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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 - September 2019

As required by the Clean Air Act, EPA is finding that Maryland and Michigan failed to submit complete State Implementation Plans for areas designated nonattainment for the 2010 1-hour primary National Ambient Air Quality Standard for sulfur dioxide (SO2). The states’ plans were due to EPA on March 12, 2018.  Once this action becomes effective, two sanctions clocks will start if the states do not submit a completed SIP.  These clocks and/or sanctions can be stopped once the states 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, highway funding may be withheld.

EPA will be required to develop a Federal Implementation Plan at the end of 24 months if the agency has not approved a complete SIP from an affected state.

EPA is committed to working with Maryland and Michigan to expedite the development and submission of their state plan revisions and to ensure continued progress toward cleaner air.

A pre-publication version of the notice and a summary fact sheet are available below.

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