Findings of Failure to Submit State Implementation Plans Required for Attainment of the 2010 1-hour Primary Sulfur Dioxide (SO2) National Ambient Air Quality Standard (NAAQS) Fact Sheet


Findings of Failure to Submit State Implementation Plans Required for Attainment of the
2010 1-Hour Primary Sulfur Dioxide (SO2) National Ambient Air Quality Standard
(NAAQS)
FACT SHEET
ACTION
• On September 9, 2019, the U.S. Environmental Protection Agency (EPA) found that
Maryland and Michigan failed to submit complete State Implementation Plans (SIPs)
showing how areas in each state will address nonattainment of the 2010 1-Hour Primary
Sulfur Dioxide (SO2) National Ambient Air Quality Standard (NAAQS).
State
2010 1-Hour Primary SO2 NAAQS
Nonattainment Area
Maryland
Anne Arundel County and Baltimore County
Michigan
St. Clair
•	These findings of failure to submit attainment plans for the 2010 SO2 NAAQS establish a 24-
month deadline for EPA to either approve SIPs for the affected areas or finalize Federal
Implementation Plans (FIPs) that address attainment in each area.
•	This action also establishes a deadline for the implementation of two mandatory sanctions
that will begin if the states do not submit complete SIP:
1.	Eighteen months after the effective date of these findings, a 2-to-l offset ratio under the
nonattainment New Source Review (NSR) permitting program will go into effect, such
that for every unit of SO2 emissions a new or modified source will contribute to the area,
two units must be reduced.
2.	Six months after the date of offset sanctions, federal highway funding may be withheld.
•	EPA is committed to working with Maryland and Michigan to expedite the development and
submission of nonattainment area SIPs for these areas, and to review and act on their
submissions in accordance with the requirements of the Clean Air Act.
BACKGROUND
•	On June 22, 2010, EPA promulgated a new 1-hour primary SO2 NAAQS of 75 part per
billion (ppb), which is met at an ambient air quality monitoring site when the 3-year average
of the annual 99th percentile of daily maximum 1-hour average concentrations does not
exceed 75 ppb.

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• On July 12, 2016, the EPA, as part of the second round of area designations for the 2010 SO2
NAAQS, designated 4 areas of the country as nonattainment for the 1-hour primary 2010
SO2NAAQS.
• Within 18 months of the effective date of a nonattainment area designation, the Clean Air
Act requires affected states to submit a SIP demonstrating how the area will meet the
standard by the attainment date. For areas designated nonattainment for the 1-hour SO2
NAAQS on July 12, 2016, with an effective date of September 12, 2016, SIPs were due to
EPA by March 12, 2018. These plans were to show how affected areas would meet the
standard by September 12, 2021.
• SIPs must provide:
o an accurate inventory of current emissions for all sources of SO2 within the
nonattainment area;
o a New Source Review (NSR) permit program;
o an attainment demonstration using an EPA approved air quality dispersion model;
o emissions limitations and control measures to provide for attainment;
o Nonattainment for Reasonable Further Progress (RFP);
o implementation of reasonably available control measures (RACM) including reasonably
available control technology (RACT);
o contingency measures.
FOR MORE INFORMATION
• To download this action from EPA's website, go to https.V/www.epa.gov/so2-
pollution/2010-sulfur-dioxide-so2-national-ambient-air-qualitv-standards-naaqs-
implementation. The official version of this rule will be published in the Federal Register.
• Today's action and other background information are also available either electronically at
http://www.regulations.gov. the EPA's electronic public docket and comment system, or in
hardcopy at the EPA Docket Center's Public Reading Room. (Docket ID EPA-HQ-OAR-
2019-0452).
• The Public Reading Room is located in the EPA Headquarters, Room Number 3334 in the
William Jefferson Clinton West Building, located at 1301 Constitution Avenue, NW,
Washington, D.C. Hours of operation are 8:30 a.m. to 4:30 p.m. eastern standard time,
Monday through Friday, excluding federal holidays.
• Visitors are required to show photographic identification, pass through a metal detector, and
sign the EPA visitor log. All visitor materials will be processed through an x-ray machine as
well. Visitors will be provided a badge that must be visible at all times.
• For further information about this action, contact Dr. Larry D. Wallace of EPA's Office of
Air Quality Planning and Standards at (919) 541-0906 or by email at
Wallace, larry@epa.gov.

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