Questions or Comments:
You are here:

Understanding General Conformity in Texas

Information about the EPA's general conformity regulation and how it affects projects in Texas.

What is General Conformity?

General conformity is a Federal Clean Air Act requirement under Section 176(c) established to ensure that actions by the federal government will not cause or contribute to violations of the National Ambient Air Quality Standards (NAAQS) and will not delay timely attainment of the NAAQS. General conformity regulations, documented in 40 Code of Federal Regulations (CFR), Part 93, Subpart BExit the TCEQ, apply in NAAQS nonattainment and maintenance areas and require that emissions from federal actions subject to general conformity requirements are consistent with the air quality goals established in the state implementation plan (SIP). General conformity requirements apply for new nonattainment areas one year after the effective date of a nonattainment designation.

Actions Subject to General Conformity

Not every federal action in a NAAQS nonattainment or maintenance area is subject to general conformity requirements. Exempt actions include those that:

  • actions subject to transportation conformity (40 CFR Part 93, Subpart AExit the TCEQ);
  • cause a small amount of emissions (de minimis levels);
  • are presumed to conform; or
  • are specifically identified in the regulations as exempt.

A federal action must undergo a determination of general conformity compliance when emissions from that action are expected to equal or exceed the de minimis emissions thresholds established in 40 CFR §93.153Exit the TCEQ.

Areas Subject to General Conformity in Texas

Affected Area NAAQS Classification/ Designation de minimis threshold (tons per year (tpy))

Collin, Dallas, Denton, Tarrant, Ellis, Johnson, Kaufman, Parker, Rockwall, and Wise Counties


Serious Nonattainment

50 tpy of either nitrogen oxides (NOX) or volatile organic compounds (VOC)

Collin County

Lead (Pb)


25 tpy Pb

El Paso County (Portion)

Carbon Monoxide (CO)


100 tpy CO

El Paso County (Portion)

Particulate Matter (PM10)

Moderate Nonattainment

100 tpy PM10

Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller Counties


Serious Nonattainment

50 tpy of either NOX or VOC

Bexar County


Marginal Nonattainment

100 tpy of either NOX or VOC

Demonstrating General Conformity

If a federal agency determines that the emissions from an action are above de minimis and the action is not otherwise exempt, then the agency must demonstrate that direct and indirect emissions from the action will conform to the SIP. In consultation with the federal agency and the United States Environmental Protection Agency (EPA), the Texas Commission on Environmental Quality is responsible for evaluating whether a general conformity demonstration is consistent with projected emissions in the most recent, EPA-approved SIP revision for the affected NAAQS nonattainment or maintenance area.

For more information on general conformity regulations and requirements, please visit the EPA’s General ConformityExit the TCEQ page.

For information concerning the TCEQ’s environmental review role under the National Environmental Policy Act (NEPA) or to submit a NEPA review request, please visit the TCEQ’s Requesting TCEQ Review under the National Environmental Policy Act page.

Contact Us

Jamie Zech
Air Quality Division, TCEQ
Phone: 512-239-3935