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 1 6 2C16 OFFICE OF THE 

REGIONAL ADMINISTRATOR 

On May 19, 2011, then-Governor Neil Abercrombie submitted air quality designation recommendations 

for the State of Hawaii for the 2010 revision to the primary National Ambient Air Quality Standard 

(NAAQS) for sulfur dioxide (S02). Reducing levels ofS02 pollution is an important part ofthe U.S. 

Environmental Protection Agency's (EPA's) commitment to a clean, healthy environment. Exposure to 

S02 can cause a range of adverse health effects, including narrowing of the airways which can cause 

difficulty breathing and increased asthma symptoms. This letter is to notify you of the EPA's 

preliminary intentions regarding Hawaii's recommended designations. 

On June 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 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 the EPA a list of all 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, 1 the 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 3 

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 the EPA's 

Air Markets Database, in 2012 emitted either (i) more than 16,000 tons of S02, or (ii) more than 2,600 

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

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

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We 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 of the 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 of the Big Island of Hawaii) resulted from volcanic-related exceptional events, rather than 

due to emissions from power plants in the vicinity of these monitors. On February 4, 2016, the EPA 

concurred on these volcanic emissions exceptional events. With these concurrences, monitors in Hawaii 

County show no violations of the 2010 SOz NAAQS for calendar years 2012-2014. Because monitors in 

the county of Hawaii were recording violations of the standard prior to the recent exceptional events 

concurrence, the EPA is including the area in this round of designations. 

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

designation decisions. If your state has additional information that the 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 the 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 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, or have your staff contact Kerry Drake, 

Associate Director, Air Division, of my staff at (415) 947-4157 or drake.kerry@epa.gov. 

Sincerely, 

Enclosure 

cc: Nolan Hirai, Manager, Clean Air Branch, Hawaii Department of Health 

Elizabeth Adams, Acting Director, Region IX Air Division 

Janet G. McCabe, Acting Assistant Administrator for Air and Radiation 

Stephen D. Page, Director, Office of Air Quality Planning and Standards 

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