BOARD: BOARD: 

Paul C. Aughrry, lJJ 

Chairman 

Henry C. con 

Edwin H. Coope r, In 

Vice Chairman 

Sreven G. Kisner 

Secrerary C. Earl Hunrer, Commissioner 

Promoting and protecting the health of the public and the environment 

M. David Mirchell, MD 

Glenn A. McCall 

Coleman 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 Carolina Air 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 of the 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.gov 
Clarification Letter - RF ATS Redesignation Demonstration and Maintenance Plan 

July 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 of the 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 of the triggering event. 

Should you or your staff have additional questions or comments, please contact me at 803-898-4105 or 

brownrj@dhec.sc.gov. 

WPH 

Robert J. Brown, Jr., Drrector 

Division of Air Assessment, Innovations and Regulation 

Bureau of Air 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 of Environment and Natural Resources, 

Division of Air Quality 

Laura Boothe, Attainment Planning Branch Supervisor, North Carolina Department of 

Environment and Natural Resources, Division of Air Quality 

Donald W. Rodgers, Chief, Catawba Indian Nation