1

Technical Support Document for

South Carolina Regional Haze SIP Submittal

January 2012

U.S. EPA – Region 4 

Atlanta, GA
2

Technical Support Document (TSD) for 

South Carolina Regional Haze SIP Submittal

Table of Contents

I. Background

II. Summary of EPA’s Action

III. Evaluation of Regional Haze SIP Submittal

A. Identification of Areas

B. Reasonable Progress Goals (RPGs) Development

1. Calculations of Baseline Visibility Conditions

2. Calculations of Natural Visibility Conditions

3. Uniform Rate of Progress (UROP or “Glidepath”) 

for Reasonable Progress

C. Long-Term Strategy (LTS)

1. Technical Basis for Strategy

2. Identification of Sources and Factors to be 

Considered for Reasonable Progress

3. Source or Source Category Specific Analyses for 

Reasonable Progress

4. Enforceability of Reasonable Progress Measures

D. Best Available Retrofit Technology (BART) Requirements

1. Identification of all BART-Eligible Sources

2. Modeling or other Demonstrations for BART 

Exempt Sources

3. Identification of Sources Addressed by Clean Air 

Interstate Rule (CAIR)

4. Source Specific BART Determinations

5. Enforceability of BART

E. Coordination of Regional Haze and Reasonably 

Attributable Visibility Impairment (RAVI) Requirements

F. Monitoring Strategy and Other Implementation 

Requirements

G. Emission Inventory

IV. Conclusions

_____________________________________________________________________

Note: Italicized text in this document that appears under the “State Regional Haze 

Submittal” headings are excerpts from relevant portions of the South Carolina regional 

haze submittal as cited. Figure and table citations under these headings reflect the actual 

references as listed in the State‟s SIP submittal. Page numbers refer to the SIP Narrative, 

unless otherwise specified.
3

TSD for South Carolina Regional Haze SIP Submittal

I. Background

In Section 169A of the 1977 Amendments to the Clean Air Act (CAA), Congress set 

forth a program for protecting visibility in Federal Class I areas which calls for the 

“prevention of any future, and the remedying of any existing, impairment of visibility in 

mandatory Federal Class I areas which impairment results from manmade air pollution.” 

Congress adopted the visibility provisions to protect visibility in 156 Federal Class I 

areas, which include certain national parks, memorial parks, and wilderness areas over a 

certain size, and all international parks. These areas are defined at 40 CFR 81.400, and 

listed by state at 40 CFR 81.401-81.437. On December 2, 1980, EPA promulgated 

regulations to address visibility impairment that is “reasonably attributable” to a single 

source or small group of sources (45 FR 80084). These regulations represented the first 

phase in addressing visibility impairment and deferred action on regional haze that 

emanates from a variety of sources until monitoring, modeling and scientific knowledge 

about the relationships between pollutants and visibility impairment improved. 

In the 1990 Amendments to the CAA, Congress added Section 169B and called on EPA 

to issue regional haze rules. The Regional Haze Rule (RHR) that EPA promulgated on 

July 1, 1999 (64 FR 35713) revised the existing visibility regulations to integrate 

provisions addressing regional haze visibility impairment and establish a comprehensive 

visibility protection program for Federal Class I areas. States are required to submit state 

implementation plans (SIPs) to EPA that set out each state‟s plan for complying with the 

RHR, including consultation and coordination with other states and with Federal Land 

Managers (FLMs). States must submit a regional haze SIP to EPA within three years 

after the date of designation of areas under the National Ambient Air Quality Standard 

(NAAQS) for fine particulate matter (PM2.5). EPA promulgated PM2.5 designations on 

December 17, 2004, and thus, regional haze SIPs were to be submitted to EPA by 

December 17, 2007, which is also specified at 40 CFR 51.308(b).

The RHR addressed the combined visibility effects of various pollution sources over a 

wide geographic region. Consequently, all 50 states, including those without Class I 

areas, Washington, D.C., and the Virgin Islands, are required to submit regional haze 

SIPs. 40 CFR 51.300(b)(3). The US EPA designated five Regional Planning 

Organizations (RPOs) to assist with the coordination and cooperation needed to address 

the visibility issue. The RPO that makes up the southeastern portion of the contiguous 

United States is known as VISTAS (Visibility Improvement – State and Tribal 

Association of the Southeast). VISTAS members include: the Eastern Band of the 

Cherokee Indians, other Federally Recognized Tribes and Local Air Programs within the 

geographic area, and the following states: Alabama, Florida, Georgia, Kentucky, 

Mississippi, North Carolina, South Carolina, Tennessee, Virginia, and West Virginia. The 

State of South Carolina through the South Carolina Department of Health and 

Environmental Control (SC DHEC) chose to participate in VISTAS to develop the 

technical analyses needed to fulfill the requirements of the RHR.
4

Figure 1. Geographical Areas of Regional Planning Organizations 

 

 Figure 2. Class I Areas in the VISTAS Region 
5

II. Summary of Action

EPA is proposing a limited approval of a revision to the South Carolina state 

implementation plan (SIP) submitted by the State of South Carolina, through the South 

Carolina Department of Health and Environmental Control (SC DHEC), on December 

17, 2007, that addresses regional haze for the first implementation period. This revision 

addresses the requirements of the Clean Air Act (CAA or Act) and EPA‟s rules that 

require states to prevent any future and remedy any existing anthropogenic impairment of 

visibility in mandatory Class I areas (national parks and wilderness areas) caused by 

emissions of air pollutants from numerous sources located over a wide geographic area 

(also referred to as the “regional haze program”). States are required to assure reasonable 

progress toward the national goal of achieving natural visibility conditions in Class I 

areas. EPA is proposing a limited approval of this SIP revision to implement the regional 

haze requirements for South Carolina on the basis that the revision, as a whole, 

strengthens the South Carolina SIP. Additionally, EPA is proposing to rescind the 

federal regulations previously approved into the South Carolina SIP on July 12, 1985, 

and November 24, 1987, and to rely on the provisions in South Carolina‟s December 17, 

2007, SIP submittal to meet the monitoring and long-term strategy (LTS) requirements 

for reasonably attributable visibility impairment (RAVI). EPA has previously proposed a 

limited disapproval of the South Carolina regional haze SIP because of deficiencies in the 

State‟s regional haze SIP submittal arising from the remand by the U.S. Court of Appeals 

for the District of Columbia Circuit (D.C. Circuit) to EPA of the Clean Air Interstate 

Rule (CAIR). Consequently, EPA is not proposing to take action in this rulemaking to 

address the State‟s reliance on CAIR to meet certain regional haze requirements.
6

III. Evaluation of Regional Haze SIP Submittal

A. Identification of Areas 

The SIP must identify each mandatory Class I Federal area located within the State and in 

each mandatory Class I Federal area located outside the State that may be affected by 

emissions from within the State. Where a mandatory Class I Federal area is in multiple

states, a description of how the states have assigned responsibilities for the area needs to 

be included.

State Regional Haze Submittal

SC SIP Narrative, Page 16:

South Carolina has one Class I Federal area within its borders: Cape Romain. The SC

Department of Health and Environmental Control (SC DHEC) Bureau of Air Quality is 

responsible for developing the South Carolina‟s Regional Haze SIP. This SIP establishes

RPGs for visibility improvement at this Class I Federal area and determines the BART 

requirements and long-term strategy necessary to achieve those RPGs within the first 

regional haze planning period. In developing this SIP, SC DHEC has also considered 

that emission sources outside of South Carolina may affect visibility at its Class I Federal 

area, and that emission sources within South Carolina may affect visibility at Class I 

Federal areas in neighboring states.

Figure 1.4 - 1 South Carolina Class I Federal Area

Figure 3. South Carolina Class I Federal Area

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision.
7

III. Evaluation of Regional Haze SIP Submittal

B. Reasonable Progress Goals (RPGs) Development 

B.1.Calculations of Baseline Visibility Conditions: ((40 CFR 51.308(d)(2)(i))

The period for establishing baseline visibility conditions is 2000 to 2004. For each 

mandatory Class I Federal area located within the State, the State must determine the 

average degree of visibility impairment (expressed in deciviews) for the most impaired 

and least impaired days (i.e. the 20% most impaired days and 20% least impaired days)

for each of these years. Baseline conditions are the average of these annual values. For 

each mandatory Class I Federal area located within the State, the SIP needs to calculate 

the number of deciviews by which baseline conditions exceed natural visibility 

conditions for the most impaired and least impaired days.

Where onsite monitoring is not available, the baseline visibility conditions must be 

established using the most representative monitoring available for the 2000-2004 period 

in consultation with EPA.

State Regional Haze Submittal

SC SIP Narrative, Pages 21-22:

SC DHEC estimated baseline visibility conditions at Cape Romain based on sampling 

data collected at its IMPROVE monitoring site. A five-year average (2000 to 2004) was 

calculated for each value (both best and worst) in accordance with 40 CFR 51.308(d)(2) 

and the EPA Guidance for Tracking Progress Under the Regional Haze Rule. The light 

extinction and dv visibility values for these worst and best days are based on data and 

calculations included in Appendix B.4 of this SIP. Appendix B includes a demonstration 

of the appropriateness of these values for each Class I area.

Baseline Visibility Conditions – Cape Romain SC

Class I Area Average for 

20%

Worst Days

(deciviews)

Average

for 20%

Best Days

(deciviews)

Bext (Mm-1)

Average for

20% Worst Days

Bext (Mm-1)

Average for

20% Best Days

Cape Romain 26.5 5.9 147.3 42.4

Figure 4. Baseline Visibility Conditions – Cape Romain SC

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision.
8

III. Evaluation of Regional Haze SIP Submittal

B. Reasonable Progress Goals (RPGs) Development 

B.2. Calculations of Natural Visibility Conditions: ((40 CFR 51.308(d)(2)(iii))

For each mandatory Class I Federal area located within the State, natural visibility 

conditions must be calculated by estimating the degree of visibility impairment existing 

under natural conditions for the most impaired and least impaired days, based on 

available monitoring information and appropriate data analysis techniques as specified in 

EPA-454/B-03-005, Guidance for Estimating Natural Visibility Conditions Under the 

Regional Haze Program or an approved alternative technique.

State Regional Haze Submittal

SC SIP Narrative, Page 21:

Natural background visibility, as defined in Guidance for Estimating Natural Visibility 

Condition Under the Regional Haze Program, EPA-454/B-03-005, September 2003, is 

based on annual average concentrations of fine particle components. The same annual 

average natural background visibility is assumed for all Class I Federal areas in the 

eastern U.S. (separate values are estimated for the western U.S.). Natural background 

visibility for the 20 percent worst days is estimated by assuming that fine particle 

concentrations for natural background are normally distributed and that the 90th 

percentile of the annual distribution represents natural background visibility on the 20 

percent worst days.

In the 2003 guidance, the EPA also provided that states may use a “refined approach” to 

estimate the values that characterize the natural visibility conditions of the Class I areas. 

The purpose of such a refinement would be to provide more accurate estimates with 

changes to the extinction algorithm that may include the concentration values, factors to 

calculate extinction from a measured particular species and particle size, the extinction 

coefficients for certain compounds, geographical variation (by altitude) of a fixed value, 

and the addition of visibility pollutants.

In 2005, the IMPROVE Steering Committee made recommendations for a refined 

equation that modifies the terms of the original equation to account for the most recent 

data. The choice between use of the old or the new equation for calculating the visibility 

metrics for each Class I Federal area is made by the state in which the Class I Federal 

area is located.

The new IMPROVE equation accounts for the effect of particle size distribution on light 

extinction efficiency of sulfate, nitrate, and organic carbon. New terms are added to the 

equation to account for light extinction by sea salt and light absorption by gaseous 

nitrogen dioxide. Site-specific values are used for Rayleigh scattering to account for the 

site-specific effects of elevation (and temperature). Separate relative humidity 

enhancement factors are used for small size distribution sulfate or nitrate, large size 

distribution sulfate or nitrate, and sea salt. The elemental carbon (light-absorbing 
9

carbon), fine soil, and coarse mass terms do not change between the original and new 

IMPROVE equations.

The VISTAS states chose to use the new IMPROVE equation as the basis for the 

conceptual description because it takes into account the most recent review of the science 

and because it is recommended by the IMPROVE Steering Committee. For more detailed 

discussion of the two IMPROVE equations, see Appendix B.2.

Figure 5 presents estimated natural background conditions for Cape Romain. Natural 

background visibility is predicted to be between 12 and 13 dv. Appendix F, Chapter 4 

clarifies how each term was derived to predict the following estimates. EPA has defined 

a set of default Natural Conditions (EPA, 2003b) that have been updated for the new 

IMPROVE equation on the VIEWS website and are used in this section.

19B

Natural Background Conditions Cape Romain SC

Class I Area Average for 

20%

Worst Days

(deciviews)

Average

for 20%

Best Days

(deciviews)

Bext (Mm-1)

Average for

20% Worst Days

Bext (Mm-1)

Average for

20% Best Days

Cape Romain 12.1 14.3 34.2 18.1

Figure 5. Natural Background Conditions - Cape Romain SC

EPA Findings: 

EPA proposes to find that South Carolina has adequately addressed this provision and 

that the natural background conditions that were used in the reasonable progress 

assessment were developed in an acceptable manner. The State used the new IMPROVE 

equation and developed concentrations for each term of the equation consistent with the 

recommendations and default data from the IMPROVE Steering Committee. In EPA‟s 

document, “Additional Regional Haze Questions,” dated September 27, 2006 (under 

Miscellaneous #1), EPA stated that it would approve a state‟s use of the new IMPROVE 

equation for reasonable progress. That specific answer suggested that the new equation 

should be applied consistently in the development of a state‟s regional haze SIP. 

The State of South Carolina consistently applied the new IMPROVE equation in its 

regional haze analyses. Concentration data developed using chloride data was used to 

develop natural background data for reasonable progress and most of the BART 

evaluations. However, sodium ion data was used on a case-by-case basis in some BART 

evaluation modeling that used the new IMPROVE equation. 

Because chloride ions react with sulfuric and nitric acid gases in the atmosphere, the 

concentrations of sea salt, as developed using chloride data, is lower than that developed 

using sodium data, providing a conservative estimate of the contribution of sea salt to 

visibility impairment. While the use of sodium ion data is believed to provide a more 

accurate estimate of sea salt concentrations, IMPROVE has not routinely collected this 

data. SC DHEC chose to use chloride data, which IMPROVE does collect, in the 

reasonable progress assessment to be consistent with the VISTAS RPO states in their 

regional modeling to evaluate reasonable progress with respect to the glidepath. With the 
10

exception of a few facilities where the State allowed the use of the more accurate sodium 

ion data, chloride data was also used in the BART evaluation modeling. In the cases 

where the use of the sodium ion data was allowed, the State required supplementary data 

analysis using strontium data as a marker to support the use of this data. 

EPA finds the general use of the chloride data to be appropriate since it is much more 

widely available than sodium ion data. EPA also finds the use of the sodium data for 

several BART evaluations to also be appropriate since the sodium ion data is generally 

regarded to be more accurate. Finally, EPA notes that the sea salt term in the new 

IMPROVE equation contributes only a few percent of the total of the natural background 

during best day conditions and much less under worst day conditions. Hence, there is a 

negligible difference resulting from South Carolina‟s use of both chloride and sodium 

data in the reasonable progress and BART assessments.

References use in the EPA review:

1. Additional Regional Haze Questions, EPA, September 27, 2006 Revision. 

Answers to questions that PA received from various States and Regional Planning 

Organizations (RPOs) related to the submission of regional haze SIPs under the 

program described by 40 CFR 51.308. This document provides guidance to the 

State air pollution control agencies and the general public on meeting the regional 

haze SIP requirements.

2. January 18, 2007, email from Marc Pitchford, NOAA - Air Resources Laboratory,

to Brenda Johnson, EPA. Subject: “Re: December discussions.”

3. Powerpoint presentation of the: Natural Haze Levels II: Application of the New 

IMPROVE Algorithm to Natural Species Concentration Estimates. Final Report 

of the Natural Haze Levels II Committee to the RPO Monitoring/Data Analysis 

Workgroup.
11

III. Evaluation of Regional Haze SIP Submittal

B. Reasonable Progress Goals Development 

B.3. Uniform Rate of Progress (UROP or “Glidepath”) for Reasonable Progress: 

(40 CFR 51.308(d)(1) and (40 CFR 51.308(d)(1)(i)(B))

For each mandatory Class I Federal area located within the State, the State must establish 

goals (expressed in deciviews) that provide for reasonable progress towards achieving 

natural visibility conditions. For each Class I area within the State, the State must 

analyze and determine the rate of progress needed to attain natural visibility conditions 

by the year 2064 and determine the uniform rate of visibility improvement (measured in 

deciviews) that would need to be maintained during each implementation period in order 

to attain natural visibility conditions by 2064. The State must show that the reasonable 

progress goal for each mandatory Class I Federal area represents at least as much 

visibility improvement as is expected to result from implementation of other 

requirements of the CAA during the applicable planning period (40 CFR 

51.308(d)(1)(vi)). The reasonable progress goals must provide for an improvement in 

visibility for the most impaired days over the period of the implementation plan and 

ensure no degradation in visibility for the least impaired days over the same period.

State Regional Haze Submittal

SC SIP Narrative, Pages 27-28:

3.1 Glidepath For Class I Federal Area In South Carolina

The following is a glidepath for Cape Romain. Natural background visibility is predicted 

to be between 12 and 13 dv.
12

Table 8.Uniform Rate of Progress Glidepath for 20% worst days at Cape Romain SC

SC SIP Narrative, Pages 60-61:

7.2.4 Model Results for the 2018 Base G2 Inventory Compared to the Uniform Rate

of Progress Glidepath for SC Class I Federal Area

Using 2000 - 2004 IMPROVE monitoring data, the dv values for the 20 percent best days

in each year are averaged together, producing a single average dv value for the best 

days. Similarly, the dv values for the 20 percent worst days in each year are averaged 

together,producing a single average dv value for the worst days.Figure 7.2.4-1 illustrates 

the predicted visibility improvement by 2018 resulting from the Base G2 inventory that 

represents implementation of existing federal and state regulations, compared to the 

uniform rate of progress glidepath for Cape Romain. The red lines show the target 

natural condition in 2064 for the 20 percent worst days, and the incremental dv changes 

resulting from a uniform rate of progress between current and natural conditions in 

2064, for average 20 percent worst visibility days in the 2000-2004 baseline period. The 

purple lines show the improvement expected from existing and planned emission controls 

during the period of the first long term strategy. 

...

Note that for the Class I Federal area in SC, visibility is expected to improve to levels

better than the glidepath by 2018 based solely on reductions from existing and planned

emission controls from other CAA programs. 

SC SIP Narrative, Pages 95-96:
13

7.9 Post-BART Visibility Improvement Expected at Cape Romain by 2018,

Compared to the Glidepath

As discussed earlier in Chapter 7, visibility on the 20 percent worst visibility days is

expected to improve to levels better than the glidepath by 2018 based solely on

reductions from existing and planned emission controls. Figure 7.9-1 reveals the

predicted visibility (dv) in 2018 on the worst days at Cape Romain.

...

In addition to improvement in visibility on the 20 percent worst visibility days, visibility

on the 20 percent best days is also projected to improve in 2018 at Cape Romain. Figure

7.9-2 reveals the predicted visibility (dv) in 2018 on the best days at Cape Romain.

Table 9. Uniform Rate of Progress Glidepath for 20% best days at Cape Romain SC

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision. South Carolina provided sound technical documentation to support the State‟s 

RPGs (labeled “Method 1 Prediction” in Tables 8 and 9) for the best and worst days at 

Cape Romain. 
14

III. Evaluation of Regional Haze SIP Submittal

C. Long-Term Strategy 

C.1. Technical Basis for Strategy (40 CFR 51.308(d)(3)(iii))

The SIP must document the technical basis, including modeling, monitoring and 

emissions information, on which the State is relying to determine its apportionment of 

emission reduction obligations necessary for achieving reasonable progress in each 

mandatory Class I Federal area it affects. The State may meet this requirement by relying 

on technical analyses developed by the regional planning organization and approved by

all State participants.

Modeling is not used to determine reasonable progress goals and does not determine 

whether reasonable progress has been met. Modeling is one part of the reasonable 

progress analysis. The modeling results are used to compare progress made through 

emission reductions with future year visibility at Class I areas. Note that the emission 

inventory requirements under 40 CFR 51.308(d)(4)(v) are addressed in this section.

State Regional Haze Submittal

The RHR requires states to establish RPGs for visibility improvement at each affected 

Class I area covering each approximately ten-year period until 2064. The first set of 

RPGs will comprise South Carolina‟s Long Term Strategy (LTS) covering the period 

from the present until 2018. The LTS contains the following components: 

SC SIP, Appendix H, p.H-5:

1. Inventory of all controls required or expected under all federal and state regulations 

by 2009 and 2018.

2. Modeled expected visibility improvement from planned or existing (Base G) controls 

and Comparison of Base G results for 2018 to the uniform rate of progress, or 

“glidepath,” for Cape Romain. (See also EPA TSD Section III.B.3)

3. Discussion of emissions sensitivity model runs to help determine which pollutants and 

source categories are contributing the most to visibility impairment at Cape Romain 

(runs conducted by the Georgia Institute of Technology).

4. Examination of SO2 Area of Influence (AOI) projections for Cape Romain, and also 

for any surrounding states‟ Class I areas whose AOI includes South Carolina counties, to 

determine which specific sources are most likely to be impairing visibility at specific 

Class I areas.

5. Application of the four “statutory factors,” listed in 40 CFR 51.308(d)(1)(i)(A) to 

those sources identified in the previous step. (See also EPA TSD Section III.C.3)
15

6. Identify control determination (based on the results of the four factor analyses) for 

specific sources.

7. Identify of BART-eligible sources. (See also EPA TSD Section III.D.1)

8. Examine BART-exemption modeling for BART-eligible sources to include modeling 

demonstration of visibility improvement after inclusion of BART and reasonable progress 

control determinations. (See also EPA TSD Section III.D.2)

9. Determination of RPGs based on the visibility improvement expected by 2018.

SC SIP Narrative starting at page 35:

Modeling for regional haze was performed by VISTAS for the ten southeastern states, 

including South Carolina. The sections below outline the methods and inputs used by 

VISTAS for the regional modeling. Additional details are provided in Appendices C, D, 

E, F, G, I, M and O. The modeling analysis is a complex technical evaluation that begins 

by selection of the modeling system. VISTAS decided to use the following modeling 

system:

Meteorological Model: The Pennsylvania State University/National Center for 

Atmospheric Research (PSU/NCAR) Mesoscale Meteorological Model (MM5) is 

a nonhydrostatic, prognostic meteorological model routinely used for urban- and 

regional-scale photochemical, fine particulate matter, and regional haze 

regulatory modeling studies. A coarse 36-km horizontal grid domain covering the 

continental United States was used as the grid domain for MM5. 

Emissions Model: The Sparse Matrix Operator Kernel Emissions (SMOKE) 

modeling system is an emissions modeling system that generates hourly gridded 

speciated emission inputs of mobile, nonroad mobile, area, point, fire and 

biogenic emission sources for photochemical grid models.

Air Quality Model: USEPA‟s Models-3/ Community Multiscale Air Quality 

(CMAQ) modeling system is an „One-Atmosphere‟ photochemical grid model 

capable of addressing ozone, particulate matter (PM), and visibility and acid 

deposition at regional scale. For the VISTAS modeling, a coarse 36-km grid 

resolution was used for modeling the entire United States and a finer 12-km grid 

was used to model the eastern United States. The CMAQ model was run in the 

one-way nested grid mode. This allowed the larger outer domains to feed 

concentration data to the inner nested domain.

Figure 5.4.1-1 shows the MM5 horizontal domain as the outer most, blue grid with the 

CMAQ 36-km domain nested in the MM5 domain. Figure 5.4.1-2 shows the 12-km grid, 

modeling domain for the VISTAS region. 
16

Figure 5.4.1-1. The MM5 horizontal domain is the outer most, blue grid, with the 

CMAQ 36-km domain nested in the MM5 domain. 

Figure 5.4.1-2. A more detailed view of the 12-km grid over the VISTAS region.

Care was taken in the selection of the modeling system used to develop the long-term 

strategy. The VISTAS states tried to ensure that the models selected were scientifically 

appropriate for the intended application and be freely accessible to all stakeholders. 

Scientifically appropriate means that the models address important physical and 

chemical phenomena in sufficient detail, using peer-reviewed methods. Freely accessible 

means that model formulations and coding are freely available for review and that the 

models are available to stakeholders, and their consultants, for execution and 

verification at no or low cost. These criteria were used in selecting the modeling system 

are documented on pages 26-30 of the SIP Narrative.
17

EPA Modeling Guidance recommends modeling an entire year or, at a minimum, several 

days in each quarter of a year to adequately represent the range of meteorological 

conditions that contribute to elevated levels of fine particulate matter. The year 2002 was

selected by VISTAS as the modeling year for this demonstration. Meteorological inputs 

were developed for 2002 using MM5. Emission inventories were also developed for 2002 

and processed through SMOKE. These inputs were used in the air quality model to 

predict fine particle mass and visibility. The model results for 2002 were compared with 

observed meteorological and air quality data to evaluate model performance. Several 

configurations of the meteorological and air quality model were evaluated to select a 

configuration that gave the best overall performance for the VISTAS region.

Sources and Pollutants Relied on for LTS (SC SIP Narrative, Pages 67-69):

An important step toward identifying further reasonable progress measures is to identify 

the key pollutants contributing to visibility impairment at the Cape Romain Class I area. 

To understand the relative benefit of further reducing emissions from different pollutants, 

source sectors, and geographic areas, VISTAS engaged the Georgia Institute of 

Technology to perform emission sensitivity model runs using CMAQ. Emissions in 2009 

were reduced by 30 percent for each pollutant sensitivity run. The pollutant 

contributions that were evaluated were:

SO2 from EGU sources in each VISTAS state, other RPOs in the VISTAS 12 km 

grid, and Boundary Conditions from outside the 12 km domain.

SO2 from non-EGU point sources in each VISTAS state, other RPOs, and 

Boundary Conditions

NOx from ground level sources (on-road plus off-road plus area) in each VISTAS 

state and other RPOs. In the VISTAS states, these reductions were only applied 

to specific counties that were of concern for 8-hour ozone nonattainment.

NOx from point (EGU plus non-EGU) sources in each VISTAS state and other 

RPOs

NH3 from all sources in VISTAS and other RPOs

Volatile Organic Compounds from anthropogenic and biogenic sources in the 12 

km modeling domain

Primary Carbon from all ground level sources in each VISTAS state and other 

RPOs. In the VISTAS states, these reductions were only applied to specific 

counties that were of concern for PM2.5 nonattainment.

Primary Carbon from all point sources in each VISTAS state and other RPOs

Primary Carbon from all fires in each VISTAS state and other RPOs

Figure 7.4-1 shows, the greatest benefits on the 20 percent worst days for Cape Romain 

are projected to result from further reducing SO2 from EGUs. Reductions from EGUs in 

SC would have the greatest benefits; the contribution from other VISTAS states is 

relatively small. Additional, smaller benefits would come from additional SO2 emission 

reductions from non-utility, industrial point sources. While determined not to be 

necessary at this time, SC DHEC will re-examine the need for additional non-EGU 

controls during the state‟s five-year progress report.
18

Figure 7.4 - 1 CMAQ Projections of Visibility Responses on 20% Worst Days at Cape 

Romain to 30% Reductions from the 2009 Base D Inventory for Visibility-Reducing 

Pollutants in Different Source Categories and Geographic Areas

As shown in Figure 7.4-1, ammonia (NH3) is a large contributor to visibility impairment 

on the 20 percent worst days in Cape Romain. As such, some of the worst days at Cape 

Romain and at other coastal sites in VISTAS states occur in the winter when ammonium 

nitrate has a somewhat larger contribution to visibility impairment. Therefore, reducing 

ammonia emissions would be more beneficial for reducing ammonium nitrate 

contributions to visibility impairment in wintertime than further reducing NOX emissions 

from either ground or point sources.

VOCs in South Carolina originate primarily from biogenic sources (such as vegetative 

emissions) and also contribute to visibility impairment. Controlling anthropogenic 

sources of VOCs has little, if any, visibility benefit at Cape Romain. Reducing primary 

carbon from point sources, ground level sources, and fires is projected to have almost no 

visibility benefit at Cape Romain.

As Figure 7.4-1 also shows, Cape Romain experiences a high degree of impact from 

boundary conditions coming from the east. This is primarily due to atmospheric 

conditions that cause SO2 originating from the eastern coast of the U.S. to be blown out 

over the Atlantic Ocean and then re-enter the model domain. Rather than classify these 

emissions as unique to South Carolina, the model attributes these emissions as a 

boundary condition. Note that these results from emission sensitivity runs are consistent 

with the conclusions drawn from the 2000-2004 baseline monitoring data. Again, sulfate 

was found to be the dominant contributor to visibility impairment on peak summertime 

days. Wintertime ammonia is an important contributor for sites near the coast. SC DHEC 

concludes that reducing SO2 emissions from EGU and non-EGU point sources in the 

VISTAS states would have the greatest visibility benefits for Cape Romain. Contributions 

from outside the VISTAS 12-km modeling domain are particularly important to 

determining contributions to coastal Class I Federal areas like Cape Romain. These 
19

results are consistent with CMAQ model results, in that contributions from international 

emissions to visibility at VISTAS Class I Federal areas are closer to the boundaries 

Emissions Controls Modeled (SC SIP Narrative, Pages 53-60):

Significant CAA emission control programs and consent decrees are being implemented, 

or will be implemented between the baseline period and 2018. These programs and 

decrees are described in more detail below and are projected to result in substantial 

visibility improvement at Cape Romain.

Federal and State Control Requirements

Clean Air Interstate Rule (CAIR) -U CAIR will permanently cap emissions of sulfur dioxide 

(SO2) and nitrogen oxides (NOX) in the eastern U.S. When fully implemented, CAIR will 

reduce SO2 emissions in these states by over 70 percent and NOX emissions by over 60 

percent from 2003 levels. Appendix M illustrates what sources within South Carolina‟s 

AOI are subject to CAIR and those identified source‟s planned emission reductions. 

The following table indicated the EGU controls considered for South Carolina sources in 

assessing the LTS.

EGU Controls for South Carolina Used in Base G 2018 Emission Inventory 

Plant name & ID Unit NOx 2018 Controls SO2 2018 SO2 Controls

Jefferies ORISID = 3319 3

4

none

none

None

None

Wateree ORISID=3297 WAT1

WAT2

SCR

SCR

Scrubber

Scrubber

Canadys ORISID=3280 CAN1

CAN2

CAN3

None

None

None

None

None

Scrubber

Rainey ORISID=3407 CT1A

CT1B

SCR

SCR

None

None

Taken from Appendix H table on page Appendix H-13

UNOX SIP CallU. Phase I of the NOX SIP call applies to certain EGUs and large non-EGUs, 

including large industrial boilers/turbines and cement kilns. States in the VISTAS region 

affected by the NOX SIP call have developed rules for the control of NOX emissions that 

have been approved by the EPA. This rule results in a 68 percent reduction in NOX 

emissions from large stationary combustion sources by 2006. For this analysis, the 

emissions for NOX SIP call-were capped for affected sources at 2007 levels and carried 

forward the capped levels for the 2009/2018 future year inventories.

UNC Clean Smokestacks ActU. Under the act, which was enacted in 2002, coal-fired power 

plants in North Carolina must achieve a 77-percent cut in nitrogen oxide (NOX) 

emissions by 2009 and a 73-percent cut in sulfur dioxide (SO2) emissions by 2013. 

UConsent Agreements (Santee Cooper, TECO, VEPCO, Gulf Power Crist 7, and EKPC)U. 
20

• A 2004 EPA consent decree calls for Santee Cooper to install and commence operation 

of continuous emission control equipment for PM/SO2/NOX emissions; comply with 

system-wide annual PM/SO2/NOX emissions limits; agree not to buy, sell, or trade 

PM/SO2/NOX allowances allocated to Santee Cooper System as 55 a result of said 

agreement; and to comply with emission unit limits of said agreement.

• Under a settlement agreement, Tampa Electric will install permanent emissions control 

equipment to meet stringent pollution limits; implement a series of interim pollutionreduction measures to reduce emissions while the permanent controls are designed and 

installed; and retire pollution emission allowances that Tampa Electric or others could 

use/sell to others to emit additional pollution into the environment.

• Virginia Electric and Power Co. (VEPCO) agreed to eliminate 237,000 tons of sulfur 

dioxide (SO2) and nitrogen oxides (NOX) emissions each year from eight coal-fired 

electricity generating plants in Virginia and West Virginia between now and 2013.

• A 2002 agreement calls for Gulf Power to upgrade its operation to cut NOX emission 

rates by 61 percent at its Crist generating plant by 2007, with major reductions

beginning in early 2005. The Crist plant is a significant source of NOX emissions in the 

Pensacola area.

• A July 2, 2007, consent decree between the EPA and East Kentucky Power Cooperative 

(EKPC) requires the utility to reduce its NOX and SO2 emissions by 

installing/continuously operating selective catalytic reduction (SCR) technology and flue 

gas desulfurization equipment (FGD). According to the EPA, the plant‟s total emissions 

will drop from between 50 and 75 percent from 2005 levels. As with all federal consent 

decrees, EKPC is precluded from using reductions required under other programs, such 

as the Clean Air Interstate Rule.

One-hour ozone SIPs (Atlanta / Birmingham / Northern Kentucky).U The purpose of these 

respective SIPs is to grant final approval to the request for redesignation of the 1-hour 

ozone NAAQS nonattainment area to attainment. New SIPs have been submitted to the 

EPA for public comment and approval. These SIPs require NOX reductions from specific 

coal-fired power and address transportation plans in these cities.

NOx RACT in 8-hour Nonattainment Area SIPs - NC DENR applied NOX RACT to two 

facilities located in the Charlotte nonattainment area: Philip Morris USA and Norandal 

USA.

Heavy Duty Diesel (2007) Engine Standard - - A PM emissions standard for new heavyduty engines of 0.01 grams per brake-horsepower-hour (g/bhp-hr) is to take full effect for 

2007 model year diesel engines. This standard also requires reductions in NOX and nonmethane hydrocarbons (NMHC) of 0.20 g/bhp-hr and 0.14 g/ bhp-hr, respectively. These 

NOX and NMHC standards for diesel engines will be phased in together between 2007 

and 2010. Also, sulfur in diesel fuel must be lowered to enable modern pollution-control 

technology to be effective on these diesel-powered trucks and buses. The EPA will 
21

require a 97 percent reduction in the sulfur content of highway diesel fuel from its 

current level of 500 parts per million (low sulfur diesel, or LSD) to 15 parts per million 

(ultra-low sulfur diesel, or ULSD).

Tier 2 Tailpipe - U . Tier 2 is a fleet averaging program, modeled after the California LEV 

II standards. Manufacturers can produce vehicles with emissions ranging from relatively 

dirty to zero, but the mix of vehicles a manufacturer sells each year must have average 

NOX emissions below a specified value. 

Large Spark Ignition and Recreational Vehicle Rule - EPA has adopted new standards 

for emission of oxides of nitrogen (NOX), hydrocarbons (HC), and carbon monoxide 

(CO) from several groups of previously unregulated non-road engines. Included in these 

sources are the Large Industrial Spark-Ignition Engines and Recreational Vehicles. 

Spark-ignition non-road engines are those powered by gasoline, liquid propane gas, or 

compressed natural gas rated over 19 kilowatts (kW) (25 horsepower). These engines are 

used in commercial and industrial applications, including forklifts, electric generators, 

airport baggage transport vehicles, and a variety of farm and construction applications. 

Recreational Vehicles include snowmobiles, off-highway motorcycles, and all-terrainvehicles. Rules were initiated in 2004 and are fully phased in by 2012.

Non-road Diesel Rule - This rule sets standards that will dramatically reduce emissions 

by over 90 percent from non-road diesel equipment and dramatically reduce sulfur levels 

by 99 percent from current levels in non-road diesel fuel starting in 2007. This rule will 

apply to most non-road diesel fuel in 2010 and to fuel in locomotives and marine vessels 

in 2012.

Industrial Boiler/Process Heater MACT standards - The applied MACT control 

efficiencies were four percent for SO2 and 40 percent for PM10 and PM2.5. However, as of 

June 08, 2007, the Industrial Boiler/Process Heater MACT standard was vacated. A 

mandate without a stay was issued July 30, 2007. As a result, sources that were subject to 

the rule may need to file applications for permits containing MACT limits derived on a 

case-by-case basis within a time specified by the EPA or SC DHEC. 

Combustion Turbine MACT - The projection inventories do not include the NOX cobenefit effects of the MACT regulations for Gas Turbines or stationary Reciprocating 

Internal Combustion Engines, which the EPA estimates to be small compared to the 

overall inventory.

VOC 2-, 4-, 7-, and 10-year MACT Standards - Various point source MACTs and 

associated emission reductions were implemented. We did not count reductions occurring 

before 2002.

Model Performance Evaluation (SC SIP Narrative, Pages 44-52): 
22

The initial modeling effort focused on evaluating previous regional air quality modeling 

applications and testing candidate model configurations for the SMOKE emissions and 

CMAQ model for the VISTAS 36-km and 12-km modeling domains. This effort resulted 

in a report recommending the model configuration for the annual emissions and air 

quality modeling, which is included as part of the VISTAS Emissions and Air Quality 

Modeling Protocol. (See Appendix C) The evaluation of the meteorological modeling 

configuration can be found in Appendix F, with a summary of the final meteorological 

and air quality modeling configuration in the modeling protocol contained in Appendix E 

and Appendix C, respectively.

Air quality model performance for the 2002 modeling year was initially tested in 2004 

using an early version of the VISTAS emissions inventory. In keeping with the oneatmosphere objective of the CMAQ modeling platform, model performance was 

evaluated based on measured ozone, fine particles, and acid deposition in the Air Quality 

System (AQS), IMPROVE, Speciated Trends Network (STN), Southeastern Aerosol 

Research and Characterization (SEARCH), National Acid Deposition Program (NADP) 

and Clean Air Status and Trends Network (CASTNet) monitoring networks

The air quality model‟s performance was evaluated with respect to individual 

components of fine particulate matter (PM2.5), as good model performance of the 

component species will dictate good model performance of total or reconstituted fine 

particulate matter. Model performance of the total fine particulate matter and the 

resulting total light extinction was also provided as a means to discuss the overall model 

performance for the SIP. 

The soccer and bugle plots for the all of the VISTAS IMPROVE monitors are included 

here for summary purposes. The goal and criteria levels used for regional haze model 

performance were 30% and 60%, respectively, for mean fractional bias and 50% and 

75%, respectively, for mean fractional error. Plots were presented for the average 

monthly concentrations and the performance statistics for all of the most significant light 

scattering component species (Sulfate, Nitrate, and Organic Carbon) for the 20% best 

days and 20% worst days. Plots for individual IMPROVE monitors associated with the 

South Carolina Class I area are included in Appendix F.

The soccer plots of monthly concentrations (Figures. 6.2-1 and 6.2-2) show that values 

for nitrate generally fall outside of criteria performance thresholds (red box). Sulfates 

and organic carbon generally fall within goal thresholds (green box), with a couple of 

months falling just outside the goal thresholds but well within the criteria thresholds. In 

these figures, each point represents a month. Figure 6.2-3 contains separate soccer plots 

for each season. The seasonal plots emphasize poorer nitrate performance in the 

summer (does not even appear on the plots provided because performance is off scale 

with other constituents), when observed nitrate is quite low and predicted nitrate is even 

lower. When concentration is factored into performance criteria, nitrate performance 

improves with respect to mean fractional bias and mean fractional error (Figures 6.2-4 

and 6.2-5) 
23

Additionally, performance assessed at the “one atmosphere” level was also deemed 

acceptable for ozone and particulate matter at various monitoring sites (STN, FRM, 

CASTNet, etc.). Overall, VISTAS found the Base G2 modeling results to be 

representative and acceptable for use in modeling projection for ozone, particulate 

matter, and regional haze. 
24
25

South Carolina Class I Area Performance

The following section provides stacked bar charts comparing observed fine particulate 

matter composition and modeled fine particulate matter composition. The charts display 

both the 20 percent best days and the 20 percent worst days. The stacked bar chart

allows a side by side comparison of the day observed and modeled compositional and 

total light extinction. Within each bar the color codes are: 

• Yellow = light extinction due to sulfates (bextSO4)

• Red = light extinction due to nitrates (bextNO3)

• Green = light extinction due to organic carbon (bextOC)

• Black = light extinction due to elemental (bextEC)

• Brown = light extinction due to soil (bextSoil)

• Grey = light extinction due to coarse mass (bextCM)

The components are presented in the same order for both the observed (left hand bar) 

and modeled bar (right hand bar), so it easy to identify days when the prediction light 

extinction for the component differs from the observed. The total height of the bar 

provides the total reconstructed particulate matter light extinction value. A cursory view 

of the stacked bar charts reiterates that sulfates are a large contributor to light extinction 

at Cape Romain on both the 20 percent best days and the 20 percent worst days.

Comparing the 20 percent best day chart to the 20 percent worst days chart, illustrates 

that the various components of particle pollution play a more prominent role in the 20 

percent best days than with the 20 percent worst days. Also, the species make-up on the 

20 percent best days varies more widely compared to the 20 percent worst days. This 

suggests accurately modeling each species is especially important on the 20 percent best 

days.
26

With the bar chart for the 20 percent worst days, you can see model performance does 

improve across the sites. Light extinction due to sulfate prediction is better, but it still 

falls short on some days. Light extinction due to organic carbon also becomes more 

important to total light extinction. Much like the sulfate component, the organic carbon 

component accuracy has improved performance over the 20 percent best day series, 

though some days are still under predicted.

Overall, SC DHEC found model performance to fall within acceptable limits for model 

performance. SC DHEC further asserts the one atmosphere modeling performed by the 

VISTAS contractors is representative of conditions in the southeastern states and is 

applicable for use in attainment demonstrations.
27

Once model performance was deemed adequate, the current and future year emissions

were processed through the emissions model. The air quality modeling results are used 

to determine a relative reduction in future visibility impairment, which is used to 

determine reasonable progress.

More detailed discussions of the modeling protocol, quality assurance report, 

procedures, models and data used in the regional haze analysis can be found in 

Appendices C, D, E, F and G. The archival and acquisition of data and modeling input 

and output files are discussed in Appendix I. 

EPA Findings: 

In accordance with 40 CFR 51.308(d)(3), the State of South Carolina provided the 

appropriate supporting documentation for all required analyses used to determine the 

State‟s LTS. The technical analyses and modeling used to develop the glidepath and to 

support the LTS are consistent with EPA‟s RHR, and interim and final EPA Modeling 

Guidance. EPA proposes to accept the VISTAS technical modeling to support the LTS 

and determine visibility improvement for the uniform rate of progress because the 

modeling system was chosen and simulated according to EPA Modeling Guidance. EPA 

proposes to agree with the VISTAS model performance procedures and results, and that 

the CMAQ is an appropriate tool for the regional haze assessments for the South Carolina 

LTS and regional haze SIP. 

CAIR is also an element of South Carolina‟s LTS. CAIR rule revisions were approved 

into the South Carolina SIP in 2007 and 2009. See 72 FR 57209 (October 9, 2007); 74 

FR 53167 (October 16, 2009). South Carolina opted to rely on CAIR emission reduction 
28

requirements to satisfy the BART requirements for SO2 and NOX from EGUs. See 40 

CFR 51.308(e)(4). Therefore, South Carolina only required its BART-eligible EGUs to 

evaluate PM emissions for determining whether they are subject to BART, and if 

applicable, for performing a BART control assessment. Additionally, South Carolina 

concluded that no additional controls beyond CAIR are reasonable for reasonable 

progress for SO2 for its EGUs for this first implementation period. 

The RHR allows states to implement an alternative program in lieu of BART so long as 

the alternative program can be demonstrated to achieve greater reasonable progress 

toward the national visibility goal than would BART. Under regulations issued in 2005 

revising the regional haze program, EPA made just such a demonstration for CAIR. See 

70 FR 39104 (July 6, 2005). EPA‟s regulations provide that states participating in the 

CAIR cap-and trade program under 40 CFR part 96 pursuant to an EPA-approved CAIR 

SIP or which remain subject to the CAIR federal implementation plan in 40 CFR part 97 

need not require affected BART-eligible electrical generating unit (EGUs) to install, 

operate, and maintain BART for emissions of SO2 and NOx. See 40 CFR 51.308(e)(4). 

Because CAIR did not address direct emissions of PM, states were still required to 

conduct a BART analysis for PM emissions from EGUs subject to BART for that 

pollutant. Challenges to CAIR, however, resulted in the remand of the rule to EPA. See

North Carolina v. EPA, 550 F.3d 1176 (D.C. Cir. 2008). 

EPA issued a new rule in 2011 to address the interstate transport of NOx and SO2 in the 

eastern United States. See 76 FR 48208 (August 8, 2011) (“the Transport Rule,” also 

known as the Cross-State Air Pollution Rule). On December 30, 2011, EPA proposed to 

find that the trading programs in the Transport Rule would achieve greater reasonable 

progress towards the national goal than would BART in the states in which the Transport 

Rule applies. See 76 FR 82219. Based on this proposed finding, EPA also proposed to 

revise the RHR to allow states to substitute participation in the trading programs under 

the Transport Rule for source-specific BART. EPA has not yet taken final action on that 

rule. Also on December 30, 2011, the D.C. Circuit issued an order addressing the status 

of the Transport Rule and CAIR in response to motions filed by numerous parties seeking 

a stay of the Transport Rule pending judicial review. In that order, the D.C. Circuit 

stayed the Transport Rule pending the court‟s resolutions of the petitions for review of 

that rule in EME Homer Generation, L.P. v. EPA (No. 11-1302 and consolidated cases). 

The court also indicated that EPA is expected to continue to administer CAIR in the 

interim until the court rules on the petitions for review of the Transport Rule. 

In a separate action, EPA has proposed a limited disapproval of the South Carolina 

regional haze SIP because of deficiencies in the State‟s regional haze SIP submittal 

arising from the State‟s reliance on CAIR to meet certain regional haze requirements. 

See 76 FR 82219 (December 30, 2011). EPA is not proposing to take action in this

rulemaking on issues associated with South Carolina‟s reliance on CAIR in its regional 

haze SIP.

Also, on July 30, 2007, the D.C. Circuit mandated the vacatur and remand of the 

Industrial Boiler MACT Rule. Notwithstanding the vacatur of this rule, the VISTAS 
29

states, including South Carolina, decided to leave these controls in the modeling for their 

regional haze SIPs since it is believed that by 2018, EPA will have re-promulgated an 

industrial boiler MACT rule or the states will have addressed the issue through state-level 

case-by-case MACT reviews in accordance with section 112(j) of the CAA. 

EPA proposes to find this approach acceptable for the following reasons. Effective July 

30, 2007, the D.C. Circuit mandated the vacatur and remand of the Industrial Boiler 

MACT Rule.1 This MACT was vacated since it was directly affected by the vacatur and 

remand of the Commercial and Industrial Solid Waste Incinerator Definition Rule. EPA 

proposed a new Industrial Boiler MACT rule to address the vacatur on June 4, 2010, (75 

FR 32006) and issued a final rule on March 21, 2011 (76 FR 15608). The VISTAS 

modeling included emissions reductions from the vacated Industrial Boiler MACT rule, 

and South Carolina did not redo its modeling analysis when the rule was re-issued. Even 

though South Carolina‟s modeling is based on the vacated Industrial Boiler MACT 

limits, the State‟s modeling conclusions are unlikely to be affected because the expected 

reductions due to the vacated rule were relatively small compared to the State‟s total SO2, 

PM2.5, and coarse particulate matter (PM10) emissions in 2018 (i.e., 0.2 to 0.5 percent, 

depending on the pollutant, of the projected 2018 SO2, PM2.5, and PM10 inventory). 

Thus, EPA does not expect that differences between the vacated and final Industrial 

Boiler MACT emissions limits would affect the adequacy of the existing South Carolina 

regional haze SIP. If there is a need to address discrepancies between projected 

emissions reductions from the vacated Industrial Boiler MACT and the Industrial Boiler 

MACT issued March 21, 2011 (76 FR 15608), EPA expects South Carolina to do so in 

the State‟s five-year progress report. 

References used in the EPA review: 

1. EPA‟s Guidance on the Use of Models and Other Analyses for Demonstrating 

Attainment of Air Quality Goals for Ozone, PM2.5, and Regional Haze. Located at 

http://www.epa.gov/scram001/guidance/guide/final-03-pm-rh-guidance.pdf (EPA-454/B07-002), April 2007.

2. “(Draft) Guidance for Demonstrating Attainment of Air Quality Goals for PM2.5 and 

Regional Haze”, (2001), EPA, http://www.epa.gov/ttn/scram/guidance_sip.htm.

3. 2002 Base Year Emission Inventory SIP Planning: 8-hr Ozone, PM2.5 and Regional 

Haze, EPA memorandum from Lydia Wegman, EPA, to Peter Tsirigotis, EPA,

November 18, 2002.

4. Clean Air Act (CAA) §§112(j)(2), (3), (5), and (6). 

5. CAA §505 specifies procedures for notification to the Administrator and affected

states.

 

1

See NRDC v. EPA, 489 F.3d 1250 (D.C. Cir. 2007).
30

III. Evaluation of Regional Haze SIP Submittal

C. Long-Term Strategy 

C.2. Identification of Sources and Factors to be Considered for Reasonable 

Progress: (40 CFR 51.308(d)(3)(iv-v)) 

The State must identify all anthropogenic sources of visibility impairment considered by 

the State in developing its long-term strategy. The State should consider major and minor 

stationary sources, mobile sources, and area sources. The State must consider, at a 

minimum, the following factors in developing its long-term strategy: (A) emission 

reductions due to ongoing air pollution control programs, including measures to address 

reasonably attributable visibility impairment; (B) measures to mitigate the impacts of 

construction activities; (C) emissions limitations and schedules for compliance to achieve 

the reasonable progress goal; (D) source retirement and replacement schedules; (E) 

smoke management techniques for agricultural and forestry management purposes 

including plans as currently exist within the State for these purposes; measures to 

mitigate the impacts of construction activities; (F) enforceability of emission limitations 

and control measures; and the (G) anticipated net effect on visibility due to projected 

changes in point, area, and mobile source emissions over the period. 

State Regional Haze Submittal:

SC SIP Narrative, Pages 79-82:

USC DHEC Process on Reasonable Progress AssessmentU:

Step 1: Determine pollutants of concern.

VISTAS evaluated the species contribution on the 20 percent worst days and concluded

that sulfate accounted for more than 70 percent of the visibility-impairing pollution. 

VISTAS States concluded that controlling SO2 emissions was the appropriate step in

addressing the reasonable progress assessment for 2018.

Step 2: Determine which source categories should be evaluated for reasonable progress.

Since SO2 point source emissions in 2018 represent more than 95 percent of the total SO2

emissions inventory, VISTAS States concluded that the focus should be on EGU and nonEGU SO2 emissions.

Step 3: Determine if CAIR is sufficient for reasonable progress.

“In determining the emissions and visibility improvement achieved during each

implementation period, States should include all air quality improvements that will be

achieved by other programs and activities under the CAA and any State air pollution

control requirements” (64 FR 35733). In keeping with this recommendation, South

Carolina, as part of its long-term reasonable progress analysis to consider potential

sources contributing to visibility impairment, examined other CAA requirements such as

CAIR. SC DHEC evaluated the amount of SO2 reduction from EGU‟s due to CAIR. Since 

the EGUs will be reducing their SO2 emissions by approximately 78 percent through 

these programs, SC DHEC concluded that additional EGU control during this time 

period (between 2007 and 2018) was not reasonable.

Under the RHR, each “state must identify the uniform rate of progress over the 60 year

period that would be needed to attain natural background conditions by the year 2064”

(64 FR 35732). To calculate the rate of progress represented by each reasonable 
31

progress goal, South Carolina compared baseline visibility conditions to natural 

visibility conditions in its Class I Federal area and determined the uniform rate of 

visibility improvement (measured in dv) that would need to be maintained during each

implementation period in order to attain natural visibility conditions by 2064. SO2

emission reductions that are predicted by the IPM to meet the CAIR requirements are not

certain due to the current rule‟s provisions for regional emissions trading and the use of

banked Title IV allowances. However, “SIP approvability criteria [under CAIR] are

intended to provide as much certainty as possible that, whichever sources a State chooses

to control, the controls will result in the required amount of emissions reductions” (91

FR 25256). Furthermore, for EGUs subject to CAIR, the EPA evaluated a number of 

factors including the cost of compliance and the time necessary for compliance. Within 

the CAIR rule, EPA determined “that the earliest reasonable deadline for compliance 

with the final highly-cost effective control levels for reducing emissions was 2015...” (70 

FR 25197-25198). Based on this analysis, SC DHEC has determined that CAIR controls

satisfy reasonable progress for the initial planning period. These criteria along with the 

success of NOX SIP call reductions and SC DHEC‟s ongoing review of Prevention of 

Significant Deterioration/New Source Review permits serve to address this uncertainty 

and promote confidence in projected reasonable progress. Continued collaboration 

between SC DHEC and the FLM will ensure that trends in growth are addressed. SC 

DHEC also intends to re-evaluate the IPM predictions of SO2 reductions for CAIR at the 

time of the next periodic report in 2012 to ensure that the individual unit‟s reductions 

currently predicted by IPM for CAIR are in fact taking place. Based on the visibility 

improvements expected from SO2 emission reductions predicted by IPM and required by 

CAIR, SC DHEC concludes that additional SO2 control measures for South Carolina‟s 

EGUs would not achieve reasonable progress during this first assessment period 

(between baseline and 2018).

Step 4: Determine which emission units would be evaluated based on impact.

SC DHEC calculated the fractional contribution from all emission units within the SO2

AOI for Cape Romain and identified those emission units with a contribution of 0.01 or

above (or greater than or equal to one percent contribution) to the visibility impairment 

at Cape Romain. SC DHEC chose to adopt one percent as the contribution threshold 

used to consider a source for four factor analysis of reasonable further controls based on 

precedence established in other Federal programs. While SC DHEC recognizes the 

important difference between significant impact levels of human health standards and 

visibility standards, the Department contends that its approach to establishing a visibility

contribution threshold based in part on impact levels related to the precedence 

established by human health standards is appropriate and serves to further protect 

visibility.

Step 5: Evaluate the four factors.

Each emission unit identified in Step 4 above was evaluated using the statutory and

regulatory factors of: (1) cost of compliance, (2) time necessary for compliance, (3) the

energy and non-air quality environmental impacts of compliance, and (4) the remaining

useful life of the emissions unit. For the limited purpose of evaluating the cost for the

reasonable progress assessment in this first regional haze SIP, SC DHEC believes it is 

not equitable to require non-EGUs to bear a greater economic burden than EGUs for a 

given control strategy. In determining reasonable costs of controls for the EGU sector, 
32

SC DHEC determined that the cost of S02 controls (the primary contributor to visibility 

impairment in the state) beyond those required by CSA and CAIR are not reasonable. 

The capital and operating costs to implement CSA were converted to the same 15-year 

time period as the costs from AirControlNet. The unit-by-unit costs ranged from about 

$912 to $1,922 dollars per ton of SO2 removed; with an average cost per system ranging 

from $1,231 to $1,375 dollars per ton of SO2 removed (Appendix H.2.a). Therefore, 

$2,000.00 per ton was selected as the threshold for costs for non-EGU sources. This limit 

acts as an inherent barrier to non-EGUs considering additional controls. The cost of 

controls is significant--not just in terms of capital cost, but also the cost of labor needed 

to efficiently and effectively maintain the equipment. “The availability of skilled labor--

specifically, boilermakers--is an important constraint for the installation of significant 

amounts of emission controls. Boilermakers are skilled steel workers who are specially 

trained to install both NOX controls, such as SCR, and SO2 controls, such as scrubbers” 

(69 FR 4617).

SC SIP Narrative, Pages 56-57: 

The SC Forestry Commission (“SCFC”) has developed (and recently revised as of 

August 2006) the Smoke Management Guideline for Vegetative Debris Burning 

Operations, which serves to regulate vegetative debris burning for forestry, agriculture, 

and wildlife purposes in the State of SC. SC DHEC‟s Bureau of Air Quality has 

developed a state air pollution control regulation (R. 61-62.2, Prohibition of Open 

Burning) that prohibits: open burning of any/all household garbage, open burning for the 

purpose of land clearing or right of way maintenance in areas other than predominantly 

residential, and open burning of residential construction waste from building and

construction operations unless specific conditions are met.

When weighed together, these documents address all sources of fire used for land

management purposes within South Carolina and effectively minimize visibility impacts 

while recognizing the important ecological role that fires can and do play. Appendix H.1 

includes a memorandum of understanding between the SCFC and SC DHEC and 

represents the State‟s collective commitment to develop a comprehensive approach to 

establish and maintain a smoke management plan.

In addition to considering emission reductions due to ongoing air pollution programs as

required under the RHR Section 308(d)(3)(v)(A), states are also required to consider the

measures to mitigate the impacts of construction activities [40 CFR 51.308(d)(3)(v)(B)

and agricultural and forestry smoke management [40 CFR 51.308(d)(3)(v)(E)]. These

measures are discussed in more detail in Appendix H.

SC SIP Narrative, Pages 33, 59 and 60:

Table 4.1 is a summary of the 2002 baseline emission inventory for SC. The complete

inventory and discussion of the methodology is contained in Appendix D. The emissions

summaries for other VISTAS states can also be found in Appendix D.4.b.
33

56BTable 7.2.3-1 is a summary of the 2009 Base G2emission inventory. The complete

inventory and discussion of the methodology is contained in Appendix D.2 (a, b, and c).

Table 7.2.3-2 is a summary of the 2018 Base G2 emission inventory. The complete

inventory and discussion of the methodology is contained in Appendix D. 2 (a, b, and c).

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision. 

.
34

III. Evaluation of Regional Haze SIP Submittal

C. Long-Term Strategy 

C.3. Source or Source Category Specific Analyses for Reasonable Progress: (40 

CFR 51.308(d)(1)(i)(A)

For the significant sources and source categories located within the State and determined 

to be significantly impacting a mandatory Class I Federal area, the State must document 

that it considered the costs of compliance, the time necessary for compliance, the energy 

and non-air quality environmental impacts of compliance, the remaining useful life of 

any potentially affected sources, and how these factors were taken into consideration in 

establishing the reasonable progress goal.

State Regional Haze Submittal

38B

SC SIP Narrative, Pages 98-101:

Section 51.308(d)(1) of the final RHR requires that a State establish “reasonable 

progress goals” for each Class I Federal area within the state. In establishing 

reasonable progress goals, the CAA provided analytical requirements for setting these 

goals (know as the four factors) which include: the cost of compliance, the time 

necessary for compliance, the energy and non-air quality environmental impacts of 

compliance, and the remaining useful life of any existing source subject to such 

requirements. 

In developing South Carolina‟s reasonable progress goals, VISTAS, in November 2006, 

contracted with Alpine Geophysics to develop a cost control analysis that showed various 

control options for sources within an area of influence for Cape Romain and other Class 

I areas.

Since sulfate is the predominant cause of visibility impairment in the VISTAS region,

South Carolina and the other VISTAS states decided to concentrate on reduction of SO2, 

the precursor to sulfate formation, during this first planning period. As such, the cost 

control list was sorted for the SO2 emissions (Q) of each source divided by the distance 

(d) in kilometers to each class one area, or Q/d, and maximum residence time, RTmax.

All sources with a Q/d greater than or equal to five and an RTmax greater than or equal 

to 10 percent were added to the list for further consideration because it has been 

determined that these sources may contribute to visibility impairment on the 20 percent 

worst days.

Sources meeting these criteria include:

• Santee Cooper – Jefferies, South Carolina

• Santee Cooper – Cross, South Carolina

• SCE&G – Canadys, South Carolina

• International Paper – Georgetown, South Carolina

• Giant Cement, South Carolina

• Holcim Holly Hill, South Carolina

• MeadWestvaco, South Carolina

• DAK Americas, South Carolina

• International Pa Savannah Electric – McIntosh, Georgia

• International Paper – Savannah, Georgia
35

A cost threshold of $2,000.00 per ton for controls was then applied. Of the remaining 

facilities, all EGUs subject to CAIR were not considered as part of South Carolina‟s 

control strategy because CAIR makes substantial SO2 emission reductions and SO2 is the

leading pollutant that contributes to visibility impairment at Cape Romain. As Table 

7.8.2 - 3 illustrates, only two BART-eligible EGU sources in South Carolina emit any air 

pollutant which may reasonably be anticipated to cause or contribute to any impairment 

of visibility in any Class I area. The two facilities, SCE&G Williams and SCE&G 

Wateree, were unable to demonstrate less than a 0.5 dv impact at Cape Romain.

However, as stated earlier in the narrative of this appendix, these two BART-eligible

EGU sources are subject to CAIR, and South Carolina has determined that 

implementation of CAIR is equivalent to BART. As such no formal BART determinations 

were made for either of these two South Carolina sources.

SC DHEC multiplied the Q/d factors and the RTmax factors for all sources within a 

sulfate AOI for a given Class I area, then calculated a total and divided each product by 

that total to estimate the fractional contribution of each unit. Only the units with fractions 

of 0.01 or above (or greater than or equal to one percent contribution) were then 

evaluated using the four factor analysis.

Table 8.0-2 illustrates South Carolina‟s approach to establishing reasonable progress 

goals by ranking the non-EGU sources that were evaluated using the four factors. This 

list of sources was generated by evaluating each facility‟s relative cost of compliance. 

The cost of compliance (cost per ton) was calculated by dividing the total cost of the 

control strategy application by the amount of tons of SO2 reduced by the application of 

the control strategy. Under South Carolina‟s approach, facilities whose costs fall below 

the $2,000.00 threshold amount established were asked to conduct a four factor analysis. 

These facilities include:

• MeadWestvaco, SC

• International Paper, Georgetown, SC

• Giant Cement, SC

• International Paper, Savannah, GA

• Holcim: Holly Hill, SC

• DAK Americas, SC

The final four-factor analysis for the remaining non-EGU sources was performed by the 

facilities and reviewed by the Department. The reasonable progress goals established by 

SC DHEC for this first planning period take into account the controls identified as 

reasonable within the four factor analyses.

State County Plant (2002)

(2018 

)

Distance 

(km) Q/d Q/d^2

RT 

Max** RTM*(Q/d) Fraction

South Carolina Berkeley Co

SANTEE COOPER 

JEFFERIES 11,315 6,761 45.80 147.61 3.22 72.76 10740.1 0.102423

South Carolina Berkeley Co

SANTEE COOPER 

JEFFERIES 11,789 6,609 45.80 144.30 3.15 72.76 10499.27 0.100127

South Carolina Charleston Co

MEADWESTVACO 

CORPORATION INC 2,315 2,706 29.58 91.47 3.09 72.76 6655.357 0.063469

South Carolina Georgetown Co

INTERNATIONAL 

PAPER 

:GEORGETOWN 3,152 3,655 56.05 65.21 1.16 69.84 4554.266 0.043432

South Carolina Berkeley Co

SANTEE COOPER 

CROSS 0 3,835 63.26 60.62 0.96 72.76 4410.711 0.042063
36

South Carolina Colleton Co SCE&G:CANADYS 6,214 5,203 91.25 57.02 0.62 72.55 4136.801 0.039451

South Carolina Colleton Co SCE&G:CANADYS 6,585 5,144 91.12 56.45 0.62 72.55 4095.448 0.039056

South Carolina Berkeley Co

SANTEE COOPER 

CROSS 10,260 3,380 63.26 53.43 0.84 72.76 3887.567 0.037074

South Carolina Dorchester Co GIANT CEMENT CO 2,825 3,893 79.80 48.79 0.61 72.76 3549.96 0.033854

South Carolina Berkeley Co SCE&G:WILLIAMS 22,698 1,280 26.88 47.62 1.77 72.76 3464.831 0.033043

South Carolina Orangeburg Co HOLCIM:HOLLY HILL 2,957 4,074 82.56 49.35 0.60 54.08 2668.848 0.025452

South Carolina Charleston Co COGEN SOUTH 843 872 29.79 29.26 0.98 72.76 2128.958 0.020303

South Carolina Berkeley Co

ALUMAX OF SOUTH 

CAROLINA 749 957 39.06 24.50 0.63 72.76 1782.62 0.017

South Carolina Berkeley Co

ALUMAX OF SOUTH 

CAROLINA 749 957 39.17 24.43 0.62 72.76 1777.527 0.016951

South Carolina Berkeley Co

ALUMAX OF SOUTH 

CAROLINA 749 957 39.22 24.40 0.62 72.76 1775.344 0.016931

Georgia Chatham Co

INTERNATIONAL 

PAPER - SAVANNAH 

MILL 7,643 8,578 165.98 51.68 0.31 31.04 1604.147 0.015298

South Carolina Berkeley Co

ALUMAX OF SOUTH 

CAROLINA 749 957 44.04 21.73 0.49 72.76 1581.075 0.015078

South Carolina Dorchester Co

SHOWA DENKO 

CARBON 618 1,291 63.24 20.42 0.32 72.76 1485.759 0.014169

Georgia Effingham Co

SAVANNAH

ELECTRIC: 

MCINTOSH STEAM -

ELEC 7,089 7,015 155.93 44.99 0.29 31.04 1396.49 0.013318

South Carolina Orangeburg Co HOLCIM:HOLLY HILL 1,336 1,841 82.56 22.29 0.27 54.08 1205.443 0.011496

Edited from SC SIP, Appendix H.2.b:

SC SIP Narrative, Pages 104 –106:
37

MeadWestvaco: MeadWestvaco Corporation operates an unbleached paper mill in North 

Charleston, South Carolina. MeadWestvaco‟s primary source of SO2 emissions are from 

its two recovery boilers: Recovery Boiler No. 1 and Recover Boiler No. 9. The units were 

installed in 1984 and 1966 respectively. Emissions from Recovery Boiler No. 1 are 

controlled by an ESP installed in 1984. Emissions from Recovery Boiler No. 9 are also 

controlled by an ESP, installed in 1977. The No.1 and No.9 recovery boilers are

permitted to burn No.6 fuel oil, black liquor solids, spec oil and pitch as fuel. However,

on August 25, 2006, MeadWestvaco submitted a Title V permit renewal application that

included a 0.5 percent sulfur limit for fuel oil burned in the No. 9 Recovery Boiler. The

No. 1 Recovery Boiler has a SO2 PSD limit that requires the boiler to limit the amount of

high sulfur No. 6 fuel oil burned.

International Paper, Georgetown: The International Paper Georgetown, South Carolina 

Pulp and Paper Mill is located in Georgetown, South Carolina. The Mill began

operations in 1937. Primary operations at the mill include multiple fuel-fired boilers,

chemical recovery operations, wood pulping operations, bleached papermaking, and

additional operations and equipment necessary to support these operations. Unit ID 01

includes equipment that supports the Power and Recovery Operations at the Mill and

consists of: No. 1 Power Boiler, No. 2 Power Boiler, No. 1 Recovery Boiler, and No. 2

Recovery Boiler.

• No. 1 Power Boiler: The No. 1 Power Boiler is capable of burning bark, coal/synfuel, 

No. 6 fuel oil, natural gas, and propane. In addition, the boilers are capable of burning 

the following alternative fuels: wood-waste (including pulping rejects and peat), used oil, 

cleanup media materials from virgin No. 6 fuel oil spills/leaks, wastewater sludge, 

containerboard clippings/pellets, paper waste, and tire-derived fuel (TDF) and other 

rubber products. Emissions from this unit are controlled by a cyclone and electrostatic 

precipitator.

• No. 2 Power Boiler: The No. 2 Power Boiler is capable of burning bark, coal/synfuel, 

No. 6 fuel oil, natural gas, and propane. In addition, the boilers are capable of burning 

the following alternative fuels: wood-waste (including pulping rejects and peat), used oil, 

cleanup media materials from virgin No. 6 fuel oil spills/leaks, wastewater sludge, 

containerboard clippings/pellets, paper waste, and tire-derived fuel (TDF) and other 

rubber products. Emissions from this unit are controlled by a cyclone and electrostatic 

precipitator.

• No. 1 Recovery Boiler: This recovery boiler fires black liquor solids and No. 6 fuel oil, 

natural gas, and/or propane as auxiliary fuels. The No. 1 Recovery Boiler nominal 

throughput is 3.2 million pounds of black liquor solids per day, 494 MMBtu/hr from 

firing fuel oil, 24,000 scf/hr of natural gas, and 60 MMBtu/hr of propane. The unit is 

controlled by an electrostatic precipitator.

• No. 2 Recovery Boiler: This recovery boiler fires black liquor solids and No. 6 fuel oil, 

natural gas, and/or propane as auxiliary fuels. The No. 2 Recovery Boiler nominal 

throughput is 4.1 million pounds of black liquor solids per day, 494 MMBtu/hr from 

firing fuel oil, 24,000 scf/hr of natural gas, and 60 MMBtu/hr of propane. The unit is 

controlled by an electrostatic precipitator followed by a wet scrubber.

International Paper, Savannah: The Savannah Mill is located in Chatham County,

Georgia, across the Savannah River from South Carolina. It occupies a 450-acre site, 
38

and produces unbleached kraft linerboard, corrugating medium, and saturating kraft 

paper.

The Savannah Mill‟s primary source of process steam used in its pulp and papermaking

operations is the No. 13 Power Boiler unit with a maximum firing rate of up to 1,280

MMBtu/hour. The boiler is equipped with an electrostatic precipitator (ESP) for

controlling particulate emissions. The service life of the No. 13 Boiler is estimated to be

at least 40 years from installation, or until approximately 2022.

Giant Cement: Giant Cement Company owns and operates a Portland cement

manufacturing facility located in Harleyville, South Carolina. Giant‟s operations at this

facility include limestone (marl) quarrying, stone crushing, cement manufacturing,

packaging, and shipping. The facility operates one dry process cement kiln system to

produce cement clinker. The cement kiln system is equipped with fabric filters to control

PM emissions. In 2005, Giant completed the modernization of its cement manufacturing

facility at this site, which replaced four wet-process cement kilns with the newer single

dry-process kiln. In order to generate enough heat necessary to produce clinker, the

facility is permitted (Part 70 Title V/PSD Permit issued in 2003) to combust a multitude

of fuels consisting of more conventional fuels (e.g., oil, coal, natural gas) as well as 

waste derived fuels (e.g., liquid and solid hazardous waste-derived fuels). Giant‟s PSD 

permit application utilized an emission factor of 3.5 pounds of SO2 per ton of clinker 

produced, substantially lowering emissions reported from its previous wet-process kiln 

system.

Holcim: Holcim, Inc. operates a cement plant near Holly Hill, SC. This process consists

of two wet process kilns and associated process equipment that were replaced in 2003 by

a new preheater/precalciner kiln with associated process equipment. The kiln system

consists of a preheater/precalciner kiln with an in-line raw mill. The kiln progressively

heats the raw materials to over 2600 degrees Fahrenheit, producing clinker from the raw

materials. The kiln is permitted to burn coal, carbon based materials such as coke, No. 6

fuel oil, natural gas, hazardous waste derived fuel (HWDF), tire derived fuel (TDF), and

non-hazardous waste derived fuel. Emissions from the kiln are controlled by an ESP and

fabric filters.

DAK Americas: DAK operates a facility (known as the Cooper River Facility) in Moncks 

Corner, South Carolina, just north of Charleston. The Cooper River Facility (formerly 

operated by Dupont) has three main process areas consisting of: 1) a continuous 

polymerization area for polyethylene terephthalate (PET) production, 2) a PET finishing 

area to produce fiber products, and 3) a PET finishing are to produce bottle resin 

products. The Cooper River Facility‟s primary source of SO2 emissions are from its coalfired boiler (Boiler No. 2). Boiler No. 2 is a 206 MMBtu/hr bituminous coal-fired boiler. 

Boiler No. 2 is equipped with a baghouse to control PM emissions and a one percent 

sulfur limit on the coal used in Boiler No. 2 controls sulfur emissions. Compliance with 

this limit is demonstrated through calculations based on 12-month rolling sum averages 

from supplier certifications as stated in the facility‟s Part 70 Title V permit. The service 

life of Boiler No. 2 is estimated to be at least 50 years from installation, or at least 31 

additional years.

U8.1.1.3 Source Specific Control Technology Options

MeadWestvaco:

Since Recovery Boiler No. 9 currently operates using low sulfur No. 6 fuel oil,
39

MeadWestvaco conducted an abbreviated four factor analysis focused on evaluating the

feasibility of burning alternative low-sulfur fuels for Recovery Boiler No. 1. This analysis 

is summarized in Appendix N. The cost alternatives to switching from high sulfur (2.1 

percent sulfur content) No. 6 fuel oil to low sulfur No. 6 fuel oil (0.5 percent sulfur

content) for Recovery Boiler No. 1 range from $3,359.00 per ton to $7,463.00 per ton of 

SO2 removed; above the $2,000.00 cost per ton threshold. Switching to lower sulfur fuel 

oil (e.g., No. 2 Fuel oil) and natural gas would also require equipment and operating 

modifications that would further increase costs and require significant time to implement. 

Switching to lower sulfur fuels would also result in non-air quality impacts related to 

additional environmental and safety issues associated with increased truck traffic and 

additional manpower and costs for monitoring and maintaining systems.

IP Georgetown:

In conducting a four factor analysis, IP Georgetown focused its evaluation on the

feasibility of burning alternative low-sulfur fuels (the costs of which were identifies as

below the cost threshold of $2,000.00 per ton). This analysis is summarized in Appendix

N. The cost alternatives associated with switching to lower sulfur fuel range from

$6,417.00 per ton to $10,012.00 per ton of SO2 removed. In addition, the changes

required to modify the fuel tanks, piping systems, delivery systems, and burners would

also require considerable time to implement. The additional non-air quality impacts of

switching to lower sulfur fuels would also limit the IP Georgetown Mill‟s ability to

engage in burning tire-derived fuels, create additional environmental and safety issues

associated with increased truck traffic, and require secondary containment associated

with increased tank storage.

IP Savannah:

In conducting a four factor analysis, IP Savannah focused its evaluation on the feasibility 

of several SO2 control technologies, including: 1) a wet caustic packed scrubber (FGD),

2) a wet limestone spray tower (FGD), 3) a semi-dry lime spray dryer, 4) dry sorbent

injection (DSI), and 5) lower sulfur fuels. These technologies were chosen because they

have been demonstrated and are commercially available for coal-fired utility boilers. All

of the control options have been demonstrated and are considered technologically

feasible. The cost associated with each of these alternatives was calculated using the

Coal Utility Environmental Cost (CUECost) software tool and determined to be above

the $2,000.00 cost per ton threshold (with costs ranging from $2,950.00 to $34,927.00

per ton of SO2 removed). These alternatives would take from 2010 to 2012 to implement

and result in significant non-air quality impacts to include: substantial increased use of

fresh water, the generation of industrial wastewater, potentially substantial increases in

solid waste generated, additional environmental and safety issues associated with

increased truck traffic, and require additional manpower and costs for monitoring and

maintaining systems.

Giant:

In conducting a four factor analysis, Giant focused its evaluation on the feasibility of 

burning lower sulfur fuels (the costs of which were identified by the Department as below 

the cost threshold of $2,000.00 per ton). This analysis is summarized in Appendix N.

Giant determined that its costs associated with switching to lower sulfur fuel would range

from $7,801.00 per ton to $11,152.00 per ton of SO2 removed. The time required to

install fuel tanks, piping systems, and delivery systems capable of being used with lower
40

sulfur fuel oils would also require considerable time to implement. The modernized

cement kiln system (completed in 2005) provides Giant the option to operate with up to

100 percent substitution rates of conventional fuels. The additional non-air quality

impacts of switching to lower sulfur fuels would also limit the facility‟s ability to engage 

in burning liquid and solid waste-derived fuels, effectively adding to the non-air quality

impacts of finding alternate means of disposing and storing this waste.

Holcim:

In conducting a four factor analysis, Holcim also focused its evaluation on the feasibility 

of burning lower sulfur fuels (the costs of which were identified by the Department as

below the cost threshold of $2,000.00 per ton). This analysis is summarized in Appendix

N. Holcim‟s analysis determined that the cost to switch to fuel oil with a sulfur content of 

0.9 percent would cost $41,039.00 per ton of SO2 removed. Moreover, the additional nonair quality impacts of switching to lower sulfur fuels would also limit the facility‟s ability 

to engage in burning hazardous waste and tire derived fuel, thereby potentially

increasing the non-air quality impacts associated with disposing and storing this waste.

Holcim also contends that up to 95 percent of SO2 emission produced at its Holly Hill

plant can be absorbed in the process. This is because the raw materials used to produce

“kiln feed” at the Holly Hill plant consists primarily of limestone (or other forms of

calcium carbonate) and its new kiln system uses a highly alkaline feed material. 

Holcim‟s analysis indicates that the new process could result in potential SO2 reductions

of 160 tons per year.

DAK Americas:

In conducting a four factor analysis, DAK Americas focused its evaluation on the

feasibility of several SO2 control technologies, including: (1) low sulfur coal, (2) wet flue

gas desulfurization (FGD), (3) spray dryer absorber (SDA), (4) fluidized-bed combustion

(FBC) with limestone, and (5) dry sorbent injection (DSI). These technologies were

chosen because they have been demonstrated and are commercially available for 

coalfired utility boilers. Of the aforementioned control technologies all but the FBC were

deemed to be technologically feasible. Of the remaining four options, all were determined 

to be above the cost threshold of $2,000.00 per ton (see Appendix N). In addition each of 

the control technologies would take from one to three years to implement and (with the 

exception of fuel switching) result in significant non-air quality impacts to include: 

substantial increased use of fresh water, the generation of industrial wastewater, and 

potentially substantial increases in solid waste generated. The results of the four factor 

analyses (contained in Appendix N) indicate that no additional controls are reasonable at 

this time. However, further future reductions by way of additional controls have been 

discussed and will be evaluated during the next planning stage.

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision. After reviewing SC DHEC‟s methodology and analyses, EPA proposes to find 

that South Carolina‟s conclusion that no further controls are reasonable at this time 

acceptable. EPA determined that South Carolina adequately evaluated the control 

technologies available at the time of its analysis and applicable to these types of facilities 

and consistently applied its criteria for reasonable compliance costs. The State also 

included appropriate documentation in its SIP of the technical analysis it used to assess 

the need for and implementation of reasonable progress controls. Although the use of a 
41

specific threshold for assessing costs means that a state may not fully consider available 

emissions reduction measures above its threshold that would result in meaningful 

visibility improvement, EPA believes that the South Carolina SIP still ensures reasonable 

progress. In proposing to approve South Carolina‟s reasonable progress analysis, EPA is 

placing great weight on the fact that there is no indication in the SIP submittal that South 

Carolina, as a result of using a specific cost effectiveness threshold, rejected potential 

reasonable progress measures that would have had a meaningful impact on visibility in its 

Class I area. EPA notes that given the emissions reductions resulting from CAIR and the 

measures in nearby states, the visibility improvements projected for the affected Class I 

area are in excess of that needed to be on the uniform rate of progress.
42

III. Evaluation of Regional Haze SIP Submittal

C. Long-Term Strategy 

C.4. Enforceability of Reasonable Progress Measures [40CFR51.308(d)(3)]: The 

plan needs to provide enforceable emissions limitations and schedules for compliance for 

each newly adopted measure needed to achieve the reasonable progress goals. 

State Regional Haze Submittal

SC SIP Narrative, Pages 98-108:

No newly adopted source specific measures were required to achieve the reasonable 

progress goals.

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision.
43

III. Evaluation of Regional Haze SIP Submittal

D. Best Available Retrofit Technology (BART) Requirements

D.1 Identification of all BART Eligible Sources: The SIP should include a list of all 

BART-eligible sources within the State.

State Regional Haze Submittal

SC SIP Narrative, Starting at Page 82:

Section 169A of the CAA directs States to assess certain large, older emission sources for 

additional controls in order to address visibility impacts. States are directed to conduct 

BART determinations for such sources in specific source categories, and which 

contribute to visibility impairment in Class I areas. The 1999 regional haze rule includes 

the BART requirement, and directs States to include BART in their regional haze SIPs.

On July 6, 2005, USEPA published a revised final rule, including Appendix Y to 40 CFR 

Part 51, the Guidelines for BART Determinations Under the Regional Haze Rule

(hereinafter referred to as the “BART Guidelines”) that provides direction to states on 

determining which of these sources should be subject to BART, and how to determine 

BART for each source.

A BART-eligible source is one which has the potential to emit 250 tons or more of a 

visibility-impairing air pollutant, was put in place between August 7, 1962 and August 7, 

1977, and whose operations fall within one or more of 26 specifically listed source 

categories. Under the CAA, BART is required for any BART-eligible source that a State 

determines „„emits any air pollutant which may reasonably be anticipated to cause or 

contribute to any impairment of visibility in any such area.‟‟ 

For those sources subject to BART, Section 169A(g)(7) of the CAA requires that States 

must consider the following factors in making BART determinations: (1) the costs of 

compliance, (2) the energy and non-air quality environmental impacts of compliance, (3) 

any existing pollution control technology in use at the source, (4) the remaining useful 

life of the source, and (5) the degree of improvement in visibility which may reasonably 

be anticipated to result from the use of such technology. 

SC SIP Narrative, Pages 82-84:

The following is a list of facilities with BART-eligible sources in South Carolina. TRC 

Environmental Corporation was retained by VISTAS to conduct BART exemption 

modeling for several sources in South Carolina. A list of these ten facilities is included in 

Appendix H.6. Three of the ten facilities (Shaw Industries: Anderson; Solutia, Inc.; and 

Honeywell: Clemson) were later determined to be exempt form BART exemption 

modeling due to boiler size.

Appendix H.7 contains a detailed description of each BART-eligible emission unit at the 

following facilities identified as having BART-eligible sources in South Carolina.

UFACILITY NAME

ALBEMARLE, CORP.
44

BOWATER INC. PAPER/PULP

BP AMOCO CHEMICAL-COOPER RIVER PLANT

DAK AMERICA

EASTMAN CHEMICAL

INTERNATIONAL PAPER GEORGETOWN MILL

INVISTA MAY PLANT

INVISTA SARL SPARTANBURG (FORMERLY KOSA:ARTEVA)

ISG GEORGETOWN

MEADWESTVACO KRAFT MILL

MILLIKEN CHEMICAL: DEWEY PLANT

OWENS CORNING: ANDERSON

RHODIA CHARLESTON

SANTEE COOPER GRAINGER

SANTEE COOPER JEFFERIES

SANTEE COOPER WINYAH

SCE&G CANADYS

SCE&G WATEREE

SCE&G WILLIAMS

STONE CONTAINER FLORENCE

WELLMAN INC PALMETTO PLANT

These BART-eligible sources were identified using the following methodology in the

BART Guidelines2:

• One or more emission units at the facility fit within one of the 26 categories listed in the 

BART Guidelines;

• The emission unit(s) were in existence on August 7, 1977, and began operation at some 

point on or after August 7, 1962; and

• The potential emissions, considering federally enforceable permit limits, from all 

emission units identified in the previous two bullets were greater than 250 tons or more 

per year of any of these visibility-impairing pollutants: SO2, NOX, and PM10.

The BART Guidelines recommend addressing these visibility-impairing pollutants (SO2, 

NOX, and PM) and suggest that states use their best judgment in determining whether to 

address VOC and/or ammonia (NH3) emissions. As the BART Guidelines recommend, 

 

2 List of BART Source Categories. The BART requirement only applies to sources in specific categories 

listed in the Clean Air Act. These categories are: (1) Fossil-fuel fired steam electric plants of more than 250 

million British thermal units (BTU) per hour heat input, (2) Coal cleaning plants (thermal dryers), (3) Kraft 

pulp mills, (4) Portland cement plants, (5) Primary zinc smelters, (6) Iron and steel mill plants, (7) Primary 

aluminum ore reduction plants, (8) Primary copper smelters, (9) Municipal incinerators capable of charging 

more than 250 tons of refuse per day, (10) Hydrofluoric, sulfuric, and nitric acid plants, (11) Petroleum 

refineries, (12) Lime plants, (13) Phosphate rock processing plants, (14) Coke oven batteries, (15) Sulfur 

recovery plants, (16) Carbon black plants (furnace process), (17) Primary lead smelters, (18) Fuel 

conversion plants, (19) Sintering plants, (20) Secondary metal production facilities, (21) Chemical process 

plants, (22) Fossil-fuel boilers of more than 250 million BTUs per hour heat input, (23) Petroleum storage 

and transfer facilities with a capacity exceeding 300,000 barrels, (24) Taconite ore processing facilities, 

(25) Glass fiber processing plants, and (26) Charcoal production facilities.
45

South Carolina addressed SO2 and NOX, and used PM10 as an indicator for PM to 

identify BART-eligible units. As discussed in detail in Appendix H.5, VISTAS modeling 

demonstrates that neither VOCs nor NH3 form point sources in the Southeast can 

reasonably be anticipated to contribute to visibility impairment in any Class I Federal 

area. For this reason, South Carolina did not evaluate emissions of VOC and NH3 in its 

BART determinations.

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision.
46

III. Evaluation of Regional Haze SIP Submittal

D. Best Available Retrofit Technology (BART) Requirements

D.2. Modeling or Other Demonstrations for BART Exempt Sources: For each 

BART-eligible source in the State exempted from BART a demonstration, using an 

acceptable approach, that the source or group of sources does not violate the established 

threshold. The established exemption threshold for determining if a BART-eligible 

source contributes to regional haze cannot exceed 0.5 deciviews.

State Regional Haze Submittal

SC SIP Narrative, Pages 84-86:

Under the BART Guidelines, states should exempt sources from BART if it is found that

they do not contribute to visibility impairment in a Class I Federal area. In accordance

with the BART guidelines, South Carolina chose to perform source-specific analysis to

determine which sources cause or contribute to visibility impairment using the

CALPUFF model. The CALPUFF modeling protocol used for determining which

facilities are subject to BART is included in Appendix H. In accordance with the BART

Guidelines and as justified in Appendix H (Section 7.4), a contribution threshold of 0.5

dv was used to determine which sources in South Carolina were subject to BART.

Nineteen of 21 sources were able to demonstrate exemption. Facilities found to be subject 

to BART were asked to complete a BART analysis. Results of these demonstrations are 

summarized below in Table 7.8.2-1. Additional details are available in Appendix H.7. 

As approved by EPA (Appendix O.1), SC DHEC is also using the chloride derived

IMPROVE default sea salt estimate as the default value for use in the BART assessment 

for this first planning period. The Regional Haze rule, however, gives the state significant 

flexibility in making decisions concerning the BART analysis as part of the regional haze 

process.

VISTAS along with other consultants have examined the effects of sea salt and proposed 

a hierarchy of methods for sea salt estimation based on a consideration of different 

factors impinging on how technically reliable each method is for estimating sea salt in 

the atmosphere. After taking into account the various method variables as presented in 

Appendix O.3 (including chlorine depletion and blank problems) SC DHEC is convinced 

that the use of the VISTAS sodium ion data is justified and provides the most realistic, 

technically sound, yet reasonably conservative, estimate of sea salt in the Cape Romain 

Class I Federal area. This September 2002 through December 2004 sodium ion dataset 

results in a 0.77 ug/m3 sea salt estimate for the Cape Romain Class I Federal area. As a 

result, SC DHEC has chosen to accept additional information on a case-by-case basis for 

several BART facilities that have requested a more refined approach to their BART 

exemption modeling. While SC DHEC believes that the use of the sodium ion derived 

alternative sea salt estimate would be justified for any facility modeling visibility 

impairment at Cape Romain, that refinement is not necessary if a facility exempts with a 

less refined method.
47

Table 7.8.2-1 BART Modeling Results
48

* Class I Federal areas within 300 km of the source

** Screening modeling max impact

In total, 19 of SC‟s 21 BART-eligible sources were able to demonstrate that they did not

cause or contribute to visibility impairment in any Class I Federal area within 300 km of

the sources. At least 10 sources used the new IMPROVE equation in efforts to

demonstrate exemption, including: all three SCE&G facilities (Canadys, Williams, and

Wateree); all three Santee Cooper facilities (Winyah, Jefferies, and Grainger); DAK; IP

Georgetown; MeadWestvaco; and INVISTA.

65B

Determination of BART emissions to evaluate (from Appendix H, Pages H-54-56):

The guidelines required the States to include SO2, NOx, and direct particulate matter 

(PM) emissions, including both PM10 and PM2.5, in determining whether sources cause 

or contribute to visibility impairment. South Carolina and the VISTAS states used their 

best judgment and CMAQ sensitivity modeling to determine that VOC and ammonia 

emissions did not have an impact on visibility in their Class I areas and state. The results 

show that the maximum impact from eliminating all point source VOC emissions in the 

VISTAS 12-km domain is less than a 0.5 dv for all Class I areas in the VISTAS domain. 

VISTAS and the State of South Carolina conclude that VOCs from point sources are not a 

visibility impairing pollutant for BART purposes and that BART-eligible sources do not 

need to consider VOC emissions. 
49

The State of South Carolina determined through modeling that ammonia emissions from 

point sources are not anticipated to cause or contribute significantly to any impairment 

of visibility at Cape Romain with the exception of one large point source (i.e., 

Meadwestvaco, 130 tpy NH3 and 29 km to nearest Class I area). VISTAS contracted with 

Georgia Institute of Technology to perform model sensitivity runs to determine the impact 

of point source ammonia on visibility in Class I areas. Removal of the large NH3 

emission sources results in minimal impact on visibility at Class I areas in the VISTAS 

region. At their discretion, states may ask those few large sources to evaluate NH3 

impacts and potential controls for NH3. Based on annual CMAQ sensitivity analyses of 

the impacts of ammonia emissions as well as current emission rates, South Carolina 

determined that requiring to model ammonia impacts is not necessary at this time. 

CALPUFF MODELING

South Carolina chose to use source-specific analyses to determine which sources cause 

or contribute to visibility impairment using the CALPUFF model. The CALPUFF 

modeling protocol used for determining which facilities are subject to BART is included 

in Appendix H. The source-specific CALPUFF modeling protocols, which were 

supposed to be consistent with the VISTAS protocol, are also presented in Appendix H. 

SC DHEC also examined the appropriateness of the 0.5 deciview threshold for potential 

“clusters” of BART sources that might be impacting a Class I area in a cumulative 

manner, and did not find evidence that an exemption threshold less than the 0.5 deciview 

threshold should be used. Appendix H‟s main document describing reasonable progress 

has additional information in Section 5.0 regarding individual source impacts upon Class 

I areas. In accordance with the BART Guidelines, a contribution threshold of 0.5 

deciviews was used for determining which sources were subject to BART. 

Justification of 0.5 dv contribution threshold for CALPUFF BART modeling (from 

SC SIP, Appendix H, Pages H-52 and 53): 

The Regional Haze rule gives the states considerable flexibility in determining a BART 

exemption threshold, stating only that a state should not set a threshold higher than 0.5 

dv, while indicating that the state should consider the number of emission sources 

affecting the Class I Federal area, the magnitude of the sources‟ impacts, and the 

location of the sources. The number of BART sources and the different methods

available for exemption by a source makes a straightforward, apples-to-apples 

determination of a proper threshold problematic. In fact, given the state‟s limited 

resources, it would be impossible to consider every source and every situation in a 

comprehensive manner. SC DHEC decided that a stepwise, common-sense approach 

would satisfy the requirements of the rule while at the same time making the decision 

making process manageable. 

For the eight facilities impacting the Wolf Island Class I Federal area, SC DHEC 

concluded that the EPA suggested contribution threshold of 0.5 dv was appropriate in 

this situation based on a qualitative analysis of these facilities and their predicted 

visibility impacts. None of the eight facilities in question are in close proximity to Wolf 
50

Island, with the closest being just over 200 km away. Considering results of the visibility 

impacts modeling conducted, with four of the facilities reporting a 12 km screening 

(maximum) impact well below 0.5 dv and the other four reporting 4 km refined modeling 

impacts (98th percentile) below 0.3 dv, SC DHEC agrees with the state of Georgia that a 

0.5 dv threshold is appropriate for the Wolf Island Class I Federal area and a lower 

threshold was not warranted. 

For the fourteen facilities impacting the Cape Romain Class I Federal area, a more 

detailed analysis was performed. Of the fourteen facilities, two (SCE&G Williams and 

Wateree) performed a four-factor analysis and did not exempt. Of the remaining twelve 

facilities, only six (MeadWestvaco, DAK Americas, Santee Cooper Jeffries, Santee 

Cooper Winyah, International Paper Georgetown, and ISG Georgetown) were in close 

proximity to Cape Romain. For these six facilities, SC DHEC performed an analysis of 

the overlap in modeling impacts at Cape Romain. For this analysis, SC DHEC compiled 

the 8th highest impacts for each of the modeled years (2001, 2002, and 2003) to see what 

kind of overlap there was predicted on these days. It is important to note that, for this 

modeling, maximum predicted 24-hour emission rates were used. In actual operation, it 

is highly unlikely that each facility would be operating such that the maximum 24-hr 

emissions occurred at the same time. Thus, it is very likely that the actual combined 

impact at the class I area would be less than the sum of combined impacts from these 

facilities. Nevertheless, these 8th highest modeling days resulted in a total of 132 

modeled days. Of the 132 days, there were only a total of 12 days were two or more 

facilities overlapped (five days in 2001, four in 2002, and three in 2003) and only one 

day over the three years where three facilities overlapped. Thus, the overall impact from 

these facilities is relatively spread out, with very little overlap and certainly much fewer 

days of overlap than the 100 days used by EPA in the BART rule. In addition, a 0.5 dv 

threshold is consistent with the 0.5 dv threshold that all of the other VISTAS states intend 

to adopt for the Class I Federal areas in their states. In view of all this, a 0.5 dv 

threshold is appropriate and a lower threshold is not warranted. 

As a result, SC DHEC concluded that the EPA-suggested contribution threshold of 0.5 dv 

was appropriate in this situation since there are a limited number of out of state sources 

that impact Cape Romain. 

Use of the New IMPROVE Algorithm and Sea Salt (from SC SIP, Appendix H, Pages 

H-62 to H-64, and SC SIP Narrative, Page 86):

Appendix H:

During the regional haze SIP development process, the IMPROVE Steering Committee 

made recommendations for a new IMPROVE equation. Among other things, the new 

equation includes components that take into account the effects of sea salt and site 

specific Rayleigh scattering with the new IMPROVE equation to determine background 

concentrations at the Class I areas. These terms are important components to 

appropriately consider for South Carolina‟s coastal and several other facilities. 

Additional discussion of the new IMPROVE equation can be found in Appendix O.
51

VISTAS contracted Dr. Ivar Tombach to develop a post processor to allow CALPOST 

outputs to be used with the new IMPROVE equation. SC DHEC submitted to U.S. EPA 

Region 4, a request for approval to use the new IMPROVE equation and postprocessor 

developed by Dr. Tombach in BART modeling. A discussion of the rationale for use of the 

new IMPROVE equation follows. The new IMPROVE postprocessor and instructions are 

included in the request to EPA for approval of its use in Attachment O. 

Rationale for Need for Use of New IMPROVE Equation. The new IMPROVE equation is 

a much better representation of the effects of particulate matter on light extinction than 

the old equation and takes into account the latest scientific understanding of several 

parameters.

1. The new algorithm overcomes biases of the old algorithm on the haziest days and the 

clearest days as demonstrated by comparing the measured light extinction from 

nephelometers at Class I areas to light extinction calculated using each of the equations.

2. The new algorithm recognizes spatial and temporal variation in light extinction as size 

distribution of the aerosol changes by increasing extinction efficiency as sulfate, nitrate 

and organics concentrations increase.

3. The new algorithm incorporates a term to reflect the contribution of fine sea salt and 

its hygroscopic growth with increasing relative humidity recognizing research findings 

showing that fine sea salt can be an important contributor to light extinction in coastal 

areas.

4. The new algorithm reflects research finding that the mass concentration of particulate 

organic matter in rural areas is greater than represented by the old equation.

5. The new algorithm includes a NO2 term to represent times when light absorption by 

NO2 is a meaningful contributor to light extinction.

6. The new algorithm incorporates site-specific Rayleigh scattering values to better 

represent sites close to sea level or with very hot or cold climates.

With this combination of revisions to the IMPROVE equation, the resulting 

apportionment of extinction to various components is more accurate on the haziest and 

clearest days. This is important for the development of emission control strategies since 

the benefits of control of concentrations of each species will be represented more 

correctly with the new algorithm. 

A majority of South Carolina‟s BART eligible sources are located in coastal areas. The 

ability to appropriately represent the contribution of sea salt for these sources is 

important in determining their contribution to haze and evaluating the benefit of potential 

control strategies. U.S. EPA Region 4, the National Park Service, and the US Fish & 

Wildlife Service determined that adding site-specific data to account for the impact of sea 
52

salt and Rayleigh scattering to the old IMPROVE equation is not appropriate, but rather 

the entire new IMPROVE equation should be used. The spreadsheet developed by Dr. 

Tombach to implement the entire new IMPROVE equation for use with CALPUFF 

contains a modification of CALPOST that calculates the light extinction from the 

CALPUFF output. In their review of the spreadsheet and supporting documentation, EPA 

Region 4 staff commented that the VISTAS methodology contained in the spreadsheet 

developed by Dr. Tombach appropriately implements the features of the new IMPROVE 

equation, with the exception of the nitrogen dioxide term. EPA Region 4 further stated 

that with the addition of their recommendation for addressing the NO2 term, the VISTAS 

methodology to incorporate the new IMPROVE equation is acceptable on a case-by-case 

basis upon consultation with the EPA Regional Office.

South Carolina‟s request and approval to use the new IMPROVE equation for BART 

purposes are found in Attachment O.

From SC SIP Narrative, Page 86:

Sea Salt Term for New IMPROVE equation

7.8.2 Determination of Sources Subject to BART in South Carolina -- ...As approved 

by EPA (Appendix O.1), SC DHEC is also using the chloride derived IMPROVE default 

sea salt estimate as the default value for use in the BART assessment for this first 

planning period. The Regional Haze rule, however, gives the state significant flexibility 

in making decisions concerning the BART analysis as part of the regional haze process.

VISTAS along with other consultants have examined the effects of sea salt and proposed 

a hierarchy of methods for sea salt estimation based on a consideration of different 

factors impinging on how technically reliable each method is for estimating sea salt in 

the atmosphere. After taking into account the various method variables as presented in 

Appendix O.3 (including chlorine depletion and blank problems) SC DHEC is convinced 

that the use of the VISTAS sodium ion data is justified and provides the most realistic, 

technically sound, yet reasonably conservative, estimate of sea salt in the Cape Romain 

Class I Federal area. This September 2002 through December 2004 sodium ion dataset 

results in a 0.77 ug/m3 sea salt estimate for the Cape Romain Class I Federal area. As a 

result, SC DHEC has chosen to accept additional information on a case-by-case basis for 

several BART facilities that have requested a more refined approach to their BART 

exemption modeling. While SC DHEC believes that the use of the sodium ion derived 

alternative sea salt estimate would be justified for any facility modeling visibility 

impairment at Cape Romain, that refinement is not necessary if a facility exempts with a 

less refined method. 

Table 7.8.2-2 presents the facilities who requested an alternative to the default sea salt 

estimation. Note that some facilities presented data calculated with sea salt estimated by 

elemental sodium and that data is included for those facilities.

Table 7.8.2 - 2 New IMPROVE Sea Salt Estimation Methods & BART Visibility
53

Impacts

Data Access – EPA Note: Due to the size of data and modeling files that constitute the 

BART modeling developed by the sources, the archival and access of this data is made 

available to the public upon request and is discussed in Appendix I.

EPA Findings: EPA proposes to find that the State has adequately identified the BARTeligible sources and those sources subject to BART controls. EPA believes that the State

successfully developed and provided the technical analyses to support the BART 

assessment provision for the non-CAIR sources. South Carolina opted to have CAIR 

satisfy BART for SO2 and NOx for affected CAIR EGUs, as allowed under the Regional 

Haze regulations. As explained in Section III.C.1–EPA Findings, the State‟s 

demonstration regarding CAIR and reasonable progress for EGUs, and other provisions 

in this SIP revision, are based on CAIR and thus, the Agency proposes to issue a limited 

approval of the State‟s regional haze SIP revision. In a separate action, EPA has 

proposed a limited disapproval of the South Carolina regional haze SIP because of 

deficiencies in the State‟s regional haze SIP submittal arising from the State‟s reliance on 

CAIR to meet certain regional haze requirements. See 76 FR 82219 (December 30, 

2011). EPA is not proposing to take action in this rulemaking on issues associated with 

South Carolina‟s reliance on CAIR in its regional haze SIP. 

CALPUFF MODELING

EPA proposes to find that the CALPUFF3 modeling system was appropriately applied by 

SC DHEC in the assessment of visibility impairment in Class I areas for specific sources 

subject to the BART regulations. The BART regulations indicate that CALPUFF or 

other appropriate models can be used to determine if an individual source is anticipated to 

cause or contribute to impairment of visibility in Class I areas. The current regulatory 

niche for the CALPUFF modeling system in 40 CFR, part 51, Appendix W: Guideline on 

Air Quality Models (Appendix W) is for compliance with non-attainment New Source 

Review (NNSR)/ and Prevention of Significant Deterioration (PSD) permitting 

requirements for long range transport (i.e., greater than 50 KM) applications at Class I 

 

3 Note that EPA‟s reference to CALPUFF encompasses the whole CALPUFF modeling system, including 

CALMET/CALPUFF/CALPOST and other pre and post processors. The different versions of CALPUFF 

have corresponding versions of CALMET, CALPOST, etc. which may not be compatible with previous 

versions (e.g., the output from a newer version of CALMET may not be compatible with an older version 

of CALPUFF). The different versions of the CALPUFF modeling system are available from the model 

developer on the following website: http://www.src.com/verio/download/download.htm
54

areas. There is no preferred model for assessing visibility impact under BART. 

However, EPA believes that it is appropriate for the State of South Carolina to use the 

CALPUFF modeling system for its BART exemption and control determination 

modeling. 

VISTAS developed a “Protocol for the Application of CALPUFF for BART Analyses.” 

The final VISTAS BART Modeling Protocol (Revision 3.2, dated Aug. 6, 2006) states 

that VISTAS will use CALPUFF ver. 5.754 and CALMET ver. 5.7 (i.e., the VISTAS 

version of CALPUFF). No formal approval of the CALPUFF VISTAS version (either 

ver. 5.754 or 5.756) has been made by EPA Region 4. However, there has been an 

implied acceptance of the VISTAS CALPUFF version as EPA Region 4 has reviewed 

and commented on the VISTAS BART Modeling Protocol and the source-specific 

modeling protocols and reports that were developed by the South Carolina specific 

sources performing BART modeling. The VISTAS BART modeling protocol underwent 

an extensive stakeholder development and review process, that involved EPA, FLMs, 

industrial sources, trade groups, lawyers and other interested parties, before the State 

decided to require CALPUFF modeling to evaluate the BART requirements. 

The State required all BART-eligible sources to perform BART exemption modeling and 

to develop source-specific protocols that complied with the VISTAS protocol. EPA 

Region 4 provided reviews and comments on the source-specific protocols and their 

subsequent exemption modeling reports. 

New IMPROVE Equation

The CALPUFF model was simulated with the default inputs as recommended in the 

March 16, 2006 EPA memorandum, “Dispersion Coefficients for Regulatory Air Quality 

Modeling in CALPUFF.” A new methodology was used by the VISTAS states to 

process the mass concentrations from CALPOST (post-CALPUFF processor) using the 

new IMPROVE equation so that the BART analyses could consider both the old and new 

IMPROVE equations. The EPA Headquarters and other EPA regional offices and the 

Federal Land Managers (FLMs) from the National Park Service and the U.S. Fish and 

Wildlife Service consulted on the VISTAS innovative approach that was developed to 

utilize the new IMPROVE equation in the BART assessment and to determine the change 

in visibility impacts. While these other parties were consulted in preparation of EPA 

Region 4‟s response, the response represented the EPA Region 4 position on the new 

methodology. Use of the methodology by BART sources in States located in other EPA 

Regions would require consultation with the appropriate regional office. EPA required 

the State of South Carolina to submit a request to the EPA Region 4 Regional 

Administrator requesting the use of this new methodology for the BART CALPUFFbased modeling. The State submitted a letter dated September 13, 2007, justifying the 

need for this approach and approval from the Regional Administrator was provided to the 

State in a letter dated October 5, 2007. The methodology and State and Region 4 letters 

are located in the State‟s SIP submittal.

The new methodology uses a spreadsheet developed by VISTAS to post-process the 

visibility modeling output from the CALPUFF and CALPOST models. The spreadsheet 
55

implements the new IMPROVE equation for calculating visibility impacts that was 

adopted by the IMPROVE Steering Committee in December 2005. EPA Region 4 has 

previously provided comments indicating that new methodology is an alternative 

modeling approach and should meet the requirements in section 3.2 of Appendix W, 

Guideline on Air Quality Models, contained in 40 CFR part 51. EPA reviewed the 

State‟s rationale for using the new methodology. This demonstration included a rationale 

for the need to use the new IMPROVE equation, a discussion of the performance of the 

equation versus measured values, a submittal of the modified post-processing 

methodology, and documentation to support the development of concentrations for the 

different terms in the equation. Based on the demonstration provided in South Carolina‟s 

September 13, 2007, letter, EPA approved the State‟s request.

Sea Salt and New IMPROVE Equation for BART

EPA proposes to agree with the use of sodium ion (Na+) concentration data in the new 

IMPROVE equation for estimating background concentrations in the BART CALPUFFbased modeling. EPA continues to endorse the recommendations made by the 

IMPROVE Committee for the use of chloride ion data as the default procedure to 

estimate sea salt concentration. However, EPA believes that alternative approaches could 

be considered on a case-by-case basis, which is why EPA agrees with the alternative 

approach presented by South Carolina for the use of Na+ in the BART modeling. EPA

recognizes that a goal of modeling is to find the best method for estimating natural 

background levels for assessing visibility impacts.

EPA believes that based on our review of the materials presented by SC DHEC and 

consultations with Dr. Marc Pitchford, of the NOAA - Air Resources Laboratory, that 

there is a technical basis to support the use of other methods for determining the sea salt 

concentration for use in the new IMPROVE algorithm. This would be allowable on a 

case-by-case basis for those coastal Class I areas subject to BART analysis by the South 

Carolina sources. 

Three of the four facilities that are exempt from BART only if the alternative sodium 

method is used (i.e., DAK- Cooper River, MeadWestvaco, and International PaperGeorgetown), were requested to submit a reasonable progress control analysis so that SC 

DHEC could assess whether or not controls are reasonable under the regional haze 

regulations. The only facility that has not been requested to submit a reasonable progress 

control analysis is an electric generating facility (i.e., Santee Cooper- Jefferies) covered 

under CAIR.

SC DHEC has demonstrated that compliance with CAIR satisfies sources‟ requirements 

under the regional haze regulations for this first implementation period. In summary, SC 

DHEC concluded that additional SO2 control measures for South Carolina‟s EGUs would not 

be reasonable to achieve reasonable progress during this first implementation period. In 

reaching this decision, SC DHEC considered the four reasonable progress factors set forth in 

EPA‟s RHR as they apply to the State‟s entire EGU sector. In particular, the State took into 

account the factors of cost and time necessary for compliance in view of EPA‟s analysis 

supporting CAIR. Based on the analysis, SC DHEC concluded that additional SO2 control 
56

measures, beyond those needed to meet CAIR requirements, for South Carolina‟s EGUs 

would not be reasonable during this first implementation period based on a consideration of 

the reasonable progress statutory factors. This conclusion is bolstered by the fact that 

visibility improvement at the Cape Romain Wilderness Area is projected to exceed the 

uniform rate of progress in this first implementation period. EPA proposes to find acceptable 

South Carolina‟s methodology and determination that no additional controls beyond CAIR 

are reasonable for SO2 for affected South Carolina EGUs for the first implementation period. 

Contribution Threshold

With respect to the contribution threshold used in the CALPUFF modeling, the State was 

also required to justify its choice of the 0.5 dv contribution threshold for exempting 

sources from BART eligibility. The BART Guidelines state that “the appropriate 

threshold for determining whether a source „contributes to visibility impairment‟ may 

reasonably differ across states,” but, “[a]s a general matter, any threshold that you use for 

determining whether a source „contributes‟ to visibility impairment should not be higher 

than 0.5 deciviews.” The Guidelines affirm that states are free to use a lower threshold if 

they conclude that the location of a large number of BART-eligible sources in proximity 

of a Class I area justifies this approach. 

South Carolina used a contribution threshold of 0.5 deciview for determining which 

sources are subject to BART. SC DHEC concluded that, considering the results of the 

visibility impacts modeling conducted, a 0.5 deciview threshold was appropriate and a 

lower threshold was not warranted. South Carolina demonstrated that it is unlikely that 

multiple BART-eligible sources would simultaneously adversely impact visibility at 

Cape Romain at a level that would warrant a lower threshold value. For the South 

Carolina sources that were shown to be impacting the Wolf Island Class I Federal area in 

Georgia, South Carolina demonstrated that they were located far from Wolf Island and 

that the majority of the individual BART-eligible sources had visibility impacts well 

below 0.5 deciview. 

EPA proposes to agree with the State‟s rationale for choosing this threshold value since 

there are a limited number of in and out of state sources that impact the various Class I 

areas in the State. In addition there are a limited number of sources in close proximity to 

each of the Class I areas. Considering results of the visibility impacts modeling 

conducted (see SC SIP, Appendix H.6), a 0.5 dv threshold was appropriate and a lower 

threshold was not warranted since the majority of the visibility impacts were well below 

0.5 deciview. Also, even though several sources impacted each Class I area, the overall 

impacts were low from the BART sources, and EPA has not made any adverse comments 

on the use of the CALPUFF VISTAS versions. 

References used in the EPA review: 

1. 40 CFR part 51, Appendix W: Guideline on Air Quality Models.

2. October 5, 2007, letter from James I. Palmer, Regional Administrator, US EPA 

Region 4, to Robert W. King, Jr., P.E, Deputy Commissioner, South Carolina 
57

Department of Health and Environmental Control, Approval for the use of the 

VISTAS methodology for use of the New IMPROVE equation with CALPUFF 

model results. 

3. 40 CFR part 51, Appendix Y: Guidelines for BART Determinations Under the 

Regional Haze Rule 

4. IWAQM. 1998. Interagency Workgroup on Air Quality Modeling (IWAQM) 

Phase 2 Summary Report and Recommendations for Modeling Long-Range 

Transport and Impacts on Regional Visibility. EPA-454/R-98-019. U.S. 

Environmental Protection Agency, Office of Air Quality Planning and Standards, 

Research Triangle Park, NC. 

5. VISTAS, 2006. Tombach, I., P. Brewer, T. Rogers, and C. Arrington, Protocol 

for the Application of the CALPUFF Model for Analysis of Best Available Retrofit 

Technology (BART) Revision 2 – 3/9/06 developed through consultation with 

EPA, the FLMs, VISTAS state and local Agencies and industry stakeholders 

VISTAS, 2006. Tombach, I., P. Brewer, T. Rogers, and C. Arrington. Located at 

http://www.vistassesarm.org/documents/BARTModelingProtocol_rev3.2_31Aug06.pdf.

6. March 16, 2006, EPA memorandum from Dennis Atkinson to Kay T. Prince on 

Dispersion Coefficients for Regulatory Air Quality Modeling in CALPUFF.

7. Additional Regional Haze Questions, EPA, September 27, 2006 Revision. 

Answers to questions that PA received from various States and Regional Planning 

Organizations (RPOs) related to the submission of regional haze SIPs under the 

program described by 40 CFR 51.308. This document provides guidance to the 

State air pollution control agencies and the general public on meeting the regional 

haze SIP requirements.
58

III. Evaluation of Regional Haze SIP Submittal

D. Best Available Retrofit Technology (BART) Requirements

D.3. Identification of Sources Addressed by CAIR: States which adopt the CAIR cap 

and trade program for SO2 and NOx are allowed to apply CAIR controls as a substitute 

for controls required under BART. The SIP should include a list of all BART-eligible 

sources within the State for which the CAIR rule is being applied.

State Regional Haze Submittal

SC SIP Narrative, Page 86:

Six of South Carolina‟s BART-eligible sources are EGUs. EPA has determined that, as a 

whole, the CAIR cap-and-trade program will improve visibility more than implementing 

BART for individual sources in states which participate in the federal CAIR program. A 

state that opts to participate in the CAIR program need not require affected BART 

eligible EGUs to install BART for SO2 or NOX emissions. Given that South Carolina is 

participating in CAIR and accepts EPA‟s overall finding that CAIR “substitutes” for 

BART for SO2 and NOX, SC‟s EGUs were allowed to submit BART exemption modeling 

demonstrations for PM emissions only. Four of the six EGUs demonstrated that they do 

not contribute to visibility impairment in South Carolina‟s Class I Federal area. These 

facilities were SCE&G – Canadys plant and Santee Cooper‟s – Jefferies, Winyah, and 

Grainger facilities.

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision. EPA believes that the State has appropriately identified the BART-eligible 

sources and those sources subject to BART controls. South Carolina opted to have CAIR 

satisfy BART for SO2 and NOx for affected CAIR EGUs, as allowed under the Regional 

Haze regulations. As explained in Section III.C.1–EPA Findings, the State‟s 

demonstration regarding CAIR and reasonable progress for EGUs, and other provisions 

in this SIP revision, are based on CAIR and thus, the Agency proposes to issue a limited 

approval of the State‟s regional haze SIP revision. In a separate action, EPA has 

proposed a limited disapproval of the South Carolina regional haze SIP because of 

deficiencies in the State‟s regional haze SIP submittal arising from the State‟s reliance on 

CAIR to meet certain regional haze requirements. See 76 FR 82219 (December 30, 

2011). EPA is not proposing to take action in this rulemaking on issues associated with 

South Carolina‟s reliance on CAIR in its regional haze SIP.
59

III. Evaluation of Regional Haze SIP Submittal

D. Best Available Retrofit Technology (BART) Requirements

D.4. Source Specific BART Determinations: For each BART-eligible source in the 

State subject to BART, a determination of BART based on an analysis of the best system 

of continuous emission control technology available and associated emission reductions 

achievable (unless the State demonstrates that an emissions trading program or other 

alternative will achieve greater reasonable progress toward natural visibility conditions). 

To address the requirements for BART, the State must take into consideration the “Five 

Factors” from 51.308(e)(1)(ii)(A): (1) the technology available, (2) the costs of 

compliance, (3) the energy and non-air quality environmental impacts of compliance, any 

pollution control equipment in use at the source, (4) the remaining useful life of the 

source, and (5) the degree of improvement in visibility that may reasonably be anticipated 

to result from the use of such technology.

State Regional Haze Submittal

SC SIP Narrative, Pages 86-88:

SCE&G Wateree: SCE&G Wateree Station is located in Eastover, South Carolina. The 

station consists of two identical pulverized coal-fired, wet bottom boilers. The two boilers 

produce superheated steam, which is used in the two dedicated turbine generators Units 

1 and 2 are equipped with fabric filter baghouses to control PM emissions, and low- NOX 

burners and SCR to control NOX emissions. Although Units 1 and 2 commenced 

commercial operation in the early „70s, there is no near-term limitation on the useful life 

of this unit.

SCE&G also plans to install two wet limestone scrubbers to control SO2 emissions in the 

summer (July/August) of 2009. Wateree Station Units 1 and 2 will be retrofitted with a 

flue gas desulfurization (FGD) system using a limestone slurry in a spray tower to 

remove SO2 from the gas stream. Although designed to control SO2 emissions, the FGD 

system will provide the added benefit of removing sulfates, a principal constituent of 

condensable PM10. Installing a FGD system will result in added improvements in 

visibility impairment attributable to Units 1 and 2.

The installation of the FGD systems will result in a visibility improvement of about 59 

percent, in terms of delta dv relative to natural conditions, on the worst-case visibility 

day. Furthermore, as shown in Table 7.8.2-1 above, the 98th percentile delta dv resulting 

from the installation of the FGD systems is well below the 0.5 delta dv threshold, used to 

determine whether a source contributes to visibility impairment as stated in the BART 

Guidelines. In addition, an analysis of annualized costs associated with additional PM10

control options determined that any additional control measure is not cost effective in

terms of visibility improvements.

SCE&G Williams: South Carolina Electric & Gas (SCE&G) Williams Station is located

in Goose Creek, South Carolina. The station consists of a single pulverized coal-fired,

dry bottom boiler. The boiler produce superheated steam, which is used in a turbine

generator. Although Unit 1 commenced commercial operation in 1973, there is no near 
60

term limitation on the useful life of this unit. Unit 1 is currently equipped with low-NOX 

burners and SCR to control NOX emissions and an electrostatic precipitator (ESP) to 

control PM10 emissions, the later of which has been demonstrated to achieve performance 

levels comparable to those being specified as BACT for new coal-fired boilers. The 

existing control device, therefore, is considered representative of BART for PM10. 

In October 2009, SCE&G plans to retrofit Williams Station Unit 1 with a FGD system

using a limestone slurry in a spray tower to remove SO2 from the gas stream. Although

designed to control SO2 emissions, the FGD system will provide the added benefit of

removing sulfates, a principal constituent of condensable PM10. PM10 emissions will be

reduced from 925 tpy to 464 tpy following the installation of the FGD system. This 50

percent reduction is attributable to the removal of condensable PM10, principally 

sulfates, in the FGD system. The installation of the FGD system will result in a visibility 

improvement of about 35 percent, in terms of delta dv relative to natural conditions, on 

the worst-case visibility day. Furthermore, the 98th percentile delta dv resulting from the 

installation of the FGD system is only slightly above the 1.0 delta dv threshold (2 

occurrences in 3 years), used to determine whether a source could causes visibility 

impairment as stated in the BART Guidelines. The installation of any of the PM10 control 

options will only result in an additional visibility improvement of less than 1 percent on 

the worst-case visibility day. Furthermore, the annual costs associated with the PM10 

control options are not cost effective in terms of visibility improvements.

76BU

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision. EPA believes that the State appropriately documented the technical analysis to 

assess the need for and implementation of BART controls as applicable for those nonCAIR EGU emission units of PM10, SO2 and NOx precursor emissions. This involved 

identification of existing controls on applicable emission units, potential control options 

for applicable emission precursors, and the successful application of the five factors to 

determine the feasibility of controls that constituted BART. 
61

III. Evaluation of Regional Haze SIP Submittal

D. Best Available Retrofit Technology (BART) Requirements

D.5. Enforceability of BART: For each BART-eligible source in the State subject to 

BART, the SIP should include emission limitations representing BART and schedules for 

compliance with BART. For each BART-eligible source in the State subject to BART, 

the SIP must include a requirement that each source subject to BART be required to 

install and operate BART as expeditiously as practicable, but in no event later than five

years after approval of the implementation plan revision and a requirement that each 

source subject to BART maintains the control equipment required by this subpart and 

establishes procedures to ensure such equipment is properly operated and maintained. 

State Regional Haze Submittal

SC SIP Appendix H, Page H-65:

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision. SC DHEC determined that two SCE&G facilities, Williams and Wateree, did 

not model out of BART. Both these facilities installed fluidized gas desulphurization 

SO2 controls in order to comply with CAIR. These additional SO2 controls will also 

provide PM10 reductions. SC DHEC has included these controls in the applicable title V 

permits. 
62

III. Evaluation of Regional Haze SIP Submittal

E. Coordination of Regional Haze and RAVI Requirements

The State must revise its plan to provide for review and revision of a coordinated longterm strategy for addressing reasonably attributable and regional haze visibility 

impairment.

State Regional Haze Submittal

South Carolina did not explicitly address this provision but it has updated and addressed 

all relevant provisions:

Monitoring (SC SIP Narrative, Pages 109-111):

The primary monitoring network for regional haze, both nationwide and in South 

Carolina, is the IMPROVE network. Given that IMPROVE monitoring data from 2000-

2004 serve as the baseline for the regional haze program, the future regional haze 

monitoring strategy must necessarily be based on, or directly comparable to, IMPROVE.

The IMPROVE measurements provide the only long-term record available for tracking 

visibility improvement or degradation and therefore South Carolina intends to rely on the

IMPROVE network for complying with the regional haze monitoring requirement in the 

Regional Haze Rule.

There is currently one IMPROVE site in the South Carolina, representing the Cape

Romain National Wildlife Refuge Class I Federal area (ROMA1). The State supplement 

the IMPROVE sampling by operating additional co-located monitoring. Monitoring at

Cape Romain includes:

• A Tapered Element Oscillating Microbalance (TEOM) for continuously measuring 

PM2.5 mass concentration;

• An Aethalometer for continuously measuring Black Carbon;

• An integrating nephelometer, supported by VISTAS, for continuously measuring light 

scattering; and

• Continuous monitoring of NO2 and SO2 precursor gasses.

The Optec NGN-2 Nephalometer has been transferred to South Carolina. The operation

and data reporting is supported by VISTAS through 2008. Funding will be sought to

continue operation but is not assured

.

Additional haze-related measurements were made in South Carolina in 2002-2005 as 

part of special monitoring studies by the VISTAS regional planning organization. These

studies were intended to better understand source contributions to PM2.5 mass and

visibility. They included continuous monitoring of sulfate, nitrate, and carbon to better 

understand daily trends in PM2.5, detailed analyses of carbon collected on high volume

filters to identify source contributions to carbon, and additional analyses of sodium and

ammonium on IMPROVE filter samples. Funding does not exist to continue these special 

studies; however, the equipment has been transferred to SC DHEC.

South Carolina has acquired several continuous sulfate monitors and expects to operate

tthem at urban and rural sites to further the understanding of both PM2.5 and visibility
63

formation and trends in South Carolina. SC DHEC will operate the units discussed above

as long as funds allow.

In addition, SC DHEC operates a fairly comprehensive PM2.5 network of the filter based

Federal Reference Method samplers, continuous mass monitors (TEOMs), STN protocol

filter based speciated samplers and the continuous speciated particulate monitors

described above. These PM2.5 measurements help SC DHEC characterize air pollution

levels in areas across the state, and therefore aid in the analysis of visibility improvement

in and near the Class I areas.

The IMPROVE measurements are central to South Carolina‟s regional haze monitoring

strategy, and it is difficult to visualize how the objectives listed above could be met

without the monitoring provided by IMPROVE. Any reduction in the scope of the

IMPROVE network in South Carolina and neighboring Class I Federal areas would

jeopardize the State‟s ability to demonstrate reasonable progress toward visibility

improvement in its Class I areas and plan for appropriate future progress. In particular,

South Carolina‟s regional haze strategy relies on emission reductions that will result 

from the CAIR and reductions in neighboring States, which occur on different time scales 

and will most likely not be spatially uniform. Monitoring at representative Class I area is 

important to document the different air quality responses to the emissions reductions.

Because the current IMPROVE monitor at Cape Romain represents a unique Class I

Federal area, and a significant component of the contributions are regional, the 

reduction of the IMPROVE network by shutting down the existing IMPROVE site or any 

the closer IMPROVE monitoring sites impedes tracking the progress or planning 

improvements at Cape Romain. In the event the Cape Romain monitoring is scheduled for 

elimination, South Carolina, in consultation with the US EPA and relevant FLMs, will 

develop an alternative approach for meeting the tracking goal, perhaps by seeking 

contingency funding to carry out limited monitoring or by relying on data from nearby 

urban monitoring sites to demonstrate trends in speciated PM2.5 mass.

Data produced by the IMPROVE monitoring network will be used nearly continuously

for preparing the five-year progress reports and the 10-year SIP revisions, each of which

relies on analysis of the preceding five years of data. Consequently, the monitoring data

from the IMPROVE sites needs to be readily accessible and to be kept up to date.

Presumably, IMPROVE will continue to process information from its own measurements

at about the same pace and with the same attention to quality as it has shown in the

recent past. The VIEWS web site has been maintained by VISTAS and the other Regional

Planning Organizations to provide ready access to the IMPROVE data and data analysis

tools. South Carolina is encouraging VISTAS and the other RPOs to maintain VIEWS or

a similar data management system to facilitate availability analysis of the IMPROVE and

visibility related data.

Periodic Submittals (SC SIP Narrative, Page 116):

40 CFR Section 51.308(f) requires South Carolina to revise its regional haze SIP and 

submit a plan revision to EPA by July 31, 2018, and every ten years thereafter. In 
64

accordance with the requirements listed in Section 51.308(f) of the RHR, South Carolina 

commits to revising and submitting this regional haze SIP by July 31, 2018, and every ten 

years thereafter.

In addition, Section 51.308(g) requires periodic reports evaluating progress towards the

RPGs established for each mandatory Class I area. “The EPA believes that a 

requirement for regular SIP revisions will result in a more effective program over time 

and provide a focus for demonstrating ongoing progress and making mid-course 

corrections in emission strategies” (62 FR 41151).

In accordance with the requirements listed in Section 51.308(g) of the RHR, South

Carolina commits to submitting a report on reasonable progress to EPA every five years 

following the initial submittal of the SIP. The report will be in the form of a SIP revision.

The reasonable progress report will evaluate the progress made towards the RPG for 

each mandatory Class I Federal area located within South Carolina and in each 

mandatory Class I Federal area located outside South Carolina that may be affected by 

emissions from South Carolina sources.

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision. Under EPA‟s RAVI regulations, the RAVI portion of a state SIP must address 

any integral vistas identified by the FLMs pursuant to 40 CFR 51.304. See 40 CFR 

51.302. An integral vista is defined in 40 CFR 51.301 as a “view perceived from within 

the mandatory Class I federal area of a specific landmark or panorama located outside the 

boundary of the mandatory Class I federal area.” Visibility in any mandatory Class I area

includes any integral vista associated with that area. The FLMs did not identify any 

integral vistas in South Carolina. In addition, the Class I area in South Carolina is not 

experiencing RAVI, nor are any of its sources affected by the RAVI provisions. Thus, 

the December 17, 2007, South Carolina regional haze SIP submittal does not explicitly 

address the two requirements regarding coordination of the regional haze with the RAVI 

LTS and monitoring provisions. South Carolina has, however, previously made a 

commitment to address RAVI should the FLM certify visibility impairment from an 

individual source.4 EPA proposes to find that this regional haze submittal appropriately 

supplements and augments South Carolina‟s RAVI visibility provisions to address 

regional haze by updating the monitoring and LTS provisions as summarized below in 

this section.

In the December 17, 2007, submittal, SC DHEC updated its visibility monitoring 

program and developed a LTS to address regional haze. Also in this submittal, SC 

DHEC affirmed its commitment to complete items required in the future under EPA‟s 

RHR. Specifically, SC DHEC made a commitment to review and revise its regional haze 

implementation plan and submit a plan revision to EPA by July 31, 2018, and every 10 

years thereafter. See 40 CFR 51.308(f). In accordance with the requirements listed in 40

CFR 51.308(g) of EPA‟s regional haze regulations and 40 CFR 51.306(c) of the RAVI 

 

4

South Carolina submitted its visibility SIP revisions addressing RAVI on June 3, 1985, which EPA 

approved on January 21, 1986 (51 FR 2698). 
65

LTS regulations, SC DHEC made a commitment to submitting a report to EPA on 

progress towards the RPGs the mandatory Class I area located within South Carolina and 

in each mandatory Class I area located outside South Carolina which may be affected by 

emissions from within South Carolina. The progress report is required to be in the form 

of a SIP revision and is due every five years following the initial submittal of the regional 

haze SIP. See 40 CFR 51.308(g). Consistent with EPA‟s monitoring regulations for 

RAVI and regional haze, South Carolina will rely on the IMPROVE network for 

compliance purposes, in addition to any RAVI monitoring that may be needed in the 

future. See 40 CFR 51.305, 40 CFR 51.308(d)(4). Also, the South Carolina new source 

review rules, previously approved in the State‟s SIP, continue to provide a framework for 

review and coordination with the FLMs on new sources which may have an adverse 

impact on visibility in either form (i.e., RAVI and/or regional haze) in any Class I area. 

The original South Carolina visibility SIP submitted to EPA June 3, 1985, addressing the 

monitoring and LTS requirements in 40 CFR 51.305 and 40 CFR 51.306, respectively, 

was supplemented by an EPA regulation, 40 CFR 52.2132, on July 12, 1985 (50 FR 

28544), as amended on November 24, 1987 (52 FR 45132). The 1985 and 1987 EPA 

actions incorporate 40 CFR 52.26 and 40 CFR 52.29 into the South Carolina SIP and 

continue to be in effect. Because the December 17, 2007, regional haze submittal 

appropriately addresses the monitoring and LTS requirements in 40 CFR 51.305 and 40 

CFR 51.306, and supersedes these previous requirements, EPA is proposing to rescind 

the federal regulations in 40 CFR 52.2132 and rely on the provisions in this December 

17, 2007, submittal to meet these requirements.
66

III. Evaluation of Regional Haze SIP Submittal

F. Monitoring Strategy and Other Implementation Requirements

Monitoring Strategy: The SIP must include a monitoring strategy for measuring, 

characterizing, and reporting of regional haze visibility impairment that is representative 

of all mandatory Class I Federal areas within the State and/or summarize monitoring 

strategy of states with affected mandatory Class I Federal areas. Compliance with this 

requirement may be met through participation in the Interagency Monitoring of Protected 

Visual Environments (IMPROVE) network. 

Other Requirements: The implementation plan must also provide for the following:

A. The establishment of any additional monitoring sites or equipment needed to 

assess whether reasonable progress goals to address regional haze for all 

mandatory Class I Federal areas within the State are being achieved.

B. Procedures by which monitoring data and other information are used in 

determining the contribution of emissions from within the State to regional haze 

visibility impairment at mandatory Class I Federal areas both within and outside 

the State.

C. The reporting of all visibility monitoring data at least annually for each mandatory 

Class I Federal area in the State. To the extent possible, the State should report 

monitoring data for visibility electronically and use of the Visibility Information 

Exchange Web System (VIEWS) is encouraged.

D. Other elements, including reporting, recordkeeping, and other measures, 

necessary to assess and report on visibility.

State Regional Haze Submittal

SC SIP Narrative, Pages 109-111:

The primary monitoring network for regional haze, both nationwide and in South

Carolina, is the IMPROVE network. Given that IMPROVE monitoring data from 2000-

2004 serve as the baseline for the regional haze program, the future regional haze

monitoring strategy must necessarily be based on, or directly comparable to, IMPROVE.

The IMPROVE measurements provide the only long-term record available for tracking

visibility improvement or degradation and therefore South Carolina intends to rely on the

IMPROVE network for complying with the regional haze monitoring requirement in the

Regional Haze Rule.

There is currently one IMPROVE site in the South Carolina, representing the Cape

Romain National Wildlife Refuge Class I Federal area (ROMA1). The State supplements

the IMPROVE sampling by operating additional co-located monitoring. Monitoring at

Cape Romain includes:

• A Tapered Element Oscillating Microbalance (TEOM) for continuously measuring 

PM2.5 mass concentration;

• An Aethalometer for continuously measuring Black Carbon;

• An integrating nephelometer, supported by VISTAS, for continuously measuring light 

scattering; and

• Continuous monitoring of NO2 and SO2 precursor gasses.
67

The Optec NGN-2 Nephalometer has been transferred to South Carolina. The operation

and data reporting is supported by VISTAS through 2008. Funding will be sought to

continue operation but is not assured.

Additional haze-related measurements were made in South Carolina in 2002-2005 as 

part of special monitoring studies by the VISTAS regional planning organization. These

studies were intended to better understand source contributions to PM2.5 mass and

visibility. They included continuous monitoring of sulfate, nitrate, and carbon to better

understand daily trends in PM2.5, detailed analyses of carbon collected on high volume

filters to identify source contributions to carbon, and additional analyses of sodium and

ammonium on IMPROVE filter samples. Funding does not exist to continue these special 

studies; however, the equipment has been transferred to SC DHEC. South Carolina has 

acquired several continuous sulfate monitors and expects to operate them at urban and 

rural sites to further the understanding of both PM2.5 and visibility formation and trends 

in South Carolina. SC DHEC will operate the units discussed above as long as funds 

allow.

In addition, SC DHEC operates a fairly comprehensive PM2.5 network of the filter based

Federal Reference Method samplers, continuous mass monitors (TEOMs), STN protocol

filter based speciated samplers and the continuous speciated particulate monitors

described above. These PM2.5 measurements help SC DHEC characterize air pollution

levels in areas across the state, and therefore aid in the analysis of visibility improvement

in and near the Class I areas.

The IMPROVE measurements are central to South Carolina‟s regional haze monitoring

strategy, and it is difficult to visualize how the objectives listed above could be met

without the monitoring provided by IMPROVE. Any reduction in the scope of the

IMPROVE network in South Carolina and neighboring Class I Federal areas would

jeopardize the State‟s ability to demonstrate reasonable progress toward visibility

improvement in its Class I areas and plan for appropriate future progress. In particular,

South Carolina‟s regional haze strategy relies on emission reductions that will result 

from the CAIR and reductions in neighboring States, which occur on different time scales 

and will most likely not be spatially uniform. Monitoring at representative Class I area is

important to document the different air quality responses to the emissions reductions.

Because the current IMPROVE monitor at Cape Romain represents a unique Class I

Federal area, and a significant component of the contributions are regional, the 

reduction of the IMPROVE network by shutting down the existing IMPROVE site or any 

the closer

IMPROVE monitoring sites impedes tracking the progress or planning improvements at

Cape Romain. In the event the Cape Romain monitoring is scheduled for elimination,

South Carolina, in consultation with the US EPA and relevant FLMs, will develop an

alternative approach for meeting the tracking goal, perhaps by seeking contingency

funding to carry out limited monitoring or by relying on data from nearby urban

monitoring sites to demonstrate trends in speciated PM2.5 mass.

Data produced by the IMPROVE monitoring network will be used nearly continuously

for preparing the five-year progress reports and the 10-year SIP revisions, each of which

relies on analysis of the preceding five years of data. Consequently, the monitoring data

from the IMPROVE sites needs to be readily accessible and to be kept up to date. 

Presumably, IMPROVE will continue to process information from its own measurements
68

at about the same pace and with the same attention to quality as it has shown in the 

recent past. The VIEWS web site has been maintained by VISTAS and the other Regional

Planning Organizations to provide ready access to the IMPROVE data and data analysis

tools. South Carolina is encouraging VISTAS and the other RPOs to maintain VIEWS or

a similar data management system to facilitate availability analysis of the IMPROVE and

visibility related data.

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision.
69

III. Evaluation of Regional Haze SIP Submittal

G. Emission Inventory (40 CFR 51.308(d)(4)(v) (See also TSD Section III.C.))

The SIP must include a statewide inventory of emissions of pollutants that are reasonably 

anticipated to cause or contribute to visibility impairment in any mandatory Class I 

Federal area within the State. The inventory must include emissions for a baseline year, 

emissions for the most recent year for which data are available, and estimates of future 

projected emissions, and a commitment to update the inventory periodically.

State Regional Haze Submittal

SC SIP Narrative, Pages 29-30:

Section 51.308(d)(4)(v) of the RHR requires a statewide emissions inventory of pollutants 

that are reasonably anticipated to cause or contribute to visibility impairment in any 

mandatory Class I Federal area. An inventory was developed for the baseline year 2002 

and estimated for 2009 and 2018. The pollutants inventoried include VOCs, nitrogen 

oxides (NOX), fine particulate (PM2.5), coarse particulate (PM10), ammonia, and SO2. In 

general, the baseline emissions inventory for 2002 was developed using control

information for South Carolina. A complete detailed discussion of the baseline emissions

inventory is contained in Appendix D.3.

There are five different emission inventory source classifications, stationary point and

area sources, off-road and on-road mobile sources, and biogenic sources. Stationary

point sources are those sources that emit greater than a specified tonnage per year and 

the data is provided at the facility level. Stationary area sources are those sources whose

emissions are relatively small but due to the large number of these sources, the collective

emissions could be significant (e.g., dry cleaners, service stations, etc.) These types of

emissions are estimated on the county level. Off-road mobile sources are equipment that

can move but do not use the roadways (e.g., lawn mowers, construction equipment,

railroad locomotives, aircraft, etc.). The emissions from these sources, like stationary

area sources, are estimated on the county level. On-road mobile sources are 

automobiles, trucks, and motorcycles that use the roadway system. The emissions from 

these sources are estimated by vehicle type and road type and are summed to the county 

level. Biogenic sources are natural sources like trees, crops, grasses, and natural decay 

of plants. The emissions from these sources are estimated on a county level. In addition 

to the various source classifications, there are also various types of emission inventories. 

The first is the actual base year inventory. This inventory is the base year emissions that 

correspond to the meteorological data; for this modeling effort it is 2002.

These emissions are used for evaluating the air quality model performance.

The second type of inventory is the typical base year inventory. This inventory is similar

to the actual base year; however, for sources that may have significant changes from 

year to year, a more typical emission value is used. In this modeling effort, typical 

emissions were developed for the EGUs and the wildland fire emissions. The air quality 

modeling results using these emissions are used in calculating the relative reduction 

factors used in the attainment demonstration test.

The detailed discussions of the emissions inventory development can be found in 

Appendices D.1 and D.4.c.
70

SC SIP Narrative, Page 33:

SC SIP Narrative, Pages 57-59:

The Base G inventories for 2009 and 2018 account for (post-2002) emission reductions

from promulgated and proposed federal, state, local, and site-specific control programs 

as of July 1, 2004. In general, emissions inventories were developed for 2009 and 2018

using current control information in South Carolina: the 2002 inventory was grown using

EGAS6, MOBILE6, and IPM for EGUs.

For EGUs, IPM results were adjusted based on State and local (S/L) agency knowledge

of planned emission controls at specific EGUs. For non-EGUs, we used recently updated

growth and control data consistent with the data used in EPA‟s CAIR analyses

supplemented by S/L agency data and updated forecasts from the Department of Energy

(DOE).

Area source controls were estimated using known state-level Stage I controls on gasoline

dispensing facilities and open burning estimates, as well as controls used to project

emissions for EPA‟s Heavy Duty Diesel rulemaking and for the CAIR rulemaking.

Mobile source controls included local controls underlying the 2002 baseline inventory

(vehicle emission inspection, Stage II vapor recovery, anti-tampering, etc.) with changes

based on specific State input. Non-road control data and projections for 1996, 2010,

2015, and 2020 were obtained from the EPA's CAIR Technical Support Document, and 

straight line projections were used to estimate 2009 and 2018 levels.

The following bar charts show expected decreases in emissions of SO2 and NOX across 

the VISTAS states from 2002 through 2018. (Similar charts for other visibility impairing

pollutants are contained in Appendix H.5). Note that for SO2 in particular, which is the

largest contributor to haze in the VISTAS region, emissions are expected to decrease

dramatically between 2002 and 2018. However, EGU emissions will remain the largest

contributor, comprising more than half of remaining SO2 emissions in every state.

56BTable 7.2.3-1 is a summary of the 2009 Base G2emission inventory. The complete

inventory and discussion of the methodology is contained in Appendix D.2 (a, b, and c).
71

Table 7.2.3-2 is a summary of the 2018 Base G2 emission inventory. The complete

inventory and discussion of the methodology is contained in Appendix D. 2 (a, b, and c).

SC SIP Narrative, Page 117:

All requirements listed in 51.308(g) shall be addressed in the SIP revision for reasonable

progress.

More specifically, the initial 5-year Progress Report (due in 2013) will examine the effect

of emission reductions as well as seek to evaluate the effectiveness of emission

management measures implemented. Therefore this Report will provide for a comparison 

of emission inventories, ultimately expressing the change in visibility for the most 

impaired and least impaired days over the past five years. Appendix K references

recommendations to consider when performing mid-course reviews. Moreover, due to the 

uncertainty of some measures, this Progress Report will also provide SC DHEC the 

opportunity to evaluate the overall effectiveness of proposed measures to reduce visibility 

impairment to include the effect of state and federal measures such as CAIR.

EPA Findings: EPA proposes to find that South Carolina has adequately addressed this 

provision. 
72

IV. Conclusion

EPA is proposing a limited approval of a revision to the South Carolina SIP submitted by 

the State of South Carolina on December 17, 2007, as meeting some of the applicable 

regional haze requirements as set forth in sections 169A and 169B of the CAA and in 40 

CFR 51.300-308, as described previously in this action. Also in this action, EPA is 

proposing to rescind the federal regulations in 40 CFR 52.2132 that were approved into 

the South Carolina SIP on July 12, 1985, and November 24, 1987, and to rely on the 

provisions in South Carolina‟s December 17, 2007, SIP revision to meet the monitoring 

and LTS requirements for RAVI.