The Honorable Rick Snyder 

Governor of Michigan 

P.O. Box 30013 

Lansing, Michigan 48909 

Dear Governor Snyder: 

Thank you for your recommendations dated September 18, 2015 on air quality designations for the State 

of Michigan for the 2010 revision to the primary National Ambient Air Quality Standard (NAAQS) for 

sulfur dioxide (S02). Reducing levels of S02 pollution is an important part of the U.S. Environmental 

Protection Agency's commitment to a clean, healthy environment. Exposure to S02 can cause a range 

of adverse health effects, including nanowing ofthe airways which can cause difficulty breathing and 

increased asthma symptoms. This letter is to notify you ofEPA's preliminary intentions regarding your 

recommended designations. 

On June 3, 2010, EPA strengthened the health-based or "primary" standard for S02 by establishing a 

standard for 1-hour average S02 concentrations at a level of 75 parts per billion. Within one year after a 

new or revised standard is established, the Clean Air Act requires the Governor of each state to submit 

to EPA a list of all areas in the state, with recommendations for whether each area meets the standard. 

Through an interactive process, EPA considers the recommendations and then promulgates designations 

for all areas across the country. On July 25, 2013, EPA designated 29 areas in 16 states as 

nonattainment based on monitored violations, but did not at that time designate other areas. Pursuant to 

a March 2, 2015, court-ordered schedule, 1 EPA must complete the remaining S02 designations by three 

specific deadlines: July 2, 2016, December 31, 2017, and December 31, 2020. 

This current round of designations, to be completed by July 2, 2016, addresses two groups of areas: (1) 

areas that have newly monitored violations of the 2010 S02 NAAQS based on the most recent three 

calendar years of certified monitored ambient air quality data, and (2) areas that contain any stationary 

source that had not been announced as of March 2, 2015, for retirement and that according to EPA's Air 

Markets Database emitted in 2012 either (i) more than 16,000 tons ofS02 or (ii) more than 2,600 tons of 

S02 with an annual average emission rate of at least 0.45 pounds of S02/MMBTU. 

1 Sierra Club v. McCarthy, No. 3-13-cv-3953 (SI) (N.D. Cal. Mar. 2, 2015). 

Recycled/Recyclable • Printed with Vegetable Oil Based Inks on 100% Recycled Paper (100% Post·Consumer) 
Intended Unclassifiable/ Attainment Area 

Lansing County 

Marquette County 

Ottawa County 

Intended Unclassifiable Area 

Bay County* 

Monroe County* 

Intended Unclassifiable/ Attainment Area Counties 

Eaton and Ingham Counties 

Marquette County 

Ottawa County 

Intended Unclassifiable Area Counties 

Bay County 

Monroe County 

The asterisk(*) indicates a modification to the designation that you have recommended. The (p) 

indicates only a portion of the county will be designated. 

As discussed in more detail in the enclosed Technical Support Document, your state's reconunendation 

for attainment designations for Bay and Monroe Counties relies on federal consent decrees requiring the 

shutdown of relevant sources by April 15,2016. Our present intent to designate these areas as 

unclassifiable reflects the fact that the date by which these plants must be shut down has not yet passed. 

However, we anticipate that if the sources are shutdown as of Aprill5, 2016, we will subsequently be in 

a position to designate these areas as unclassifiable/attainment. 

The enclosed Technical Support Documentp provides a detailed analysis that supports our intended 

designation decisions. If your state has additional information that EPA should consider prior to 

finalizing these designations, please submit it to us by April 19, 2016. We also will be publishing a 

notice in the Federal Register announcing a 30-day period for the public to provide input on EPA's 

intended designation decisions. We will promulgate the designations for these areas by July 2, 2016. 

We will designate all other previously undesignated areas in the state on a schedule consistent with the 

prescribed timing of the court order, i.e., by December 31, 2017, or December 31, 2020. 

We look forward to a continued dialogue with you and your staff as we work together to complete the 

area designations and implement the 2010 primary S02 standard. For additional information regarding 
Robert A. Kapla~ / v 

Acting Regional Administrator 

Enclosure 

cc: Keith Creagh, Director 

Michigan Department of Environmental Quality 

Lynn Fiedler, Chief 

Air Quality Division 

Michigan Department of Environmental Quality