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Regional Haze: Rulemaking (BART and CSAPR/CAIR)

Rulemaking related to Best Available Retrofit Technology and the Cross State Air Pollution Rule/Clean Air Interstate Rule to reduce regional haze.

The Best Available Retrofit Technology (BART) and the Clean Air Interstate Rule (CAIR) were federal regulations expected to improve air quality and regional haze. The TCEQ developed state versions of the BART rule and CAIR to comply with the Federal Clean Air Act requirements. The Texas BART rule was adopted in January 2007. The Texas CAIR was adopted in July 2006. The Cross State Air Pollution Rule (CSAPR) replaced CAIR in 2011.

Best Available Retrofit Technology (BART)

The regional haze rule requires each state's SIP to require emission controls known as best available retrofit technology, or BART, for certain industrial facilities emitting air pollutants that reduce visibility by causing or contributing to regional haze. The BART Exit the TCEQ requirements of the regional haze rule apply to facilities that:

  • were built or reconstructed between August 7, 1962, and August 7, 1977;
  • have the potential to emit more than 250 tons per year of visibility-impairing pollutants; and
  • fall into one of 26 categories, including utility and industrial boilers, large industrial plants such as pulp mills, refineries, and smelters.

Some of these facilities have not been previously subject to federal requirements controlling these pollutants. States identified the facilities that have to reduce emissions under BART.

States considered a number of factors when determining which facilities were covered by BART, including:

  • the cost of the controls,
  • the impact of controls on energy usage or any environmental impacts not related to air quality,
  • the remaining useful life of the equipment to be controlled,
  • any pollution controls already in place, and
  • visibility improvement that would result from controlling the emissions. (Source: EPA Fact Sheet Exit the TCEQ)

The TCEQ’s BART Rule was adopted January 10, 2007 (30 TAC 116, Subchapter M)Exit the TCEQ

List of Potentially BART-Eligible Sources: Approximately 125 potential sources were BART-eligible. Approximately 70 sources modeled out of BART through TCEQ group modeling; these sources were required to certify that the TCEQ data was accurate. Approximately 20 potentially BART-eligible sources changed their emission rate inputs in the BART survey; some sources changed their permits and reduced their potential to emit below the threshold, and other sources shut down their older BART equipment. Approximately 35 potentially BART-eligible sources were required by the BART rule to do further modeling; none of the individual modeling reports were above the 0.5 deciview BART-eligible threshold.

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BART Analyses Submitted by Facilities

Source facilities completed BART analyses and submitted them to the TCEQ. Sources could opt to reduce emissions via permanent, enforceable permit limits to below the BART threshold and then were no longer BART-eligible. These enforceable limits were in place before the TCEQ proposed its SIP revision for regional haze.

CAMx Modeling Reports
Below are the source modeling reports. Approximately six sources used CAMx group modeling.

Note: The modeling reports are large PDF documents and can take longer to download and display. For speedier display, save the document to your computer first and then view the document from your computer.

California Puff Model (CALPUFF) Modeling Report Summaries
The TCEQ received approximately 29 CALPUFF modeling reports that are available online. Modeling report summaries are also available. Sources are listed by company name and account number as noted in the List of Potentially BART-Eligible Sources. The full modeling reports are large PDF files. Full reports and protocols are available upon request by calling the Regional Haze SIP Coordinator, or by e-mail at


From the November 9, 2006, BART informational meeting (Agenda) on modeling and engineering analysis (all links are to PDF files)

Technical Documents

Links are to PDF files, except as noted.

Draft CAMx Modeling Guidance update: Guidance for the Application of the CAMx Hybrid Photochemical Grid Model to Assess Visibility Impacts of Texas BART Sources at Class I Areas

Draft Technical Guidance Engineering Analysis—Best Available Retrofit Technology: this document outlines information and requirements for acceptable submittals of the Engineering Analysis to demonstrate Best Available Retrofit Technology

Draft BART EA-1: form and instructions for submitting BART engineering analyses

Draft Texas Modeling Data (ZIP-compressed files: Excel spreadsheet and README text document)

Draft Final Report: Screening Analysis of Potential BART-Eligible Sources in Texas

Draft Final Modeling Protocol: Screening Analysis of Potentially BART-Eligible Sources in Texas

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BART for EGUs and the Cross-State Air Pollution Rule/Clean Air Interstate Rule

On July 11, 2008, the United States Court of Appeals for the District of Columbia Circuit (the Court) vacated and later reinstated CAIR until the EPA could replace it with another rule that addressed the flaws in CAIR identified by the Court. Texas electric generating units (EGU) were only included in CAIR for the fine particulate matter (PM) requirements, not for both ozone and fine PM as were over 20 other states in the eastern half of the United States. On July 6, 2011, the EPA finalized a rule intended to replace CAIR known as Cross State Air Pollution Rule (CSAPR). CSAPR required 28 eastern states to reduce EGU emissions that contribute to ozone and fine PM pollution in other states. The rule was published in the Federal Register on August 8, 2011 and was intended to help eastern states meet Federal Clean Air Act obligations regarding interstate transport of ozone and PM. On June 7, 2012, the EPA published in the Federal Register notice that CSAPR was better than BART. To address deficiencies in CAIR-dependent regional haze SIPs, the EPA promulgated Federal Implementation Plans (FIPs) to replace reliance on CAIR with reliance on CSAPR in the regional haze SIPs of Georgia, Indiana, Iowa, Kentucky, Michigan, Missouri, Ohio, Pennsylvania, South Carolina, Tennessee, Virginia and West Virginia. On August 21, 2012, the Court vacated CSAPR and ordered the EPA to continue to administer CAIR while it works on a replacement transport rule. On November 19, 2012, the EPA’s Washington office released a memo communicating the EPA’s intent regarding the stayed CSAPR ruling, including that CAIR may be used to approve certain SIPs.

On July 28, 2015, the U.S. Court of Appeals for the D.C. Circuit found that the CSAPR 2014 SO2 and ozone season NOX budgets for Texas and certain other states were invalid because the budgets required more emission reductions than was necessary. The court remanded without vacatur to the EPA for reconsideration of the emission budgets. On November 10, 2016, the EPA published a proposed rule to remove Texas sources from the CSAPR SO2 and annual NOX trading programs. Because Texas is no longer subject to the annual NOX or SO2 programs in CSAPR, the EPA published a proposed FIP to address BART for Texas EGUs on January 4, 2017.

For more details, see the TCEQ's CSAPR website or the EPA's CSAPR website.

On March 10, 2005, the EPA issued CAIR, requiring reductions in emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) from EGUs in 28 eastern states and the District of Columbia. When fully implemented, CAIR would have reduced SO2 emissions in these states by over 70% and NOx emissions by over 60% from 2003 levels. The CAIR established an EPA-administered cap and trade program for EGUs in which states would participate as a means of meeting these requirements. For the BART rule, the EPA presented the results of an analysis showing that controls for EGUs subject to CAIR would have resulted in more visibility improvement in natural areas than BART would have provided. Therefore, states that adopted the CAIR cap and trade program for SO2 and NOx were allowed to apply CAIR controls as a substitute for controls required under BART because EPA analysis concluded that CAIR controls were better than BART for EGUs in the states subject to CAIR.

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