UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 4 ATLANTA FEDERAL CENTER 61 FORSYTH STREET ATLANTA, GEORGIA 30303-8960

Ms. Sheila C. Holman Director Division ofAir Quality North CarolinaDepartment of

Environment and Natural Resources 1641 Mail Service Center Raleigh, North Carolina 27699-1641

Dear Ms. Holman: March 9, 2011

As we discussed recently with you and your staff, the U.S

. Environmental Protection Agency (EPA) has determined that it is importantthat we clarify our interpretation and expectations regarding Federal Land Manager (FLM) notification and visibility assessment requirements applicable to proposed new and modified sources subjectto the CleanAir Act's New Source Review (NSR) program. We appreciate the investment ofyourtime in trying to resolve these complex issues as well as your commitmentto implementthese requirements in accordance withEPA's interpretation ofthe applicable federal regulations and North Carolina's approved state implementationplan (SIP). There are, however, some statements made bythe North CarolinaDepartment ofEnvironment and Natural Resources (NC DENR) in its recent filing with the North Carolina Environmental Management Commission (EMC) ("Respondent's Written Exceptions and Argument") and the presentation entitled "PSD Permitting

- The State Program, EMC Meeting- March 10,2011"that do not accurately reflect EPA interpretations of its regulations. Therefore, we have concluded that itis inthe best interest ofall concerned for EPA to explain exactly how it expects North Carolina as well as other states to implementthe FLM notification and visibility assessmentrequirements.

RegardingNorth Carolina's obligationto notify the FLM ofany proposed new major

sources or major modifications to existing sources that "may affect" visibility as required pursuant to 40 C.F.R. 

### § 307(a)(l), we recognize and appreciate that NC DENRhas committed to provide the FLM with timely notice ofany suchproposed source. As we discussed, EPA expects NC DENRto interpret the phrase "may affect" as it appears inNorth Carolina's SIP (and in NC DENR's recently promulgatedrevisions at 15ANCAC 02D.0530(t)(2) and 15ANCAC 02D.0531(m)(3)) consistent withthe interpretationprovided inEPA'sNew Source Review Workshop Manual (draft, Oct. 1990). Specifically, a proposed new ormodified source "may affect" visibility in a Class I areaifit would be located within 100 kilometers (km) ofa Class I
area, or ifthe source would be located further than 100 km from a Class I area but other factors (such as the proposed source's size) raise concerns about potential visibility impacts. Under such circumstances, EPA expects NC DENRto provide the FLMwith written notification ofthe

Internet Address (URL) • http://www.epa.gov Recycled/Recyclable. Prinled wHh vegetableon Based Inks on Recycled Paper (Minimum 30% Postconsumer)proposed new ormodified source "within 30 days ofreceipt ofand at least 60 days priorto public hearing by the State onthe application for a permitto construct." 

### See 40 C.F.R. 

### § 51.307(a)(1). EPA disagrees with the interpretation of"may affect" provided by NC DENRto the EMC in its recent briefing, specifically, thatthe term "may affect" is synonymous with "has the potential to exceed a Class I increment." 

### See Respondent's Written Exchange and Argument, p. 4; 

### see also pp. 20-26. The FLM notificationrequirement is notrelated to orcontingentupon the analysis performed to determine whether the Class I increment is exceeded.

As we discussed on a recent call with your staff, EPA's regulations instruct that the FLM notification described above must "include an analysis ofthe anticipated impacts on visibility in any Federal Class I area." 

### See 40 C.F.R. 

### § 51.307(a)(1). This analysis involves an assessment of how a proposed new ormodified source's emissions would affect visibility as compared against what visibility would be in a Class I areaunder 

### natural conditions. The requirementthat the visibility assessment evaluate the source's impact on natural conditions is clearly stated in EPA's regulations. Specifically, the regulations define "adverse impact on visibility" as "forpurposes ofsection 307, 

### visibility impairmentwhich interferes withthe management, protection, preservation, or enjoyment ofthe visitor's visual experience ofthe Federal Class I area." 40 C.F.R. § 51.301 (emphasis added). The term "visibility impairment" is defined as "anyhumanly perceptible change in visibility (light extinction, visual range, contrast, coloration) 

### from that which wouldhave existedunder natural conditions." Id. (emphasis added). Finally, "natural conditions" is defined as "naturally occurring phenomenathat reduce visibility as measured in
terms oflight extinction, visual range, contrast, or coloration." 

### Id. In sum, under the plain language ofthe federal regulations, the required assessment ofa proposed new ormodified source's visibility impacts must involve an analysis ofhow the project's emissions would impact natural conditions. The regulatory provisions quoted above are expressly incorporated into North Carolina's SIP and are binding onNC DENR.

EPA disagrees with NC DENR's contention 

### in its briefing to the EMC that EPA requires the adverse impact analysis to be "based on current background visual range conditions." 

### See Respondent's Written Exchange and Argument, p. 5. As explained above, EPA's regulations unambiguously require thatthe visibility assessment involve an analysis ofthe project's visibility impacts as comparedto "thatwhich would have existed under natural conditions." This does not
mean, however, that current conditions are irrelevant to the ultimate determination ofwhether the visibility impairment caused by a proposed new or modified source rises to the level ofan "adverse impact onvisibility." Asprovided in EPA's regulations, such a determination involves

a broad examination ofwhether any visibility impairment would "interfere[] withthe management, protection, preservation, or enjoyment ofthe visitor's visual experience ofthe Federal Class I area." 40 C.F.R. 

### § 51.301. Current visibility conditions may be relevant to that determination. Furthermore, even ifthe FLMultimately concludes that a proposed new or modified source will have an adverse impact on visibility, the state retains the right to decide differently and authorize the source's construction. 

### See 40 C.F.R. § 51.307(a)(3). In making such a decision, the State can consider currentvisibility conditions.

Finally, please note that in accordance with EPA's regulations, it is the State's responsibility to provide the FLM with modeling results demonstrating a project's anticipated visibility impacts as measured against natural conditions. 

### See 40 C.F.R. 

### § 307(a)(1). The State

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### must provide such informationto the FLM atthe time that itprovides the FLM withnotice ofthe proposed new or modified source. 

### See, id. North Carolina's SIP-approvedNSRregulations instruct that this analysis shall be "provided by the source." 

### See 15A NCAC 02D.0530(q)(1) (EPA approval date Oct. 15, 1999) and 15A NCAC 02D.0531(i)(2) (EPA approval date Nov. 10, 1999).

Thank you for your willingness to work together with EPA and the FLM to ensure that the construction ofnew major sources ormajor modifications to existing sources will notresult in an adverse impact onvisibility in any Class I area. We are hopeful that improved communication amongst the three agencies regarding their expectations with respect to the protection ofvisibility and other air quality related values will avoid any future misunderstandings.

cc: Sandra Silva, Chief, Branch ofAir Quality, FWS Sincerely,

# ~~**JI~,~-t** Beverly H. Banister Director Air, Pesticides and Toxics

Management Division



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