## United **States Department**  **of the**  **Interior OFFICE**  **OF THE**  **SECRETARY ·wash_i�_:gton,**  **DC 20240** 

**Dr. Susan**  **Hedman EPA**  **Region 5**  **Administrator U.S.**  **Environmental Protection**  **Agency 77**  **West Jackson**  **Boulevard Chicago,**  **IL 60604-3507**  **Dear Dr.**  **Hedman;** 

## AUG **1 1**  

## Z015

**On October**  **21, 2009,**  **the then Assistant Secretary**  **fot fish**  **and Wildlife**  **and Parks,**  **Mr. Thomas**  **Strickland, wrote**  **Mr. Bharat**  **Mathur, the**  **Acting Region**  **5 Administrator**  **at the**  **time, to**  **inform you**  **that the**  **Department of** **the Interior**  **(DOl) had**  **identified visibility**  **impairment at**  **Voyageurs and**  **Isle Royale**  **National Parks**  **likely attributable**  **to Xcel**  **Energy's coal-fired**  **Sherburne County**  **Generating Station**  **(Sherco) [Enclosed].**  **Since that**  **time, a**  **nun1ber of** **events have**  **led or**  **will lead**  **to significant**  **improvements in**  **visibility at**  **these Parks.**  **Most recently,**  **the Environmental Protection Agency**  **(EPA) has**  **reached a**  **settlement agreement with**  **the National**  **Parks Conservation**  **Asso ciation,**  **Friends of the**  **Bonndary Waters,**  **Voyageurs National**  **Park Association,**  **Fresh Energy,**  **the Siena Club,**  **and the**  **Northern States**  **Power Company**  **Mim1esota, d/b/a**  **Xcel Energy,**  **concerning the**  **operation of**  **and emission levels**  **at Sherco.**  **The settlement**  **agreement, which** **became effective**  **on July**  **24, 201** **5 after**  **notice to**  **tl1e United**  **States District**  **Comt for**  **the District**  **of Minnesota,**  **continues a**  **trend of**  **reducing sulfur dioxide emissions**  **at Sherco.**  **Although the**  **settlement reaches**  **a different result**  **than the**  **recommen dation**  **made in**  **our October**  **21, 200** **9 le** **tt er** **, once**  **implemented, the**  **settlement achieves**  **an outcome that addresses**  **our visibility**  **concerns at**  **Voyageurs and**  **Isle Royale National** **Parks. We**  **view the**  **settlement as**  **a reasonable**  **compromise of**  **emissions controls**  **and economic flexibility.**  **As EPA**  **proceeds with amending**  **the Minnesota** **Federal Implementation**  **Plan pursuant**  **to the**  **settlement, DOl is**  **available to** **work with**  **your agency**  **wherever we** **may be**  **of help.**  **We have**  **staff dedicated**  **to air**  **quality modeling**  **in Class**  **I areas**  **managed by**  **DOl bureaus**  **that may**  **be of**  **assistance to**  **EPA in**  **providing data**  **and analysis**  **for visibility**  **metrics now and**  **in future**  **rulemakings. We**  **are happy**  **to answers**  **questions or discuss future**  **coordination at**  **your convenience.**  **Please**

**contact Carol McCoy,**  **National Park**  **Service, at**  **(303) 969-2096**  **with inquiries.**

**cc: Sincerely,** 

**Michael J.**  **Bean Principal**  **Deputy Assistant Secretary**  **for Fish**  **and Wildlife**  **and Parks** 

**Jonathan B.**  **Jarvis, Director,**  **National Park**  **Service 1849**  **C. St.**  **NW,Washington, DC,**  **20240 David** **A Carson,**  **Depa rtment**  **of Justice**  **Environment and** **Natural Resomces**  **D i vision,**  **South Terrace**  **Suite 370,**  **999 18th** **Street Denver, CO**  **80202 Matthew**  **Marks, EPA,**  **Office of** **General Counsel**  **1200 Pennsylvania**  **Avenue, NW,**  **Washington, DC 20460** 
**Enclosure**