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On May 25, 2016, the EPA published two proposed rules to approve the Texas Commission on Environmental Quality's (TCEQ's) proposed Clean Air Act (CAA) redesignation substitute rulemaking whereby a finding of attainment would be made for the following due to permanent and enforceable emission reductions:

  • 1-hour ozone and the 1997 8-hour ozone National Ambient Air Quality Standard (NAAQS) for the Dallas-Fort Worth (DFW) nonattainment area, and
  • 1997 8-hour ozone NAAQS for the Houston-Galveston-Brazoria (HGB) nonattainment area.
  • Approval of the redesignation substitute will result in these areas no longer being subject to any remaining applicable anti-backsliding requirements. The final approval of these proposals will result in the Nonattainment New Source Review (NNSR) thresholds and offset ratios being based solely on the classifications for the 2008 ozone NAAQS, but the current State Implementation Plan (SIP) control measures will remain in effect. If the redesignation substitutes are finalized as proposed, the NNSR major source thresholds and offset ratios will be:
  • 100 tpy and 1.1:1 for HGB as a marginal ozone nonattainment area, and
  • 100 tpy and 1.15:1 for DFW as a moderate ozone nonattainment area.

Based on information provided by the TCEQ at the 2016 Advanced Air Permitting Seminar, the EPA will be publishing the final approval of these proposals in the last quarter of 2016 for both nonattainment areas. These final approvals will contain an effective date for which sites permitted after that effective date will be able to take advantage of the higher threshold for triggering NNSR permitting. Please note as relayed by the TCEQ, any site that has an existing major source NNSR permit and Title V permit will still be subject to the permit conditions that were previously set, and will be unable to relieve itself of these conditions due to the redesignation substitute. The conditions set by the redesignation substitute will only apply to new projects as of the effective date stated in the final rule and will have no impact on previously submitted applications or permits.

Trinity will provide an update as further redesignation substitution information as made available.

If you have any questions regarding the redesignation substitutes, please contact the Dallas Office at (972) 661-8100.