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Guidance: Inclusion of provisions governing periods of Startup, Shutdown, and Malfunctions in State Implementation Plans

This guidance memorandum outlines whether and when it may be permissible for a state to include certain types of provisions governing periods of startup, shutdown, and malfunction (SSM) in state implementation plans (SIPs) developed to assure attainment and maintenance of the National Ambient Air Quality Standards (NAAQS).

This updated guidance recognizes that SIPs contain numerous planning requirements that collectively protect the NAAQS. A SIP can adequately provide for attainment and maintenance of the NAAQS, even if the SIP allows exemptions to specific emission limits for SSM events. The guidance released today also acknowledges that affirmative defense provisions for malfunction periods may be acceptable because penalties for sudden and unavoidable malfunctions caused by circumstances beyond the control of the owner or operator may not be appropriate.

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