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Sulfur Dioxide (SO2) Pollution

Findings of Failure to Submit State Implementation Plans Required for Attainment of the 2010 1-Hour Primary Sulfur Dioxide National Ambient Air Quality Standard - October 2020

October 8, 2020 - As required by the Clean Air Act, EPA is finding that Indiana, Louisiana, Guam, and Puerto Rico failed to submit complete State Implementation Plans (SIPs) for areas designated nonattainment for the 2010 1-hour primary National Ambient Air Quality Standard for sulfur dioxide (SO2). These plans were due to EPA on October 9, 2019.  These findings establish a 24-month deadline for EPA to either approve a SIP for the affected areas or finalize a Federal Implementation Plan for each remaining area.

Once this action becomes effective, two sanctions clocks will start if the named states and territories do not submit complete SIPs. These clocks and/or sanctions can be stopped once the states/territories make complete submissions.

  1. Eighteen months after the effective date of this finding, a 2-to-1 offset ratio under nonattainment New Source Review (NSR) permitting program will go into effect. That means for every unit of SO2 emissions a new or modified source would contribute to the area two units must be reduced before pre-construction permit would be granted. 
  2. Six months after the date of offset sanctions, federal highway funding may be withheld.

EPA is committed to working with Indiana, Louisiana, Guam, and Puerto Rico to expedite the development and submission of their state plan revisions and to ensure continued progress toward cleaner air.

Read the final rule.

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