The primary components of the CAA
State Implementation Plans (SIPs) – States bear the burden of implementing a plan to comply with national air quality standards (NAAQS). The NAAQS provide a maximum concentration level for certain pollutants in the air. A state has a great deal of latitude in developing a plan to implement these standards, or “state implementation plan” (SIP). Under this structure, each state must submit a SIP to the EPA that provides for implementation, maintenance, and enforcement in each air-quality control region. The EPA Administrator must approve SIPs as complete and meeting all requirements. If EPA finds a SIP inadequate to attain or maintain NAAQS, it can require revision of the plan. If the EPA finds a SIP incomplete, a state fails to make the required submissions, or if it disapproves a SIP in whole or part, it will promulgate a federal implementation plan (FIP). The EPA must promulgate the FIP within 2 years of disapproval of the SIP unless the state corrects the deficiency and the Administrator approves it.