An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to www.epa.gov. This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Emissions During Periods of Startup, Shutdown, & Malfunction (SSM)

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

On October 9,2020, EPA issued guidance outlining 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.

Inclusion of Provisions Governing Periods of Startup, Shutdown, and Malfunctions in State Implementation Plans

Regional Updates

Iowa

On October 23, 2020, the Administrator of the EPA Region 7 Office signed a final rule to approve a State Implementation Plan revision submitted by the state of Iowa for the 2010 SO2 Muscatine, Iowa nonattainment area and to withdraw the SSM SIP Call for Iowa that was issued as part of the 2015 SSM SIP Action.

On June 16, 2020, the Administrator of the EPA Region 7 Office signed a supplemental proposed rule to approve a State Implementation Plan revision submitted by the state of Iowa for the 2010 SO2 Muscatine, Iowa nonattainment area and to withdraw the SSM SIP Call for Iowa that was issued as part of the 2015 SSM SIP Action.

North Carolina

Texas

National Rule

On May 22, 2015, EPA issued a final rule to ensure states have plans in place that require sources across the country to follow air pollution rules during times when the facility is starting up or shutting down, or when a malfunction occurs (or "SSM").

Final Rule: State Implementation Plans: Response to Petition for Rulemaking; Restatement and Update of EPA’s SSM Policy Applicable to SIPs; Findings of Substantial Inadequacy; and SIP Calls to Amend Provisions Applying to Excess Emissions During Periods of Startup, Shutdown and Malfunction (PDF)(147 pp, 928 K, About PDF)

Background

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.