach and places a clear gatekeeping role with the Administrator to accept or reject state demonstrations.
Creates conditions allowing states to avoid sanctions and fees
Inserts a new statutory section that makes sanctions (under §179) and fees (under §185) inapplicable for Severe/Extreme ozone or Serious PM nonattainment areas if the State demonstrates the deficiency arose from: (1) emissions emanating from outside the nonattainment area, (2) an exceptional event (existing CAA definition), or (3) mobile-source emissions the State cannot control, provided the State has implemented all measures within its authority. It also requires renewal of the demonstration at least once every five years and explicitly preserves other statutory obligations to pursue attainment measures.
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Explore Environment in Codify Search →Who Benefits and Who Bears the Cost
Every bill creates winners and losers. Here's who stands to gain and who bears the cost.
Who Benefits
- Border and island states (e.g., Alaska, Hawaii, Washington, Maine): These states routinely receive transboundary pollution and natural plumes; the bill gives their environmental agencies a pathway to avoid nonattainment designations and federal sanctions when they can attribute exceedances to foreign or natural sources.
- State environmental agencies generally: The statute creates a formal demonstration route to avoid federal penalties and creates predictability for SIP planning and resource allocation by shifting focus to attribution analyses rather than immediate federal sanctions.
- Local regulated industries in affected states: Power plants, manufacturers, and other large stationary sources in areas that would otherwise be designated nonattainment may avoid stricter SIP requirements or permitting constraints if the State secures an exemption based on external emissions.
- States with recurring exceptional events (wildfire-prone regions): Agencies that already deal with episodic natural events gain explicit statutory recognition that those events can be treated as beyond their control for designation and sanction purposes.
Who Bears the Cost
- EPA regional offices and the Administrator: The bill increases EPA’s gatekeeping and technical-review workload because the agency must evaluate, accept, or reject complex attribution demonstrations and oversee five-year renewals.
- Downwind communities and environmental justice populations: If exemptions reduce the threat of sanctions or stricter SIP controls, local populations may experience prolonged exposure to high pollution levels from domestic sources that might otherwise have been more aggressively regulated.
- State governments (technical and budgetary burden): States must develop, defend, and periodically renew scientifically rigorous demonstrations, which requires modeling, monitoring, and possibly cross-border data exchanges — activities that carry staffing and financial costs.
- Litigants and courts: The statute is likely to spawn disputes over what suffices to "establish to the satisfaction of the Administrator," increasing litigation over attribution methods and the adequacy of state submissions.
Key Issues
The Core Tension
The central tension is between fairness and accountability: the bill seeks to prevent states from being penalized for pollution they cannot control (transboundary or natural), but in doing so it risks weakening the incentives and federal tools that drive domestic emission reductions and timely attainment of public-health standards, especially where attribution is scientifically uncertain and administratively burdensome.
The bill substitutes a demonstrative attribution pathway for certain enforcement consequences, but it leaves key evidentiary standards undefined. "Establish to the satisfaction of the Administrator" is subjective and will drive litigation and guidance development: EPA will need to define what models, monitoring density, and uncertainty bounds suffice. Attribution science for transboundary and natural plumes is complex; differences in modeling assumptions can change conclusions about whether an area "would be in attainment but for" external emissions.
That technical uncertainty risks inconsistent outcomes across EPA regions.
The statute also creates a policy trade-off between avoiding unfair penalties for states and preserving the NAAQS' protective aim. By making sanctions and fees inapplicable in specified circumstances, the bill reduces federal leverage to force faster local emission controls.
States could rely on the exemption even where some domestic sources contribute materially to exceedances unless EPA draws a hard line when evaluating demonstrations. Requiring renewals every five years adds administrative discipline but may also entrench delays while states produce new analyses.
Finally, the explicit inclusion of natural events undercuts a doctrinal distinction between anthropogenic and natural sources and raises diplomatic and data-sharing questions about how to obtain reliable foreign emissions data for attribution.
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