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AirPermitHub

CT · EPA Region 1

Connecticut Air Permits

Connecticut DEEP issues equipment-specific New Source Review permits under RCSA § 22a-174-3a, with permit-by-rule alternatives for certain equipment (§§ 22a-174-3b, -3c, -3d) and premises-wide Title V operating permits under § 22a-174-33. Facilities can stay below Title V with emissions caps under §§ 22a-174-33a and -33b, which replaced the expired General Permit to Limit Potential to Emit. Southwest Connecticut was reclassified to severe nonattainment for the 2008 ozone standard, lowering major source thresholds for NOx and VOC there.
Verified against agency sourceLast reviewed 2026-10-25

Air permits & authorizations

  • New Source Review (NSR) permit

    Minor NSR

    Required before construction for subject sources; issued per piece of equipment with design, operating, monitoring, recordkeeping, and emission limits. Most NSR permits do not expire.

    Thresholds (summarized from source, not a quotation)

    Per DEEP FAQ: a new individual piece of equipment with potential emissions greater than 15 tpy of any individual air pollutant, or 10 tpy or more of any federal HAP, generally needs an NSR permit unless an exemption or permit-by-rule applies. Other triggers and exemptions are in RCSA § 22a-174-3a(a).

    RCSA § 22a-174-3aOfficial page

  • Permit-by-rule (equipment-specific)

    Permit by Rule

    Material limits, operating practices, and recordkeeping in lieu of NSR for external combustion, automotive refinishing, emergency engines, nonmetallic mineral processing, and surface coating.

    RCSA § 22a-174-3bOfficial page

  • Permit-by-rule (premises-wide limits)

    Permit by Rule

    Premises-wide limits in lieu of NSR, including a premises-wide coating limit.

    Thresholds (summarized from source, not a quotation)

    Per DEEP FAQ: premises-wide VOC coating limit of 1,500 gallons per calendar year (§ 22a-174-3c(b)(10)).

    RCSA § 22a-174-3cOfficial page

  • Permit-by-rule: Combined Heat and Power

    Permit by Rule

    Notification-based authorization for CHP systems.

    RCSA § 22a-174-3dOfficial page

  • Title V alternatives (emissions caps)

    State Operating

    Let a premises with potential emissions at or above Title V thresholds operate below them by capping actual emissions. Replaced the General Permit to Limit Potential to Emit (expired November 8, 2020).

    Thresholds (summarized from source, not a quotation)

    Per DEEP FAQ: actual emissions below 80% of Title V thresholds (below 100% for greenhouse gases).

    RCSA §§ 22a-174-33a, 22a-174-33bOfficial page

Major NSR (PSD & nonattainment)

  • PSD (major NSR)

    PSD

    Major source and major modification review in attainment areas, applied through the NSR application (Attachment I, DEEP-NSR-APP-216). BACT review required.

    RCSA § 22a-174-3aOfficial page

  • Nonattainment review (major NSR)

    Nonattainment NSR

    Major source and major modification review in nonattainment areas (Attachment J, DEEP-NSR-APP-215), with LAER and offsets.

    Thresholds (summarized from source, not a quotation)

    DEEP cites potential NOx or VOC above 25 tpy for facilities in towns reclassified to severe under the 2008 ozone standard (restated).

    RCSA § 22a-174-3aOfficial page

Title V operating permits

  • Title V Operating Permit

    Title V

    Premises-wide permit combining all applicable state and federal requirements. Expires no later than five years after issuance; renewal due at least 12 months before expiration.

    RCSA § 22a-174-33 (thresholds at § 22a-174-33(a)(1)(E)-(F))Official page

Oil & Gas

Connecticut has no oil and gas production. DEEP's permitting pages list no oil-and-gas-specific air program; pipeline compressor stations and fuel storage follow standard NSR/Title V rules.

    Oil & Gas industry hub

    State air regulations

    Forms

    Guidance

    Compliance

    State compliance obligations (reporting, emissions inventory, testing) are being indexed. Use the Compliance dashboard preview to see how they will be tracked.

    Sources

    Editorial note: DEEP's FAQ page was last updated January 19, 2024; regulation links go to the official CT eRegulations System.

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