BOARD: BOARD: Paul C. Aughrry, lJJ Chairman Henry C. con
Edwin H. Coope r , In Vice C hairman Sreve n G. Kisner Sec rerary C. Earl Hunrer, Com mi ss ioner Promoting andprotecting the health of the public and the environment M. David Mirchell, MD Glenn A. McCall Co l eman F. Buckhouse, MD

July 8, 2011

Mr. Scott Davis , Chief Air Planning Branch US EPA Region 4 Atlanta Federal Center 61 Forsyth Street, S

.W

. Atlanta, GA 30303-8909 Re: Clarification Letter: Revision to South CarolinaAir Quality Implementation Plan SIP Package: Redesignation Demonstration and Maintenance Plan for the York County portion of the Charlotte-Gastonia-Rock ffill NC-SC Nonattainment Area Dear Mr. Davis: On June 30 and again on July 7 , 2011 , staff of the South Carolina Department of Health and Environmental Control (Department) participated in a conference call with the Environmental Protection Agency (EPA) Region 4. The discussion was held to further clarify information contained in the contingency plan portion ofthe South Carolina State Implementation Plan (SIP) submittal (June 1, 2011 ), Redesignation Demonstration and Maintenance Plan for the York County portion of the CharlotteGastonia-Rock Hill NC-SC 8-hour Ozone (Metrolina) Nonattainment Area. The following two items are offered as clarifying and supplemental information : 1

. (Section D, page 24)

- Item number 2 addresses contingency plan triggers

. The Department committed to monitor periodic emissions inventory updates and compare to projected emissions

. In the last sentence of the first paragraph, EPA was concerned that there may be an issue in defining "significantly less. " In response, for clarification, if actual emissions are greater than 10 percent of the projected emissions in the maintenance plan, the Department will investigate the differences and develop an appropriate strategy for addressing these differences

. 2

. (Section D, page 24) -Item number 4 addresses the action resulting from a trigger activation. EPA was concerned as to when South Carolina would actually determine " verification of an exceedance of the 1997 8-hour ozone NAAQS [National Ambient Air Quality Standards]" and the amount of time for selection, development, and implementation of contingency measure(s). In response, for clarification, if the quality assured/quality controlled (QA/QC) data indicates a violating design value for the 1997 8-hour ozone NAAQS , then the triggering event will be the date ofthe design value violation, and not the final QA/QC date. However, if initial monitoring data indicates a possible design value violation but later QA/QC indicates that a NAAQS violation did not occur, then a triggering event will not have occurred, and contingency measures will not need to be implemented. The Department has been and will continue proactive efforts including reviewing monitoring data and evaluating trends in an effort to identify possible violations as early as possible

. As

SOUTH CAROLINA DEPARTMENT OF HEALTH AND ENVIRONMENTAL CONTROL 2600BullStreet • Columbia,SC29201 • Phone:(803)898-3432 • www.scdhec.govClarification L etter

- RFATS Redesignation Demonstration and Maintenance Plan Jul y 08 , 2011
per the requirements established in the South Carolina Administrative Procedures Act, selection of a measure and development and implementation of necessary regulations would be expected to be completed within 24 months of activating the primary trigger

. If it is determined that a longer schedule is required to implement specific contingency measures , then, upon selection ofthe appropriate measures , the Department will notify EPA Region 4 of the proposed schedule and provide sufficient information to demonstrate that the proposed measures are a prompt correction ofthe triggering event. Should you or your staff have additional questions or comments , please contact me at 803-898-4105 or brownrj @ dhec

.sc .gov . 

# W PH

Robert J

. Brown, Jr. , Drrector Division ofAir Assessment, Innovations and Regulation Bureau ofAir Quality

ec: Lynorae Benjamin, Chief , Regulatory Development Section, EPA Region 4 Jane Spann, Ozone Coordinator, EPA Region 4 Myra Reece, Chief , BAQ , SCDHEC Renee Shealy, Assistant Bureau Chief , BAQ , SCDHEC L. Nelson Roberts , Jr., Manager, Air Quality Standards & Assessment Section, BAQ SCDHEC Maeve S

. R. Mason, Manager, Regulation and SIP Management Section, BAQ , SCDHEC Keith Overcash, Director, North Carolina Department ofEnvironment and Natural Resources , Division of Air Quality Laura Boothe, Attainment Planning Branch Supervisor, North Carolina Department of Environment and Natural Resources , Division ofAir Quality Donald W. Rodgers , Chief , Catawba Indian Nation