EPA's Region 6 Office
Serving: Arkansas, Louisiana, New Mexico, Oklahoma, Texas, and 66 Tribal Nations
Introduction to Texas Air Quality
A State Implementation Plan, commonly referred to as SIP, is an enforceable plan developed at the state level that explains how the state will comply with air quality standards according to the federal Clean Air Act. Only one State Implementation Plan exists for each state. For Texas, this Plan was initially developed in May 1972.
Rather than re-writing the entire SIP regularly, parts of the SIPs are simply revised as needed. Revisions are necessary when new federal or state requirement are enacted, when new data improves modeling techniques, when a specific area's attainment status changes, or when an area fails to reach attainment.
SIP revisions typically include an assessment of the problem and measures to fix the problem. SIP revisions start with a period of research in which data is collected and reviewed, control strategies are proposed, and the revision is drafted. The SIP revision is then sent through TCEQ rulemaking process after adoption by TCEQ's commissioners. Once adopted by the commission, it is legally binding and enforceable by state law. After adoption, the revision is submitted to the EPA for review and approval. The SIP revision is federally enforceable after it has been approved by EPA. Revisions are typically prepared for a specific area (Houston-Galveston SIP or Dallas-Ft. Worth SIP); however, sometimes SIP revisions are prepared for a particular control strategy.
The federal Clean Air Act is the legal foundation for the national air pollution control program. The Act requires each state to produce and regularly update a SIP. The Act also requires that SIPs include a description of control strategies, or measures to deal with pollution, for areas that fail to achieve national ambient air quality standards. Finally, the Act grants powers of enforcement to the EPA.
The Act grants EPA power to establish national air quality standards, to approve or reject SIPs, to replace SIPs with Federal Implementation Plans (FIPs) when deemed necessary, and to monitor achievement of goals laid out in SIPs and FIPs.