On November 29, 2023, the Texas Commission on Environmental Quality (TCEQ) proposed revisions to the State Implementation Plan (SIP) to align with affected areas’ ozone non-attainment classifications that were redesignated last year. The proposed SIP revisions affect Dallas-Ft. Worth (DFW), Houston-Galveston-Brazoria (HGB) and Bexar Counties. The DFW area includes Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, Tarrant, and Wise counties. The HGB area includes Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller counties. TCEQ has also proposed revisions to 30 TAC Chapter 115 and 117 to implement rules necessary to meet the federal SIP requirements.
Prior Actions
Effective November 7, 2022, DFW and HGB were reclassified by the U.S. Environmental Protection Agency (EPA) from “serious” to “severe” for the 2008 ozone eight-hour National Ambient Air Quality Standard (NAAQS). For the 2015 eight-hour ozone NAAQS DFW, HGB and Bexar counties were reclassified from “marginal” to “moderate”. A result of this action reduced major source thresholds from 50 tons per year (tpy) of volatile organic compounds (VOC) or nitrogen oxides (NOX) to 25 tpy for DFW and HGB areas. This action in turn required sources in the DFW and HGB areas with a potential-to-emit of VOC or NOx > 25 tpy to obtain a federal operating permit no later than November 7, 2023. In addition, these actions require states to develop and submit SIP revisions to EPA by November 7, 2025.
Proposed Revisions to Texas SIP
The TCEQ is proposing to revise the SIP to address attainment demonstration, which includes photochemical modeling analysis and a weight-of-evidence assessment that meets EPA modeling guidance for the DFW, HGB, and Bexar areas. A reasonably available control technology (RACT) analysis, a reasonably available control measures analysis, motor vehicle emissions budgets for 2026, and a contingency plan would also be included in this SIP revision. The SIP proposal also incorporates related revisions to 30 TAC Chapters 115 and 117. Specifics regarding Bexar county’s reasonably available control technology SIP revision proposal can be found here: Bexar County Reasonably Available Control Technology SIP Revision (texas.gov)
Proposed Revisions to 30 TAC Chapters 115 and 117
TCEQ’s Chapter 115 and Chapter 117 Executive Summaries highlight the proposed VOC and NOX rule revisions for the affected ozone nonattainment areas. Revisions would address RACT and contingency measure requirements of the 2008 ozone NAAQS. The proposed rulemaking includes emission limits, control requirements, work practice standards, operational requirements, monitoring, testing, recordkeeping and reporting requirements for affected sources, specifically for the DFW area and Bexar County. An update to compliance schedules requirement would also be included.
Lastly the proposed revisions would correct inadvertent errors made in a previously adopted rulemaking, remove obsolete language, use consistent terminology and update rule language to reflect the current Texas Register style and format. A few key revisions include:
- Revision to definition of major source of NOX emissions in the DFW area to lower the major source threshold from 50 tpy to 25 tpy, thus extending the current Chapter 117 requirements for major sources to newly designated major sources;
- Revisions to monitoring requirements for engines that use selective catalytic reduction (SCR) systems or other chemical reagents (e.g., urea or ammonia) to reduce NOX emissions and remove ammonia monitoring requirements for manufacturer-certified Tier 4 engines;
- Revision to % O2 correction for ammonia emissions: current regulations limit ammonia emissions to 10 parts per million by volume (ppmv) at 3% O2, dry. The revised SIP will allow engines to use 15% O2 corrective to accommodate for the higher excess air in the exhaust stream;
- Addition of a new Division 2 for major sources in Bexar County Ozone Nonattainment Area, that would apply to stationary gas turbines, duct burners used in turbine exhaust ducts, and gas-fires lean-burn stationary reciprocating internal combustion engines;
- Revisions to Chapter 115 to include additional VOC control requirements and correct applicable regulations for Oil and Natural Gas Industry in the DFW an HGB areas to address EPA’s 2016 Control Technology Guidelines
There will be no revisions under Chapter 115 and 117 affecting HGB 2008 ozone NAAQS nonattainment since the area had previously been reclassified as severe nonattainment and is already meeting the severe area RACT requirements. The only revisions are to monitoring requirements for diesel engines as noted above.
The anticipated publish date in the Texas Register for the proposed revisions is December 15, 2023. The public comment period is anticipated to occur between December 1, 2023 to January 16, 2024 and comments can be submitted through TCEQ’s Public Comment system. Public Hearing dates on the proposals are scheduled in Houston (Jan. 4, 2023), San Antonio (Jan. 9, 2024) and Arlington (Jan. 11, 2024). The anticipated date of adoption is April 24, 2024.
For more information or for assistance, please contact your local Trinity Texas Office at 800.229.6655. Also, stay tuned for additional details with specific changes to Chapter 115 requirements in the DFW area in our next eNews.
