UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION IX

The Honorable David Y. lge Governor, State ofHawaii State Capitol Executive Chambers Honolulu, Hawaii 96813 Dear Governor lge: 75 Hawthorne Street San Francisco, CA 94105-3901 

## FEB 16 2C16 OFFICE OF THE REGIONAL ADMINISTRATOR

On May 19, 2011, then-Governor Neil Abercrombie submitted air quality designation recommendations for the State ofHawaii for the 2010 revision to the primaryNational Ambient Air Quality Standard (NAAQS) for sulfur dioxide (S02). Reducing levels ofS02pollution is an important part ofthe U.S. Environmental Protection Agency's (EPA's) commitmentto a clean, healthy environment. Exposure to S02 can cause a range ofadverse health effects, including narrowing ofthe airways which can cause difficultybreathing and increased asthma symptoms. This letter is to notify you ofthe EPA's preliminary intentions regarding Hawaii's recommended designations. OnJune 3, 2010, the EPA strengthened the health-based or "primary" standard for S02 by establishing a standard for 1-hour average S02 concentrations at a level of75 parts perbillion. Within one year after a new orrevised standard is established, the Clean AirAct requires the Governor ofeach state to submit to the EPA a list ofall areas in the state, with recommendations for whether each area meets the standard. Through an interactive process, the EPA considers the recommendations and then promulgates designations for all areas across the country. On July 25, 2013, the EPA designated 29 areas 

### in 16 states as nonattainment, but did not at that time designate other areas. Pursuant to a March 2, 2015, courtordered schedule, 1the EPA must complete the remaining S02 designations by three specific deadlines: July 2, 2016, December 31, 2017, and December 31, 2020. This current round ofdesignations, to be completed byJuly 2, 2016, addresses two groups ofareas: (1) areas that have newly monitored violations ofthe 2010 S02 NAAQS based on the most recent 3 calendar years ofcertified monitored ambient air quality data, and (2) areas that contain any stationary source that had not been announced as ofMarch 2, 2015 for retirement and that, according to the EPA's AirMarkets Database, in 2012 emitted either (i) more than 16,000 tons ofS02, or (ii) more than 2,600 tons ofS02 with an annual average emission rate ofat least 0.45 pounds ofS02/mmBTU. After carefully considering Hawaii's recommendations and other available technical information, the EPA intends to designate as unclassifiable/attainment the following county: Intended Unclassifiable/ Attainment Area: Hawaii County, Hawaii

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

Printed on RecycledPaperWe acknowledge that in Hawaii's May 19, 2011 recommendation, Hawaii County is recommended to be designated as unclassifiable. However, based on all information available, including the recent exceptional events concurrences discussed below, the EPA intends to designate Hawaii County as unclassifiable/attainment. On December 17, 2015, Hawaii Department ofHealth (HDOH) submitted documentation to the EPA to demonstrate that exceedances ofthe 2010 1-hour SOz NAAQS that were recorded in 2012-2014 at the Hilo, Mountain View, Ocean View, and Pahala air monitoring stations located in Hawaii County (consisting ofthe Big Island ofHawaii) resulted from volcanic-related exceptional events, rather than due to emissions from powerplants in the vicinity ofthese monitors. OnFebruary4, 2016, the EPA concurred on these volcanic emissions exceptional events. With these concurrences, monitors in Hawaii County show no violations ofthe 2010 SOz NAAQS for calendar years 2012-2014. Because monitors in the county ofHawaii were recording violations ofthe standard prior to the recent exceptional events concurrence, the EPA is including the area in this round ofdesignations. The enclosed Technical Support Documentprovides a detailed analysis that supports our intended designation decisions. Ifyour state has additional information that the EPA should consider prior to finalizing these designations, please submit it to us byApril 19, 2016. We also will be publishing a notice in the FederalRegister announcing a 30-dayperiod for the public to provide input on the EPA's intended designation decisions. We will promulgate the designations for these areas byJuly 2, 2016. We will designate all otherpreviouslyundesignated areas in the state on a schedule consistent with the prescribed timing ofthe court order, i.e., byDecember 31 , 2017, orDecember 31, 2020. We look forward to a continued dialogue with you and your staffas we work together to complete the area designations and implement the 2010 primary SOz standard. For additional information regarding designations under the SOz standard, please visit our website at www.epa.gov/so2designations

. Should you have any questions, please do not hesitate to call me, orhave your staffcontact KerryDrake, Associate Director, Air Division, ofmy staffat (415) 947-4157 or drake.kerry@epa.gov. Sincerely,

Enclosure

cc: Nolan Hirai, Manager, Clean Air Branch, Hawaii Department ofHealth Elizabeth Adams, Acting Director, Region IX Air Division Janet G. McCabe, Acting Assistant Administrator for Air and Radiation Stephen D. Page, Director, Office ofAir QualityPlanning and Standards

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