General SIP Requirements
Several sections of the Clean Air Act (Act or CAA) describe the states' planning obligations to achieve healthy air quality. Section 110 of the Act requires states to submit state implementation plans (SIPs) to EPA which provide for implementation, maintenance, and enforcement of the primary and secondary National Ambient Air Quality Standards (NAAQS) established by EPA under Title I of the Act. Section 172, and other provisions in Title I, Part D, of the Act identify additional SIP requirements for areas that do not meet the NAAQS and that have been designated as nonattainment under section 107 of the Act. Section 175A of the Act describes the maintenance plan requirements for states wishing to redesignate an area from nonattainment to attainment.
Additionally, SIPs contain state air regulations that, for example, allow states to permit the construction and operation of stationary sources, establish specific requirements for categories of stationary sources, and identify open burning requirements.
Each SIP revision submitted by the state must undergo reasonable notice and public hearing at the state level, and SIPs submitted to EPA to attain or maintain the NAAQS must include enforceable emission limitations and other control measures, schedules and timetables for compliance.
EPA evaluates submitted SIPs to determine if they meet the Act's requirements. If a SIP meets the Act's requirements, EPA will approve the SIP. EPA's notice of approval is published in the Federal Register and the approval is then codified in the Code of Federal Regulations (CFR) at 40 CFR Part 52. Once EPA approves a SIP, it is enforceable by EPA and citizens in federal district court.
The designation status for an area, i.e., whether the area is designated as attainment, nonattainment or unclassifiable, is contained in 40 CFR Part 81.