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40 CFR Part 51, Subpart P: Protection of Visibility

§51.300 Purpose and applicability. 

 (a) Purpose. The primary purposes of this subpart are to require States to develop programs to 

assure reasonable progress toward meeting the national goal of preventing any future, and 

remedying any existing, impairment of visibility in mandatory Class I Federal areas which 

impairment results from manmade air pollution; and to establish necessary additional procedures 

for new source permit applicants, States and Federal Land Managers to use in conducting the 

visibility impact analysis required for new sources under §51.166. This subpart sets forth 

requirements addressing visibility impairment in its two principal forms: “reasonably 

attributable” impairment (i.e., impairment attributable to a single source/small group of sources) 

and regional haze (i.e., widespread haze from a multitude of sources which impairs visibility in 

every direction over a large area). 

(b) Applicability—The provisions of this subpart are applicable to all States as defined in section 

302(d) of the Clean Air Act (CAA) except Guam, Puerto Rico, American Samoa, and the 

Northern Mariana Islands. 

§51.301 Definitions. 

For purposes of this subpart: 

Adverse impact on visibility means, for purposes of section 307, visibility impairment which 

interferes with the management, protection, preservation, or enjoyment of the visitor's visual 

experience of the Federal Class I area. This determination must be made on a case-by-case basis 

taking into account the geographic extent, intensity, duration, frequency and time of visibility 

impairments, and how these factors correlate with (1) times of visitor use of the Federal Class I 

area, and (2) the frequency and timing of natural conditions that reduce visibility. This term does 

not include effects on integral vistas. 

Agency means the U.S. Environmental Protection Agency. 

BART-eligible source means an existing stationary facility as defined in this section. 

Best Available Retrofit Technology (BART) means an emission limitation based on the degree of 

reduction achievable through the application of the best system of continuous emission reduction 

for each pollutant which is emitted by an existing stationary facility. The emission limitation 

must be established, on a case-by-case basis, taking into consideration the technology available, 

the costs of compliance, the energy and nonair quality environmental impacts of compliance, any 

pollution control equipment in use or in existence at the source, the remaining useful life of the 

source, and the degree of improvement in visibility which may reasonably be anticipated to 

result from the use of such technology. 

Building, structure, or facility means all of the pollutant-emitting activities which belong to the 

same industrial grouping, are located on one or more contiguous or adjacent properties, and are 

under the control of the same person (or persons under common control). Pollutant-emitting 

activities must be considered as part of the same industrial grouping if they belong to the same 
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Major Group (i.e., which have the same two-digit code) as described in the Standard Industrial 

Classification Manual, 1972 as amended by the 1977 Supplement (U.S. Government Printing 

Office stock numbers 4101-0066 and 003-005-00176-0 respectively). 

Clearest days means the twenty percent of monitored days in a calendar year with the lowest 

values of the deciview index. 

Deciview is the unit of measurement on the deciview index scale for quantifying in a standard 

manner human perceptions of visibility. 

Deciview index means a value for a day that is derived from calculated or measured light 

extinction, such that uniform increments of the index correspond to uniform incremental changes 

in perception across the entire range of conditions, from pristine to very obscured. The deciview 

index is calculated based on the following equation (for the purposes of calculating deciview

using IMPROVE data, the atmospheric light extinction coefficient must be calculated from 

aerosol measurements and an estimate of Rayleigh scattering): 

Deciview index=10 lne (bext/10 Mm−1). 

bext=the atmospheric light extinction coefficient, expressed in inverse megameters (Mm−1). 

End of the applicable implementation period means December 31 of the year in which the next 

periodic comprehensive implementation plan revision is due under §51.308(f). 

Existing stationary facility means any of the following stationary sources of air pollutants, 

including any reconstructed source, which was not in operation prior to August 7, 1962, and was 

in existence on August 7, 1977, and has the potential to emit 250 tons per year or more of any air 

pollutant. In determining potential to emit, fugitive emissions, to the extent quantifiable, must be 

counted. 

Fossil-fuel fired steam electric plants of more than 250 million British thermal units per 

hour heat input, 

Coal cleaning plants (thermal dryers), 

Kraft pulp mills, 

Portland cement plants, 

Primary zinc smelters, 

Iron and steel mill plants, 

Primary aluminum ore reduction plants, 

Primary copper smelters, 

Municipal incinerators capable of charging more than 250 tons of refuse per day, 

Hydrofluoric, sulfuric, and nitric acid plants, 

Petroleum refineries, 

Lime plants, 

Phosphate rock processing plants, 

Coke oven batteries, 
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Sulfur recovery plants, 

Carbon black plants (furnace process), 

Primary lead smelters, 

Fuel conversion plants, 

Sintering plants, 

Secondary metal production facilities, 

Chemical process plants, 

Fossil-fuel boilers of more than 250 million British thermal units per hour heat input, 

Petroleum storage and transfer facilities with a capacity exceeding 300,000 barrels, 

Taconite ore processing facilities, 

Glass fiber processing plants, and 

Charcoal production facilities. 

Federal Class I area or Class I Federal area means any Federal land that is classified or 

reclassified Class I. Mandatory Federal Class I areas are identified in part 81, subpart D. Other 

Federal Class I areas are identified in part 52 of this title. 

Federal Land Manager means the Secretary of the department with authority over the Federal 

Class I area (or the Secretary's designee) or, with respect to Roosevelt-Campobello International 

Park, the Chairman of the Roosevelt-Campobello International Park Commission. 

Federally enforceable means all limitations and conditions which are enforceable by the 

Administrator under the Clean Air Act including those requirements developed pursuant to parts 

60 and 61 of this title, requirements within any applicable State Implementation Plan, and any 

permit requirements established pursuant to §52.21 of this chapter or under regulations approved 

pursuant to part 51, 52, or 60 of this title. 

Fixed capital cost means the capital needed to provide all of the depreciable components. 

Fugitive Emissions means those emissions which could not reasonably pass through a stack, 

chimney, vent, or other functionally equivalent opening. 

Geographic enhancement for the purpose of §51.308 means a method, procedure, or process to 

allow a broad regional strategy, such as an emissions trading program designed to achieve 

greater reasonable progress than BART for regional haze, to accommodate BART for reasonably 

attributable impairment. 

Implementation plan means, for the purposes of this part, any State Implementation Plan, Federal 

Implementation Plan, or Tribal Implementation Plan.

Indian tribe or tribe means any Indian tribe, band, nation, or other organized group or 

community, including any Alaska Native village, which is federally recognized as eligible for the 

special programs and services provided by the United States to Indians because of their status as 

Indians. 
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In existence means that the owner or operator has obtained all necessary preconstruction 

approvals or permits required by Federal, State, or local air pollution emissions and air quality 

laws or regulations and either has (1) begun, or caused to begin, a continuous program of 

physical on-site construction of the facility or (2) entered into binding agreements or contractual 

obligations, which cannot be cancelled or modified without substantial loss to the owner or 

operator, to undertake a program of construction of the facility to be completed in a reasonable 

time. 

In operation means engaged in activity related to the primary design function of the source. 

Installation means an identifiable piece of process equipment. 

Integral vista means 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. 

Least impaired days means the twenty percent of monitored days in a calendar year with the 

lowest amounts of visibility impairment. 

Major stationary source and major modification mean major stationary source and major 

modification, respectively, as defined in §51.166. 

Mandatory Class I Federal Area or Mandatory Federal Class I Area means any area identified 

in part 81, subpart D of this title. 

Most impaired days means the twenty percent of monitored days in a calendar year with the 

highest amounts of visibility impairment. 

Natural conditions includes naturally occurring phenomena that reduce visibility as measured in 

terms of light extinction, visual range, contrast, or coloration. 

Natural visibility conditions means visibility (light extinction, visual range, contrast, coloration, 

and texture) that would have existed under natural conditions. Natural visibility conditions vary 

with time and location, and are estimated or inferred rather than directly measured. 

Potential to emit means the maximum capacity of a stationary source to emit a pollutant under its 

physical and operational design. Any physical or operational limitation on the capacity of the 

source to emit a pollutant including air pollution control equipment and restrictions on hours of 

operation or on the type or amount of material combusted, stored, or processed, shall be treated 

as part of its design if the limitation or the effect it would have on emissions is federally 

enforceable. Secondary emissions do not count in determining the potential to emit of a 

stationary source.

Prescribed fire means any fire intentionally ignited by management actions in accordance with 

applicable laws, policies, and regulations to meet specific land or resource management 

objectives.

Reasonably attributable means attributable by visual observation or any other appropriate 

technique. 

Reasonably attributable visibility impairment means visibility impairment that is caused by the 

emission of air pollutants from one, or a small number of sources. 
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Reconstruction will be presumed to have taken place where the fixed capital cost of the new 

component exceeds 50 percent of the fixed capital cost of a comparable entirely new source. Any 

final decision as to whether reconstruction has occurred must be made in accordance with the 

provisions of §60.15 (f) (1) through (3) of this title. 

Regional haze means visibility impairment that is caused by the emission of air pollutants from 

numerous sources located over a wide geographic area. Such sources include, but are not limited 

to, major and minor stationary sources, mobile sources, and area sources. 

Secondary emissions means emissions which occur as a result of the construction or operation of 

an existing stationary facility but do not come from the existing stationary facility. Secondary 

emissions may include, but are not limited to, emissions from ships or trains coming to or from 

the existing stationary facility. 

Significant impairment means, for purposes of §51.303, visibility impairment which, in the 

judgment of the Administrator, interferes with the management, protection, preservation, or 

enjoyment of the visitor's visual experience of the mandatory Class I Federal area. This 

determination must be made on a case-by-case basis taking into account the geographic extent, 

intensity, duration, frequency and time of the visibility impairment, and how these factors 

correlate with (1) times of visitor use of the mandatory Class I Federal area, and (2) the 

frequency and timing of natural conditions that reduce visibility.

Smoke management program means a program in which users of prescribed fire are legally 

restricted from initiating a prescribed fire due to air quality concerns unless a government agency 

has authorized that action. 

State means “State” as defined in section 302(d) of the CAA. 

Stationary Source means any building, structure, facility, or installation which emits or may emit 

any air pollutant. 

Visibility means the degree of perceived clarity when viewing objects at a distance. Visibility 

includes perceived changes in depends on light extinction, visual range, contrast, or coloration, 

and texture elements in a scene. 

Visibility impairment means any humanly perceptible difference between actual visibility 

conditions and natural visibility conditions. Because natural visibility conditions can only be 

estimated or inferred, visibility impairment also is estimated or inferred rather than directly 

measured. 

Visibility in any mandatory Class I Federal area includes any integral vista associated with that 

area.

Wildfire means any fire started by an unplanned ignition caused by lightning; volcanoes; other 

acts of nature; unauthorized activity; or accidental, human-caused actions, or a prescribed fire 

that has been declared to be a wildfire. A wildfire that predominantly occurs on wildland is a 

natural event. 

Wildland means an area in which human activity and development is essentially non-existent, 

except for roads, railroads, power lines, and similar transportation facilities. Structures, if any, 

are widely scattered.
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§51.302 Reasonably attributable visibility impairment. 

(a) The affected Federal Land Manager may certify, at any time, that there exists reasonably 

attributable impairment of visibility in any mandatory Class I Federal area and identify which 

single source or small number of sources is responsible for such impairment. The affected 

Federal Land Manager will provide the certification to the State in which the impairment occurs 

and the State(s) in which the source(s) is located.

(b) The State(s) shall revise its regional haze implementation plan, in accordance with the 

schedules set forth in paragraphs (d)(1) and (d)(2) of this section, to include for each source or 

small number of sources that the Federal Land Manager has identified in whole or in part for 

reasonably attributable visibility impairment as part of a certification under paragraph (a) of this 

section: 

(1) A determination, based on the factors set forth in §51.308(d)(1)(i)(A), of the control 

measures, if any, that are necessary with respect to the source or sources in order for the plan to 

make reasonable progress toward natural visibility conditions in the affected Class I Federal 

area; 

(2) Emission limitations that reflect the degree of emission reduction achievable by such control 

measures and schedules for compliance as expeditiously as practicable; and 

(3) Monitoring, recordkeeping, and reporting requirements sufficient to ensure the enforceability 

of the emission limitations. 

(c) If a source that the Federal Land Manager has identified as responsible in whole or in part for 

reasonably attributable visibility impairment as part of a certification under paragraph (a) of this 

section is a BART-eligible source, and if there is not in effect as of the date of the certification a

fully or conditionally approved implementation plan addressing the BART requirement for that 

source (which existing plan may incorporate either source-specific emission limitations 

reflecting the emission control performance of BART, an alternative program to address the 

BART requirement under §51.308(e)(2), (3), and (4), or for sources of SO2 a program approved 

under paragraph §51.309(d)(4)), then the State shall revise its regional haze implementation plan 

to meet the requirements of §51.308(e) with respect to that source, taking into account current 

conditions related to the factors listed in §51.308(e)(1)(ii)(A). This requirement is in addition to 

the requirement of paragraph (b) of this section. 

(d)(1) For any existing reasonably attributable visibility impairment the Federal Land Manager 

certifies to the State(s) under paragraph (a) of this section more than 2 years prior to the due date 

for a regional haze implementation plan revision required under §51.308(f), the State(s) shall 

include the elements described in paragraphs (b) and (c) in such revision and such elements shall 

be considered a required part of such revision. 

(2) For any existing reasonably attributable visibility impairment the Federal Land Manager 

certifies to the State(s) under paragraph (a) of this section less than 2 years prior to the due date 

for a regional haze implementation plan revision required under §51.308(f), but no more than 6 

months subsequent to that due datethe submission date of that implementation plan revision or 

no more than 6 months subsequent to a further plan revision that changes the emission limitation 
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for the subject source, the State(s) shall submit a revision to its regional haze implementation 

plan that includes the elements described in paragraph (b) and (c) no later than 2 years after the 

date of the certification. The State(s) is not required at that time to also revise its reasonable 

progress goals to reflect the additional emission reductions required from the source or sources. 

§51.303 Exemptions from control. 

(a)(1) Any existing stationary facility subject to the requirement under §51.302 to install, 

operate, and maintain BART may apply to the Administrator for an exemption from that 

requirement. 

(2) An application under this section must include all available documentation relevant to the 

impact of the source's emissions on visibility in any mandatory Class I Federal area and a 

demonstration by the existing stationary facility that it does not or will not, by itself or in 

combination with other sources, emit any air pollutant which may be reasonably anticipated to 

cause or contribute to a significant impairment of visibility in any mandatory Class I Federal 

area. 

(b) Any fossil-fuel fired power plant with a total generating capacity of 750 megawatts or more 

may receive an exemption from BART only if the owner or operator of such power plant 

demonstrates to the satisfaction of the Administrator that such power plant is located at such a 

distance from all mandatory Class I Federal areas that such power plant does not or will not, by 

itself or in combination with other sources, emit any air pollutant which may reasonably be 

anticipated to cause or contribute to significant impairment of visibility in any such mandatory 

Class I Federal area. 

(c) Application under this §51.303 must be accompanied by a written concurrence from the State 

with regulatory authority over the source. 

(d) The existing stationary facility must give prior written notice to all affected Federal Land 

Managers of any application for exemption under this §51.303. 

(e) The Federal Land Manager may provide an initial recommendation or comment on the 

disposition of such application. Such recommendation, where provided, must be part of the 

exemption application. This recommendation is not to be construed as the concurrence required 

under paragraph (h) of this section. 

(f) The Administrator, within 90 days of receipt of an application for exemption from control, 

will provide notice of receipt of an exemption application and notice of opportunity for public 

hearing on the application. 

(g) After notice and opportunity for public hearing, the Administrator may grant or deny the 

exemption. For purposes of judicial review, final EPA action on an application for an exemption 

under this §51.303 will not occur until EPA approves or disapproves the State Implementation 

Plan revision. 

(h) An exemption granted by the Administrator under this §51.303 will be effective only upon 

concurrence by all affected Federal Land Managers with the Administrator's determination. 
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§51.304 Identification of integral vistas. 

 (a) Federal Land Managers were required to identify any integral vistas on or before December 

31, 1985, according to criteria the Federal Land Managers developed. These criteria must have 

included, but were not limited to, whether the integral vista was important to the visitor's visual 

experience of the mandatory Class I Federal area. 

(b) The following integral vistas were identified by Federal Land Managers: at Roosevelt 

Campobello International Park, from the observation point of Roosevelt cottage and beach area, 

the viewing angle from 244 to 256 degrees; and at Roosevelt Campobello International Park, 

from the observation point of Friar’s Head, the viewing angle from 154 to 194 degrees. 

(c) The State must list in its implementation plan any integral vista listed in paragraph (b) of this 

section. 

§51.305 Monitoring for reasonably attributable visibility impairment. 

For the purposes of addressing reasonably attributable visibility impairment, if the 

Administrator, Regional Administrator, or the affected Federal Land Manager has advised a 

State containing a mandatory Class I Federal area of a need for monitoring to assess reasonably 

attributable visibility impairment at a mandatory Class I Federal area in addition to the 

monitoring currently being conducted to meet the requirements of §51.308(d)(4), the State must 

include in the next implementation plan revision to meet the requirement of §51.308(f) an 

appropriate strategy for evaluating reasonably attributable visibility impairment in the mandatory 

Class I Federal area by visual observation or other appropriate monitoring techniques. Such 

strategy must take into account current and anticipated visibility monitoring research, the 

availability of appropriate monitoring techniques, and such guidance as is provided by the 

Agency. 

§51.306 [Reserved] 

§51.307 New source review. 

 (a) For purposes of new source review of any new major stationary source or major modification 

that would be constructed in an area that is designated attainment or unclassified under section 

107(d) of the CAA, the State plan must, in any review under §51.166 with respect to visibility 

protection and analyses, provide for: 

(1) Written notification of all affected Federal Land Managers of any proposed new major 

stationary source or major modification that may affect visibility in any Federal Class I area. 

Such notification must be made in writing and include a copy of all information relevant to the 

permit application within 30 days of receipt of and at least 60 days prior to public hearing by the 
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State on the application for permit to construct. Such notification must include an analysis of the 

anticipated impacts on visibility in any Federal Class I area, 

(2) Where the State requires or receives advance notification (e.g. early consultation with the 

source prior to submission of the application or notification of intent to monitor under §51.166) 

of a permit application of a source that may affect visibility the State must notify all affected 

Federal Land Managers within 30 days of such advance notification, and 

(3) Consideration of any analysis performed by the Federal Land Manager, provided within 30 

days of the notification and analysis required by paragraph (a)(1) of this section, that such 

proposed new major stationary source or major modification may have an adverse impact on 

visibility in any Federal Class I area. Where the State finds that such an analysis does not 

demonstrate to the satisfaction of the State that an adverse impact will result in the Federal Class 

I area, the State must, in the notice of public hearing, either explain its decision or give notice as

to where the explanation can be obtained. 

(b) The plan shall also provide for the review of any new major stationary source or major 

modification: 

(1) That may have an impact on any integral vista of a mandatory Class I Federal area listed in 

§51.304(b), or 

(2) That proposes to locate in an area classified as nonattainment under section 107(d)(1) of the 

Clean Air Act that may have an impact on visibility in any mandatory Class I Federal area. 

(c) Review of any major stationary source or major modification under paragraph (b) of this 

section, shall be conducted in accordance with paragraph (a) of this section, and §51.166(o), 

(p)(1) through (2), and (q). In conducting such reviews the State must ensure that the source's 

emissions will be consistent with making reasonable progress toward the national visibility goal 

referred to in §51.300(a). The State may take into account the costs of compliance, the time 

necessary for compliance, the energy and nonair quality environmental impacts of compliance, 

and the useful life of the source. 

(d) The State may require monitoring of visibility in any Federal Class I area near the proposed 

new stationary source or major modification for such purposes and by such means as the State 

deems necessary and appropriate. 

§51.308 Regional haze program requirements. 

 (a) What is the purpose of this section? This section establishes requirements for implementation 

plans, plan revisions, and periodic progress reviews to address regional haze. 

(b) When are the first implementation plans due under the regional haze program? Except as 

provided in §51.309(c), each State identified in §51.300(b) must submit, for the entire State, an 

implementation plan for regional haze meeting the requirements of paragraphs (d) and (e) of this 

section no later than December 17, 2007. 

(c) What is the relationship between requirements for regional haze and requirements for 

reasonably attributable visibility impairment? A State must address any reasonably attributable 

visibility impairment certified by a Federal Land Manager under §51.302(a) in its regional haze 
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implementation plan, as required by §51.302(b)-(d). A State must also meet the requirements of 

§51.305 if the Administrator, Regional Administrator, or the Federal Land Manager has advised 

a State under §51.305 of a need for additional monitoring to assess reasonably attributable 

visibility impairment at a mandatory Class I Federal area. 

(d) What are the core requirements for the implementation plan for regional haze? The State 

must address regional haze in each mandatory Class I Federal area located within the State and in 

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

emissions from within the State. To meet the core requirements for regional haze for these areas, 

the State must submit an implementation plan containing the following plan elements and 

supporting documentation for all required analyses:

(1) Reasonable progress goals. 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. 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. 

(i) In establishing a reasonable progress goal for any mandatory Class I Federal area within the 

State, the State must: 

(A) Consider the costs of compliance, the time necessary for compliance, the energy and non-air 

quality environmental impacts of compliance, and the remaining useful life of any potentially 

affected sources, and include a demonstration showing how these factors were taken into 

consideration in selecting the goal. 

(B) Analyze and determine the rate of progress needed to attain natural visibility conditions by 

the year 2064. To calculate this rate of progress, the State must compare baseline visibility 

conditions to natural visibility conditions in the mandatory Federal Class I area 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. In establishing the reasonable progress goal, the State must consider the uniform rate of 

improvement in visibility and the emission reduction measures needed to achieve it for the 

period covered by the implementation plan. 

(ii) For the period of the implementation plan, if the State establishes a reasonable progress goal 

that provides for a slower rate of improvement in visibility than the rate that would be needed to 

attain natural conditions by 2064, the State must demonstrate, based on the factors in paragraph 

(d)(1)(i)(A) of this section, that the rate of progress for the implementation plan to attain natural 

conditions by 2064 is not reasonable; and that the progress goal adopted by the State is 

reasonable. The State must provide to the public for review as part of its implementation plan an 

assessment of the number of years it would take to attain natural conditions if visibility 

improvement continues at the rate of progress selected by the State as reasonable. 

(iii) In determining whether the State's goal for visibility improvement provides for reasonable 

progress towards natural visibility conditions, the Administrator will evaluate the demonstrations 

developed by the State pursuant to paragraphs (d)(1)(i) and (d)(1)(ii) of this section. 
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(iv) In developing each reasonable progress goal, the State must consult with those States which 

may reasonably be anticipated to cause or contribute to visibility impairment in the mandatory 

Class I Federal area. In any situation in which the State cannot agree with another such State or 

group of States that a goal provides for reasonable progress, the State must describe in its 

submittal the actions taken to resolve the disagreement. In reviewing the State's implementation 

plan submittal, the Administrator will take this information into account in determining whether 

the State's goal for visibility improvement provides for reasonable progress towards natural 

visibility conditions. 

(v) The reasonable progress goals established by the State are not directly enforceable but will be 

considered by the Administrator in evaluating the adequacy of the measures in the 

implementation plan to achieve the progress goal adopted by the State. 

(vi) The State may not adopt a reasonable progress goal that represents less visibility 

improvement than is expected to result from implementation of other requirements of the CAA 

during the applicable planning period. 

(2) Calculations of baseline and natural visibility conditions. For each mandatory Class I Federal 

area located within the State, the State must determine the following visibility conditions 

(expressed in deciviews): 

(i) Baseline visibility conditions for the most impaired and least impaired days. The period for 

establishing baseline visibility conditions is 2000 to 2004. Baseline visibility conditions must be 

calculated, using available monitoring data, by establishing the average degree of visibility 

impairment for the most and least impaired days for each calendar year from 2000 to 2004. The 

baseline visibility conditions are the average of these annual values. For mandatory Class I 

Federal areas without onsite monitoring data for 2000-2004, the State must establish baseline 

values using the most representative available monitoring data for 2000-2004, in consultation 

with the Administrator or his or her designee; 

(ii) For an implementation plan that is submitted by 2003, the period for establishing baseline 

visibility conditions for the period of the first long-term strategy is the most recent 5-year period 

for which visibility monitoring data are available for the mandatory Class I Federal areas 

addressed by the plan. For mandatory Class I Federal areas without onsite monitoring data, the 

State must establish baseline values using the most representative available monitoring data, in 

consultation with the Administrator or his or her designee; 

(iii) Natural visibility conditions for the most impaired and least impaired days. 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; and 

(iv) For the first implementation plan addressing the requirements of paragraphs (d) and (e) of 

this section, the number of deciviews by which baseline conditions exceed natural visibility 

conditions for the most impaired and least impaired days. 

 (3) Long-term strategy for regional haze. Each State listed in §51.300(b) must submit a longterm strategy that addresses regional haze visibility impairment for each mandatory Class I 

Federal area within the State and for each mandatory Class I Federal area located outside the 
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State that may be affected by emissions from the State. The long-term strategy must include 

enforceable emissions limitations, compliance schedules, and other measures as necessary to 

achieve the reasonable progress goals established by States having mandatory Class I Federal 

areas. In establishing its long-term strategy for regional haze, the State must meet the following 

requirements: 

(i) Where the State has emissions that are reasonably anticipated to contribute to visibility 

impairment in any mandatory Class I Federal area located in another State or States, the State 

must consult with the other State(s) in order to develop coordinated emission management 

strategies. The State must consult with any other State having emissions that are reasonably 

anticipated to contribute to visibility impairment in any mandatory Class I Federal area within 

the State. 

(ii) Where other States cause or contribute to impairment in a mandatory Class I Federal area, the 

State must demonstrate that it has included in its implementation plan all measures necessary to 

obtain its share of the emission reductions needed to meet the progress goal for the area. If the 

State has participated in a regional planning process, the State must ensure it has included all 

measures needed to achieve its apportionment of emission reduction obligations agreed upon 

through that process. 

(iii) The State 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. The State must identify the 

baseline emissions inventory on which its strategies are based. The baseline emissions inventory 

year is presumed to be the most recent year of the consolidate periodic emissions inventory. 

(iv) 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. 

(v) 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; 

(F) Enforceability of emissions limitations and control measures; and 

(G) The anticipated net effect on visibility due to projected changes in point, area, and mobile 

source emissions over the period addressed by the long-term strategy. 
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(4) Monitoring strategy and other implementation plan requirements. The State must submit 

with the implementation plan 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. This monitoring strategy must be coordinated with the monitoring strategy 

required in §51.305 for reasonably attributable visibility impairment. Compliance with this 

requirement may be met through participation in the Interagency Monitoring of Protected Visual 

Environments network. The implementation plan must also provide for the following: 

(i) 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. 

(ii) 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. 

(iii) For a State with no mandatory Class I Federal areas, 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 in other States. 

(iv) The implementation plan must provide for the reporting of all visibility monitoring data to 

the Administrator at least annually for each mandatory Class I Federal area in the State. To the 

extent possible, the State should report visibility monitoring data electronically. 

(v) 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. 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. The State must also include a commitment 

to update the inventory periodically. 

(vi) Other elements, including reporting, recordkeeping, and other measures, necessary to assess 

and report on visibility. 

(e) Best Available Retrofit Technology (BART) requirements for regional haze visibility 

impairment. The State must submit an implementation plan containing emission limitations 

representing BART and schedules for compliance with BART for each BART-eligible source 

that may reasonably be anticipated to cause or contribute to any impairment of visibility in any 

mandatory Class I Federal area, unless the State demonstrates that an emissions trading program 

or other alternative will achieve greater reasonable progress toward natural visibility conditions. 

(1) To address the requirements for BART, the State must submit an implementation plan 

containing the following plan elements and include documentation for all required analyses: 

(i) A list of all BART-eligible sources within the State. 

(ii) A determination of BART for each BART-eligible source in the State that emits any air 

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

visibility in any mandatory Class I Federal area. All such sources are subject to BART. 

(A) The determination of BART must be based on an analysis of the best system of continuous 

emission control technology available and associated emission reductions achievable for each 
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14 

BART-eligible source that is subject to BART within the State. In this analysis, the State must 

take into consideration the technology available, the costs of compliance, the energy and nonair 

quality environmental impacts of compliance, any pollution control equipment in use at the 

source, the remaining useful life of the source, and the degree of improvement in visibility which 

may reasonably be anticipated to result from the use of such technology. 

(B) The determination of BART for fossil-fuel fired power plants having a total generating 

capacity greater than 750 megawatts must be made pursuant to the guidelines in appendix Y of 

this part (Guidelines for BART Determinations Under the Regional Haze Rule). 

(C) Exception. A State is not required to make a determination of BART for SO2 or for NOX if a 

BART-eligible source has the potential to emit less than 40 tons per year of such pollutant(s), or 

for PM10 if a BART-eligible source has the potential to emit less than 15 tons per year of such 

pollutant. 

(iii) If the State determines in establishing BART that technological or economic limitations on 

the applicability of measurement methodology to a particular source would make the imposition 

of an emission standard infeasible, it may instead prescribe a design, equipment, work practice, 

or other operational standard, or combination thereof, to require the application of BART. Such 

standard, to the degree possible, is to set forth the emission reduction to be achieved by 

implementation of such design, equipment, work practice or operation, and must provide for 

compliance by means which achieve equivalent results. 

(iv) 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 5 years after approval of the 

implementation plan revision. 

(v) A requirement that each source subject to BART maintain the control equipment required by 

this subpart and establish procedures to ensure such equipment is properly operated and 

maintained. 

(2) A State may opt to implement or require participation in an emissions trading program or 

other alternative measure rather than to require sources subject to BART to install, operate, and 

maintain BART. Such an emissions trading program or other alternative measure must achieve 

greater reasonable progress than would be achieved through the installation and operation of 

BART. For all such emission trading programs or other alternative measures, the State must 

submit an implementation plan containing the following plan elements and include 

documentation for all required analyses: 

(i) A demonstration that the emissions trading program or other alternative measure will achieve 

greater reasonable progress than would have resulted from the installation and operation of 

BART at all sources subject to BART in the State and covered by the alternative program. This 

demonstration must be based on the following: 

(A) A list of all BART-eligible sources within the State. 

(B) A list of all BART-eligible sources and all BART source categories covered by the 

alternative program. The State is not required to include every BART source category or every 

BART-eligible source within a BART source category in an alternative program, but each 
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BART-eligible source in the State must be subject to the requirements of the alternative program, 

have a federally enforceable emission limitation determined by the State and approved by EPA 

as meeting BART in accordance with section 302(c) or paragraph (e)(1) of this section, or 

otherwise addressed under paragraphs (e)(1) or (e)(4)of this section. 

(C) An analysis of the best system of continuous emission control technology available and 

associated emission reductions achievable for each source within the State subject to BART and 

covered by the alternative program. This analysis must be conducted by making a determination 

of BART for each source subject to BART and covered by the alternative program as provided 

for in paragraph (e)(1) of this section, unless the emissions trading program or other alternative 

measure has been designed to meet a requirement other than BART (such as the core 

requirement to have a long-term strategy to achieve the reasonable progress goals established by 

States). In this case, the State may determine the best system of continuous emission control 

technology and associated emission reductions for similar types of sources within a source 

category based on both source-specific and category-wide information, as appropriate. 

(D) An analysis of the projected emissions reductions achievable through the trading program or 

other alternative measure. 

(E) A determination under paragraph (e)(3) of this section or otherwise based on the clear weight 

of evidence that the trading program or other alternative measure achieves greater reasonable 

progress than would be achieved through the installation and operation of BART at the covered 

sources. 

(ii) [Reserved] 

(iii) A requirement that all necessary emission reductions take place during the period of the first 

long-term strategy for regional haze. To meet this requirement, the State must provide a detailed 

description of the emissions trading program or other alternative measure, including schedules 

for implementation, the emission reductions required by the program, all necessary 

administrative and technical procedures for implementing the program, rules for accounting and 

monitoring emissions, and procedures for enforcement. 

(iv) A demonstration that the emission reductions resulting from the emissions trading program 

or other alternative measure will be surplus to those reductions resulting from measures adopted 

to meet requirements of the CAA as of the baseline date of the SIP. 

(v) At the State's option, a provision that the emissions trading program or other alternative 

measure may include a geographic enhancement to the program to address the requirement under 

§51.302(b) related to reasonably attributable impairment from the pollutants covered under the 

emissions trading program or other alternative measure. 

(vi) For plans that include an emissions trading program that establishes a cap on total annual 

emissions of SO2 or NOX from sources subject to the program, requires the owners and operators 

of sources to hold allowances or authorizations to emit equal to emissions, and allows the owners 

and operators of sources and other entities to purchase, sell, and transfer allowances, the 

following elements are required concerning the emissions covered by the cap: 
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(A) Applicability provisions defining the sources subject to the program. The State must 

demonstrate that the applicability provisions (including the size criteria for including sources in 

the program) are designed to prevent any significant potential shifting within the State of 

production and emissions from sources in the program to sources outside the program. In the 

case of a program covering sources in multiple States, the States must demonstrate that the 

applicability provisions in each State cover essentially the same size facilities and, if source 

categories are specified, cover the same source categories and prevent any significant, potential 

shifting within such States of production and emissions to sources outside the program. 

(B) Allowance provisions ensuring that the total value of allowances (in tons) issued each year 

under the program will not exceed the emissions cap (in tons) on total annual emissions from the 

sources in the program. 

(C) Monitoring provisions providing for consistent and accurate measurements of emissions 

from sources in the program to ensure that each allowance actually represents the same specified 

tonnage of emissions and that emissions are measured with similar accuracy at all sources in the 

program. The monitoring provisions must require that boilers, combustion turbines, and cement 

kilns in the program allowed to sell or transfer allowances must comply with the requirements of 

part 75 of this chapter. The monitoring provisions must require that other sources in the program 

allowed to sell or transfer allowances must provide emissions information with the same 

precision, reliability, accessibility, and timeliness as information provided under part 75 of this 

chapter. 

(D) Recordkeeping provisions that ensure the enforceability of the emissions monitoring 

provisions and other program requirements. The recordkeeping provisions must require that 

boilers, combustion turbines, and cement kilns in the program allowed to sell or transfer 

allowances must comply with the recordkeeping provisions of part 75 of this chapter. The 

recordkeeping provisions must require that other sources in the program allowed to sell or 

transfer allowances must comply with recordkeeping requirements that, as compared with the 

recordkeeping provisions under part 75 of this chapter, are of comparable stringency and require 

recording of comparable types of information and retention of the records for comparable 

periods of time. 

(E) Reporting provisions requiring timely reporting of monitoring data with sufficient frequency 

to ensure the enforceability of the emissions monitoring provisions and other program 

requirements and the ability to audit the program. The reporting provisions must require that 

boilers, combustion turbines, and cement kilns in the program allowed to sell or transfer 

allowances must comply with the reporting provisions of part 75 of this chapter, except that, if 

the Administrator is not the tracking system administrator for the program, emissions may be 

reported to the tracking system administrator, rather than to the Administrator. The reporting 

provisions must require that other sources in the program allowed to sell or transfer allowances 

must comply with reporting requirements that, as compared with the reporting provisions under 

part 75 of this chapter, are of comparable stringency and require reporting of comparable types 

of information and require comparable timeliness and frequency of reporting. 
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17 

(F) Tracking system provisions which provide for a tracking system that is publicly available in a 

secure, centralized database to track in a consistent manner all allowances and emissions in the 

program. 

(G) Authorized account representative provisions ensuring that the owners and operators of a 

source designate one individual who is authorized to represent the owners and operators in all 

matters pertaining to the trading program. 

(H) Allowance transfer provisions providing procedures that allow timely transfer and recording 

of allowances, minimize administrative barriers to the operation of the allowance market, and 

ensure that such procedures apply uniformly to all sources and other potential participants in the 

allowance market. 

(I) Compliance provisions prohibiting a source from emitting a total tonnage of a pollutant that 

exceeds the tonnage value of its allowance holdings, including the methods and procedures for 

determining whether emissions exceed allowance holdings. Such method and procedures shall 

apply consistently from source to source. 

(J) Penalty provisions providing for mandatory allowance deductions for excess emissions that 

apply consistently from source to source. The tonnage value of the allowances deducted shall 

equal at least three times the tonnage of the excess emissions. 

(K) For a trading program that allows banking of allowances, provisions clarifying any 

restrictions on the use of these banked allowances.

(L) Program assessment provisions providing for periodic program evaluation to assess whether 

the program is accomplishing its goals and whether modifications to the program are needed to 

enhance performance of the program. 

(3) A State which opts under 40 CFR 51.308(e)(2) to implement an emissions trading program or 

other alternative measure rather than to require sources subject to BART to install, operate, and 

maintain BART may satisfy the final step of the demonstration required by that section as 

follows: If the distribution of emissions is not substantially different than under BART, and the 

alternative measure results in greater emission reductions, then the alternative measure may be 

deemed to achieve greater reasonable progress. If the distribution of emissions is significantly 

different, the State must conduct dispersion modeling to determine differences in visibility 

between BART and the trading program for each impacted Class I area, for the worst and best 20 

percent of days. The modeling would demonstrate “greater reasonable progress” if both of the 

following two criteria are met: 

(i) Visibility does not decline in any Class I area, and 

(ii) There is an overall improvement in visibility, determined by comparing the average 

differences between BART and the alternative over all affected Class I areas. 

(4) A State subject to a trading program established in accordance with §52.38 or §52.39 under a 

Transport Rule Federal Implementation Plan need not require BART-eligible fossil fuel-fired 

steam electric plants in the State to install, operate, and maintain BART for the pollutant covered 

by such trading program in the State. A State that chooses to meet the emission reduction 

requirements of the Transport Rule by submitting a SIP revision that establishes a trading 
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18 

program and is approved as meeting the requirements of §52.38 or §52.39 also need not require 

BART-eligible fossil fuel-fired steam electric plants in the State to install, operate, and maintain 

BART for the pollutant covered by such trading program in the State. A State may adopt 

provisions, consistent with the requirements applicable to the State for a trading program 

established in accordance with §52.38 or §52.39 under the Transport Rule Federal 

Implementation Plan or established under a SIP revision that is approved as meeting the 

requirements of §52.38 or §52.39, for a geographic enhancement to the program to address any 

requirement under §51.302(b) related to reasonably attributable impairment from the pollutant 

covered by such trading program in that State. 

(5) After a State has met the requirements for BART or implemented emissions trading program 

or other alternative measure that achieves more reasonable progress than the installation and 

operation of BART, BART-eligible sources will be subject to the requirements of paragraphs (d) 

and (f) of this section, as applicable, in the same manner as other sources. 

(6) Any BART-eligible facility subject to the requirement under paragraph (e) of this section to 

install, operate, and maintain BART may apply to the Administrator for an exemption from that 

requirement. An application for an exemption will be subject to the requirements of 

§51.303(a)(2)-(h). 

(f) Requirements for periodic comprehensive revisions of implementation plans for regional 

haze. Each State identified in §51.300(b) must revise and submit its regional haze 

implementation plan revision to EPA by July 31, 2021, July 31, 2028, and every 10 years 

thereafter. The plan revision due on or before July 31, 2021 must include a commitment by the 

State to meet the requirements of paragraph (g). In each plan revision, the State must address 

regional haze in 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. To meet the core requirements for regional haze for these areas, the State must 

submit an implementation plan containing the following plan elements and supporting 

documentation for all required analyses: 

(1) Calculations of baseline, current, and natural visibility conditions; progress to date; and the 

uniform rate of progress. For each mandatory Class I Federal area located within the State, the 

State must determine the following: 

(i) Baseline visibility conditions for the most impaired and clearest days. The period for 

establishing baseline visibility conditions is 2000 to 2004. For purposes of calculating and 

displaying the uniform rate of progress needed to attain natural visibility conditions by the end of 

2064, baseline visibility conditions must be associated with the last day of this period. Baseline 

visibility conditions must be calculated, using available monitoring data, by establishing the 

average deciview index for the most impaired and clearest days for each calendar year from 2000 

to 2004. The baseline visibility conditions are the average of these annual values. For mandatory 

Class I Federal areas without onsite monitoring data for 2000-2004, the State must establish 

baseline values using the most representative available monitoring data for 2000-2004, in 

consultation with the Administrator or his or her designee. For mandatory Class I Federal areas 

with incomplete data availability for 2000-2004, the State must establish baseline values using 

the closest 5 complete years of monitoring data.
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(ii) Natural visibility conditions for the most impaired and clearest days. Natural visibility 

conditions must be calculated by estimating the deciview index existing under natural conditions 

for the most impaired and clearest days, based on available monitoring information and 

appropriate data analysis techniques; and 

(iii) Current visibility conditions for the most impaired and clearest days. The period for 

calculating current visibility conditions is the most recent 5-year period for which data are 

available. Current visibility conditions must be calculated based on the annual average level of 

visibility impairment for the most impaired and clearest days for each of these 5 years. Current 

visibility conditions are the average of these annual values. 

(iv) Progress to date for the most impaired and clearest days. Actual progress made towards 

natural conditions since the baseline period, and actual progress made during the previous 

implementation period up to and including to the period for calculating current visibility 

conditions, for the most impaired and clearest days, must be calculated. 

(v) Difference between current visibility conditions and natural visibility conditions. The number 

of deciviews by which current visibility conditions exceed natural visibility conditions, for the 

most impaired and clearest days, must be calculated. 

(vi) Uniform rate of progress. The uniform rate of progress needed to attain natural visibility 

conditions by the end of 2064 for each mandatory Class I Federal area in the State must be 

calculated. To calculate this uniform rate of progress, the State must compare baseline visibility 

conditions to natural visibility conditions in the mandatory Class I Federal area and determine 

the uniform rate of visibility improvement (measured in deciviews of improvement per year) that 

would need to be maintained during each implementation period in order to attain natural 

visibility conditions by the end of 2064. 

(2) Long-term strategy for regional haze and reasonably attributable visibility impairment. Each 

State must submit a long-term strategy that addresses regional haze visibility impairment, and if 

necessary any reasonably attributable visibility impairment certified by the Federal Land 

Manager under §51.302(a), for each mandatory Class I Federal area within the State and for each 

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

the State. The long-term strategy must include the enforceable emissions limitations, compliance 

schedules, and other measures that are necessary to achieve reasonable progress, as determined 

pursuant to (f)(2)(i) through (vi). In establishing its long-term strategy for regional haze, the 

State must meet the following requirements: 

(i) The State must consider and analyze emission reduction measures based on the costs of 

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

impacts of compliance, and the remaining useful life of any potentially affected major or minor 

stationary source or group of sources. The State must document the criteria used to determine 

which sources or groups of sources were evaluated, and how these four factors were taken into 

consideration in selecting the measures for inclusion in its long-term strategy. 

(ii) The State must consider the uniform rate of improvement in visibility, the emission reduction 

measures identified in (f)(2)(i), and additional measures being adopted by other contributing 
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20 

states in (f)(2)(iii) as needed to make reasonable progress towards natural visibility conditions 

for the period covered by the implementation plan. 

(iii) The State must consult with those States which may reasonably be anticipated to cause or 

contribute to visibility impairment in the mandatory Class I Federal area. 

(A) Contributing States. Where the State has emissions that are reasonably anticipated to 

contribute to visibility impairment in any mandatory Class I Federal area located in another State 

or States, the State must consult with the other State(s) in order to develop coordinated emission 

management strategies. The State must demonstrate that it has included in its implementation 

plan all measures necessary to obtain its share of the emission reductions needed to provide for 

reasonable progress towards natural visibility conditions in the mandatory Class I Federal area 

located in the other State or States. If the State has participated in a regional planning process, 

the State must also ensure that it has included all measures needed to achieve its apportionment 

of emission reduction obligations agreed upon through that process. 

(B) States affected by contributing States. A State with a mandatory Class I Federal area must 

consult with any other State having emissions that are reasonably anticipated to contribute to 

visibility impairment in that area regarding the emission reductions needed in each State to 

provide for reasonable progress towards natural visibility conditions in that area. If the State has 

participated in a regional planning process, the State must ensure it has included all measures 

needed to achieve its apportionment of emission reduction obligations agreed upon through that 

process. 

(C) In any situation in which a State cannot agree with another State or group of States on the 

emission reductions needed for reasonable progress towards natural visibility conditions in any 

mandatory Class I Federal area, each involved State must describe in its submittal the actions 

taken to resolve the disagreement. In reviewing the State's implementation plan submittal, the 

Administrator will take this information into account in determining whether the State's 

implementation plan provides for reasonable progress towards natural visibility conditions at 

each mandatory Class I Federal area that is located in the State or that may be affected by 

emissions from the State. All substantive interstate consultations must be documented. 

(iv) As part of the demonstration required by (f)(2)(i), the State must document the technical 

basis, including information on the factors listed in (f)(2)(i) and modeling, monitoring, and 

emissions information, on which the State is relying to determine the emission reductions from 

anthropogenic sources in the State that are necessary for achieving reasonable progress towards 

natural visibility conditions in each mandatory Class I Federal area it affects. The State may meet 

this requirement by relying on technical analyses developed by a regional planning process and 

approved by all State participants. The State must identify the baseline emissions inventory on 

which its strategies are based. The baseline emissions inventory year shall be the most recent 

year for which the State has submitted emission inventory information to the Administrator in 

compliance with the triennial reporting requirements of subpart A of this part unless the State 

adequately justifies the use of another inventory year. 
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21 

(v) The State must identify all anthropogenic sources of visibility impairment considered by the 

State in developing its long-term strategy and the criteria used to select the sources considered. 

The State should consider major and minor stationary sources, mobile sources, and area sources. 

(vi) 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 Basic smoke management practices for prescribed fire used 

for agricultural and forestry management purposes and smoke management programs including 

plans as currently exist as currently exist within the State for these purposes; 

(F) Enforceability of emissions limitations and control measures; and 

(G) The anticipated net effect on visibility due to projected changes in point, area, and mobile 

source emissions over the period addressed by the long-term strategy. 

(3) Reasonable progress goals. (i) A state in which a mandatory Class I Federal area is located 

must establish reasonable progress goals (expressed in deciviews) that reflect the visibility 

conditions that are projected to be achieved by the end of the applicable implementation period 

as a result of all enforceable emissions limitations, compliance schedules, and other measures 

required under paragraph (f)(2) and the implementation of other requirements of the CAA. The 

long-term strategy and the reasonable progress goals must provide for an improvement in 

visibility for the most impaired days and ensure no degradation in visibility for the clearest days.

(ii)(A) If a State in which a mandatory Class I Federal area is located establishes a reasonable 

progress goal for the most impaired days that provides for a slower rate of improvement in 

visibility than the uniform rate of progress calculated under paragraph (f)(1)(vi) of this section, 

the State must demonstrate, based on the analysis required by paragraph (f)(2)(i) of this section, 

that there are no additional emission reduction measures for anthropogenic sources or groups of 

sources in the State that may reasonably be anticipated to contribute to visibility impairment in 

the Class I area that would be reasonable to include in the long-term strategy. The State must 

provide a robust demonstration, including documenting the criteria used to determine which 

sources or groups or sources were evaluated and how the four factors required by paragraph 

(f)(2)(i) were taken into consideration in selecting the measures for inclusion in its long-term 

strategy. The State must provide to the public for review as part of its implementation plan an 

assessment of the number of years it would take to attain natural visibility conditions if visibility 

improvement were to continue at the rate of progress selected by the State as reasonable for the 

implementation period. 
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(B) If a State contains sources which are reasonably anticipated to contribute to visibility 

impairment in a mandatory Class I Federal area in another State for which a demonstration by 

the other State is required under (f)(3)(ii)(A), the State must make the same demonstrateion that 

there are no additional emission reduction measures for anthropogenic sources or groups of 

sources in the State that may reasonably be anticipated to contribute to visibility impairment in 

the Class I area that would be reasonable to include in with respect to its own long-term strategy. 

 (iii) The reasonable progress goals established by the State are not directly enforceable but will 

be considered by the Administrator in evaluating the adequacy of the measures in the 

implementation plan in providing for reasonable progress towards achieving natural visibility 

conditions at that area. 

(iv) In determining whether the State’s goal for visibility improvement provides for reasonable 

progress towards natural visibility conditions, the Administrator will also evaluate the 

demonstrations developed by the State pursuant to paragraphs (f)(2) and (f)(3)(ii)(A) of this 

section and the demonstrations provided by other States pursuant to paragraphs (f)(2) and 

(f)(3)(ii)(B) of this section.

(v) A State with a Class I area, or a State that has emissions that are reasonably anticipated to 

contribute to visibility impairment in a Class I area in another State, may include in its plan an 

assessment of impacts on current and future visibility conditions at the Class I area from 

international anthropogenic emissions, including information on the magnitude and temporal 

pattern of impacts from such emissions, and may propose adjustments to the value of the 

reasonable progress goal and/or the uniform rate of progress for application as part of the 

comparison between the reasonable progress goal and the uniform rate of progress required by 

paragraph (f)(3)(ii). The intended purpose of the adjustments is to remove the effect of 

international anthropogenic emissions from the determination of whether the plan provides 

progress equal to the uniform rate of progress. If the State has estimated international impacts 

and calculated the adjustments with methods and data that the Administrator determines are 

sufficiently reliable for the intended purpose of the adjustment, the Administrator may approve 

the State’s proposed adjustments. If the adjustments are approved, the applicability of the 

requirement of paragraph (f)(3)(ii)(A) or (B) for a demonstration that there are no additional 

emission reduction measures for anthropogenic sources or groups of sources in the State that 

may reasonably be anticipated to contribute to visibility impairment in the Class I area that 

would be reasonable to include in the long-term strategy will be determined on the comparison 

of the reasonable progress goal and the uniform rate of progress after application of the approved 

adjustments. A state may propose and the Administrator may approve a method for coordinating 

adjustments under this paragraph with adjustments under paragraph (f)(3)(vi). 

(vi) A State with a Class I area, or a State that has emissions that are reasonably anticipated to 

contribute to visibility impairment in a Class I area in another State, may include in its plan an 

assessment of impacts on current and future visibility conditions at the Class I area from 

emissions from prescribed fires that were conducted under multi-year land or resource 

management plans for a wildland areas that have a stated objective to establish, restore, and/or 

maintain sustainable and resilient wildland ecosystems and/or to preserve endangered or 

threatened species through a program of prescribed fire and that provide for the use of 
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23 

appropriate basic smoke management practices, including information on the magnitude and 

temporal pattern of impacts from such emissions, and may propose adjustments to the value of 

the reasonable progress goal and/or the uniform rate of progress for application as part of the 

comparison between the reasonable progress goal and the uniform rate of progress required by 

paragraph (f)(3)(ii). The intended purpose of the adjustments is to remove the effect of such 

prescribed fire emissions from the determination of whether the plan provides progress equal to 

the uniform rate of progress. If the State has estimated such prescribed fire impacts and 

calculated the adjustments with methods and data that the Administrator determines are 

sufficiently reliable for the intended purpose of the adjustment, the Administrator may approve 

the State’s proposed adjustments. If the adjustments are approved, the applicability of the 

requirement of paragraph (f)(3)(ii)(A) or (B) for a demonstration that there are no additional 

emission reduction measures for anthropogenic sources or groups of sources in the State that 

may reasonably be anticipated to contribute to visibility impairment in the Class I area that 

would be reasonable to include in the long-term strategy will be determined on the comparison 

of the reasonable progress goal and the uniform rate of progress after application of the approved 

adjustments. A state may propose and the Administrator may approve a method for coordinating 

adjustments under this paragraph with adjustments under paragraph (f)(3)(v).

(4) If the Administrator, Regional Administrator, or the affected Federal Land Manager has 

advised a State of a need for additional monitoring to assess reasonably attributable visibility 

impairment at a mandatory Class I Federal area in addition to the monitoring currently being 

conducted, the State must include in the plan revision an appropriate strategy for evaluating 

reasonably attributable visibility impairment in the mandatory Class I Federal area by visual 

observation or other appropriate monitoring techniques. 

(5) So that the plan revision will serve also as a progress report, the State must address in the 

plan revision the requirements of paragraphs (g)(1), (g)(2), (g)(4), and (g)(5) of this section. 

However, the period to be addressed for these elements shall be the period since the past 

progress report. 

(6) Monitoring strategy and other implementation plan requirements. The State must submit 

with the implementation plan 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. Compliance with this requirement may be met through participation in the 

Interagency Monitoring of Protected Visual Environments network. The implementation plan 

must also provide for the following: 

(i) 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. 

(ii) 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. 
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(iii) For a State with no mandatory Class I Federal areas, 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 in other States. 

(iv) The implementation plan must provide for the reporting of all visibility monitoring data to 

the Administrator at least annually for each mandatory Class I Federal area in the State. To the 

extent possible, the State should report visibility monitoring data electronically. 

(v) 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. 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. The State must also include a commitment 

to update the inventory periodically. 

(vi) Other elements, including reporting, recordkeeping, and other measures, necessary to assess 

and report on visibility. 

(g) Requirements for periodic reports describing progress towards the reasonable progress 

goals. Each State identified in §51.300(b) must periodically submit a report to the Administrator 

evaluating progress towards the reasonable progress goal for 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. The first progress report is due 5 years 

from submittal of the initial implementation plan addressing paragraphs (d) and (e) of this 

section. The first progress reports must be in the form of implementation plan revisions that 

comply with the procedural requirements of §51.102 and §51.103. Subsequent progress reports 

are due by January 31, 2025, July 31, 2033, and every 10 years thereafter. Subsequent progress 

reports must be made available for public inspection and comment for at least 60 days prior to 

submission to EPA and all comments received from the public must be submitted to EPA along 

with the subsequent progress report, along with an explanation of any changes to the progress 

report made in response to these comments. Periodic progress reports must contain at a minimum 

the following elements: 

(1) A description of the status of implementation of all measures included in the implementation 

plan for achieving reasonable progress goals for mandatory Class I Federal areas both within and 

outside the State. 

(2) A summary of the emissions reductions achieved throughout the State through 

implementation of the measures described in paragraph (g)(1) of this section. 

(3) For each mandatory Class I Federal area within the State, the State must assess the following 

visibility conditions and changes, with values for most impaired, least impaired and/or clearest 

days as applicable expressed in terms of 5-year averages of these annual values. The period for 

calculating current visibility conditions is the most recent 5-year period preceding the required 

date of the progress report for which data are available as of a date 6 months preceding the 

required date of the progress report. 

(i)(A) Progress reports due before January 31, 2025. The current visibility conditions for the 

most impaired and least impaired days. 
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25 

(B) Progress reports due on and after January 31, 2025. The current visibility conditions for the 

most impaired and clearest days; 

(ii) (A) Progress reports due before January 31, 2025. The difference between current visibility 

conditions for the most impaired and least impaired days and baseline visibility conditions. 

(B) Progress reports due on and after January 31, 2025. The difference between current visibility 

conditions for the most impaired and clearest days and baseline visibility conditions. 

(iii) (A) Progress reports due before January 31, 2025. The change in visibility impairment for 

the most impaired and least impaired days over the period since the period addressed in the most 

recent plan required under paragraph (f) of this section. 

(B) Progress reports due on and after January 31, 2025. The change in visibility impairment for 

the most impaired and clearest days over the period since the period addressed in the most recent 

plan required under paragraph (f) of this section. 

(4) An analysis tracking the change over the period since the period addressed in the most recent 

plan required under paragraph (f) of this section in emissions of pollutants contributing to 

visibility impairment from all sources and activities within the State. Emissions changes should 

be identified by type of source or activity. With respect to all sources and activities, the analysis 

must extend at least through the most recent year for which the state has submitted emission 

inventory information to the Administrator in compliance with the triennial reporting 

requirements of subpart A of this part. With respect to sources that report directly to a centralized 

emissions data system operated by the Administrator, the analysis must extend through the most 

recent year for which the Administrator has provided a State-level summary of such reported 

data or an internet-based tool by which the State may obtain such a summary. The State is not 

required to backcast previously reported emissions to be consistent with more recent emissions 

estimation procedures, and may draw attention to actual or possible inconsistencies created by 

changes in estimation procedures. 

(5) An assessment of any significant changes in anthropogenic emissions within or outside the 

State that have occurred since the period addressed in the most recent plan required under 

paragraph (f) of this section including whether or not these changes in anthropogenic emissions 

were anticipated in that most recent plan and whether they have limited or impeded progress in 

reducing pollutant emissions and improving visibility. 

(6) An assessment of whether the current implementation plan elements and strategies are 

sufficient to enable the State, or other States with mandatory Class I Federal areas affected by 

emissions from the State, to meet all established reasonable progress goals for the period covered 

by the most recent plan required under paragraph (f) of this section. 

(h) Determination of the adequacy of existing implementation plan. At the same time the State is 

required to submit any progress report to EPA in accordance with paragraph (g) of this section, 

the State must also take one of the following actions based upon the information presented in the 

progress report: 

(1) If the State determines that the existing implementation plan requires no further substantive 

revision at this time in order to achieve established goals for visibility improvement and 
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emissions reductions, the State must provide to the Administrator a negative declaration that 

revision of the existing implementation plan is not needed at this time. 

(2) If the State determines that the implementation plan is or may be inadequate to ensure 

reasonable progress due to emissions from sources in another State(s) which participated in a 

regional planning process, the State must provide notification to the Administrator and to the 

other State(s) which participated in the regional planning process with the States. The State must 

also collaborate with the other State(s) through the regional planning process for the purpose of 

developing additional strategies to address the plan's deficiencies. 

(3) Where the State determines that the implementation plan is or may be inadequate to ensure 

reasonable progress due to emissions from sources in another country, the State shall provide 

notification, along with available information, to the Administrator. 

(4) Where the State determines that the implementation plan is or may be inadequate to ensure 

reasonable progress due to emissions from sources within the State, the State shall revise its 

implementation plan to address the plan's deficiencies within one year. 

(i) What are the requirements for State and Federal Land Manager coordination? (1) By 

November 29, 1999, the State must identify in writing to the Federal Land Managers the title of 

the official to which the Federal Land Manager of any mandatory Class I Federal area can submit 

any recommendations on the implementation of this subpart including, but not limited to: 

(i) Identification of impairment of visibility in any mandatory Class I Federal area(s); and 

(ii) Identification of elements for inclusion in the visibility monitoring strategy required by 

§51.305 and this section. 

(2) The State must provide the Federal Land Manager with an opportunity for consultation, in 

person at a point early enough in the State’s technical and policy analyses of its long-term 

strategy emission reduction obligation and prior to development of reasonable progress goals 

planning the development of its long-term strategy so that information and recommendations 

provided by the Federal Land Manager can meaningfully inform the State’s development of the 

long-term strategy. The opportunity for consultation will be deemed to have been early enough if 

the consultation has taken place, and at least 60 120 days prior to holding any public hearing or 

other public comment opportunity on an implementation plan (or plan revision) or progress 

report for regional haze required by this subpart. The opportunity for consultation must be 

provided no less than 60 days prior to said public hearing or public comment opportunity. This 

consultation must include the opportunity for the affected Federal Land Managers to discuss 

their: 

(i) Assessment of impairment of visibility in any mandatory Class I Federal area; and 

(ii) Recommendations on the development of the reasonable progress goal and on the 

development and implementation of strategies to address visibility impairment. 

(3) In developing any implementation plan (or plan revision) or progress report, the State must 

include a description of how it addressed any comments provided by the Federal Land Managers. 

(4) The plan (or plan revision) must provide procedures for continuing consultation between the 

State and Federal Land Manager on the implementation of the visibility protection program 
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required by this subpart, including development and review of implementation plan revisions and 

progress reports, and on the implementation of other programs having the potential to contribute 

to impairment of visibility in mandatory Class I Federal areas. 

§51.309 Requirements related to the Grand Canyon Visibility Transport Commission. 

(a) What is the purpose of this section? This section establishes the requirements for the first 

regional haze implementation plan to address regional haze visibility impairment in the 16 Class 

I areas covered by the Grand Canyon Visibility Transport Commission Report. For the period 

through 2018, certain States (defined in paragraph (b) of this section as Transport Region States) 

may choose to implement the Commission's recommendations within the framework of the 

national regional haze program and applicable requirements of the Act by complying with the 

provisions of this section. If a Transport Region State submits an implementation plan which is 

approved by EPA as meeting the requirements of this section, it will be deemed to comply with 

the requirements for reasonable progress with respect to the 16 Class I areas for the period from 

approval of the plan through 2018. Any Transport Region State electing not to submit an 

implementation plan under this section is subject to the requirements of §51.308 in the same 

manner and to the same extent as any State not included within the Transport Region. Except as 

provided in paragraph (g) of this section, each Transport Region State is also subject to the 

requirements of §51.308 with respect to any other Federal mandatory Class I areas within the 

State or affected by emissions from the State. 

(b) Definitions. For the purposes of this section: 

(1) 16 Class I areas means the following mandatory Class I Federal areas on the Colorado 

Plateau: Grand Canyon National Park, Sycamore Canyon Wilderness, Petrified Forest National 

Park, Mount Baldy Wilderness, San Pedro Parks Wilderness, Mesa Verde National Park, 

Weminuche Wilderness, Black Canyon of the Gunnison Wilderness, West Elk Wilderness, 

Maroon Bells Wilderness, Flat Tops Wilderness, Arches National Park, Canyonlands National 

Park, Capital Reef National Park, Bryce Canyon National Park, and Zion National Park. 

(2) Transport Region State means one of the States that is included within the Transport Region 

addressed by the Grand Canyon Visibility Transport Commission (Arizona, California, 

Colorado, Idaho, Nevada, New Mexico, Oregon, Utah, and Wyoming). 

(3) Commission Report means the report of the Grand Canyon Visibility Transport Commission 

entitled “Recommendations for Improving Western Vistas,” dated June 10, 1996. 

(4) Fire means wildfire, wildland fire (including prescribed natural fire), prescribed fire, and 

agricultural burning conducted and occurring on Federal, State, and private wildlands and 

farmlands. 

(5) Milestone means the maximum level of annual regional SO2 emissions, in tons per year, for a 

given year, assessed annually, through the year 2018, consistent with paragraph (d)(4) of this 

section. 

(6) Continuous decline in total mobile source emissions means that the projected level of 

emissions from mobile sources of each listed pollutant in 2008, 2013, and 2018, are less than the 
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28 

projected level of emissions from mobile sources of each listed pollutant for the previous period 

(i.e., 2008 less than 2003; 2013 less than 2008; and 2018 less than 2013). 

(7) Base year means the year for which data for a source included within the program were used 

by the WRAP to calculate emissions as a starting point for development of the milestone 

required by paragraph (d)(4)(i) of this section. 

(8) Base year means the year, generally a year between 1996 and 1998, for which data for a 

source included within the program were used by the WRAP to calculate base year emissions as 

a starting point for development of the Annex required by paragraph (f) of this section. 

(9)-(12) [Reserved] 

(13) Eligible renewable energy resource, for purposes of 40 CFR 51.309, means electricity 

generated by non-nuclear and non-fossil low or no air emission technologies. 

(c) Implementation Plan Schedule. Each Transport Region State electing to submit an 

implementation plan under this section must submit such a plan no later than December 17, 

2007. Indian Tribes may submit implementation plans after this deadline. 

(d) Requirements of the first implementation plan for States electing to adopt all of the 

recommendations of the Commission Report. Except as provided for in paragraph (e) of this 

section, each Transport Region State must submit an implementation plan that meets the 

following requirements: 

(1) Time period covered. The implementation plan must be effective through December 31, 2018 

and continue in effect until an implementation plan revision is approved by EPA in accordance 

with §51.308(f). 

(2) Projection of visibility improvement. For each of the 16 mandatory Class I areas located

within the Transport Region State, the plan must include a projection of the improvement in 

visibility conditions (expressed in deciviews, and in any additional ambient visibility metrics 

deemed appropriate by the State) expected through the year 2018 for the most impaired and least 

impaired days, based on the implementation of all measures as required in the Commission 

report and the provisions in this section. The projection must be made in consultation with other 

Transport Region States with sources which may be reasonably anticipated to contribute to 

visibility impairment in the relevant Class I area. The projection may be based on a satisfactory 

regional analysis. 

(3) Treatment of clean-air corridors. The plan must describe and provide for implementation of 

comprehensive emission tracking strategies for clean-air corridors to ensure that the visibility 

does not degrade on the least-impaired days at any of the 16 Class I areas. The strategy must 

include: 

(i) An identification of clean-air corridors. The EPA will evaluate the State's identification of 

such corridors based upon the reports of the Commission's Meteorology Subcommittee and any 

future updates by a successor organization; 

(ii) Within areas that are clean-air corridors, an identification of patterns of growth or specific 

sites of growth that could cause, or are causing, significant emissions increases that could have, 

or are having, visibility impairment at one or more of the 16 Class I areas. 
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(iii) In areas outside of clean-air corridors, an identification of significant emissions growth that 

could begin, or is beginning, to impair the quality of air in the corridor and thereby lead to 

visibility degradation for the least-impaired days in one or more of the 16 Class I areas. 

(iv) If impairment of air quality in clean air corridors is identified pursuant to paragraphs 

(d)(3)(ii) and (iii) of this section, an analysis of the effects of increased emissions, including 

provisions for the identification of the need for additional emission reductions measures, and 

implementation of the additional measures where necessary. 

(v) A determination of whether other clean air corridors exist for any of the 16 Class I areas. For 

any such clean air corridors, an identification of the necessary measures to protect against future 

degradation of air quality in any of the 16 Class I areas. 

(4) Implementation of stationary source reductions. The first implementation plan submission 

must include: 

(i) Provisions for stationary source emissions of SO2. The plan submission must include a SO2 

program that contains quantitative emissions milestones for stationary source SO2 emissions for 

each year through 2018. After the first two years of the program, compliance with the annual 

milestones may be measured by comparing a three-year rolling average of actual emissions with 

a rolling average of the emissions milestones for the same three years. During the first two years 

of the program, compliance with the milestones may be measured by a methodology of the 

States' choosing, so long as all States in the program use the same methodology. Compliance 

with the 2018 milestone shall be measured by comparing actual emissions from the year 2018 

with the 2018 milestone. The milestones must provide for steady and continuing emissions 

reductions through 2018 consistent with the Commission's definition of reasonable progress, its 

goal of 50 to 70 percent reduction in SO2 emissions from 1990 actual emission levels by 2040, 

applicable requirements under the CAA, and the timing of implementation plan assessments of 

progress and identification of any deficiencies which will be due in the years 2013 and 2018. The 

milestones must be shown to provide for greater reasonable progress than would be achieved by 

application of BART pursuant to §51.308(e)(2). 

(ii) Documentation of emissions calculation methods for SO2. The plan submission must include 

documentation of the specific methodology used to calculate SO2 emissions during the base year 

for each emitting unit included in the program. The implementation plan must also provide for 

documentation of any change to the specific methodology used to calculate emissions at any 

emitting unit for any year after the base year. 

(iii) Monitoring, recordkeeping, and reporting of SO2 emissions. The plan submission must 

include provisions requiring the monitoring, recordkeeping, and annual reporting of actual 

stationary source SO2 emissions within the State. The monitoring, recordkeeping, and reporting 

data must be sufficient to determine annually whether the milestone for each year through 2018 

is achieved. The plan submission must provide for reporting of these data by the State to the 

Administrator and to the regional planning organization. The plan must provide for retention of 

records for at least 10 years from the establishment of the record. 

(iv) Criteria and Procedures for a Market Trading Program. The plan must include the criteria 

and procedures for conducting an annual evaluation of whether the milestone is achieved and, in 
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accordance with paragraph (d)(4)(v) of this section, for activating a market trading program in 

the event the milestone is not achieved. A draft of the annual report evaluating whether the 

milestone for each year is achieved shall be completed no later than 12 months from the end of 

each milestone year. The plan must also provide for assessments of the program in the years 

2013 and 2018. 

(v) Market Trading Program. The implementation plan must include requirements for a market 

trading program to be implemented in the event that a milestone is not achieved. The plan shall 

require that the market trading program be activated beginning no later than 15 months after the 

end of the first year in which the milestone is not achieved. The plan shall also require that 

sources comply, as soon as practicable, with the requirement to hold allowances covering their 

emissions. Such market trading program must be sufficient to achieve the milestones in 

paragraph (d)(4)(i) of this section, and must be consistent with the elements for such programs 

outlined in §51.308(e)(2)(vi). Such a program may include a geographic enhancement to the 

program to address the requirement under §51.302(b) related to reasonably attributable 

impairment from the pollutants covered under the program. 

(vi) Provision for the 2018 milestone. 

(A) Unless and until a revised implementation plan is submitted in accordance with §51.308(f) 

and approved by EPA, the implementation plan shall prohibit emissions from covered stationary 

sources in any year beginning in 2018 that exceed the year 2018 milestone. In no event shall a 

market-based program approved under §51.308(f) allow an emissions cap for SO2 that is less 

stringent than the 2018 milestone, unless the milestones are replaced by a different program 

approved by EPA as meeting the BART and reasonable progress requirements established in 

§51.308. 

(B) The implementation plan must provide a framework, including financial penalties for excess 

emissions based on the 2018 milestone, sufficient to ensure that the 2018 milestone will be met 

even if the implementation of the market trading program in paragraph (d)(4)(v) of this section 

has not yet been triggered, or the source allowance compliance provision of the trading program 

is not yet in effect. 

(vii) Provisions for stationary source emissions of NOX and PM. The implementation plan must 

contain any necessary long term strategies and BART requirements for stationary source PM and 

NOX emissions. Any such BART provisions may be submitted pursuant to either §51.308(e)(1) 

or '51.308(e)(2). 

(5) Mobile sources. The plan submission must provide for: 

(i) Statewide inventories of onroad and nonroad mobile source emissions of VOC, NOX, SO2, 

PM2.5, elemental carbon, and organic carbon for the years 2003, 2008, 2013, and 2018. 

(A) The inventories must demonstrate a continuous decline in total mobile source emissions 

(onroad plus nonroad; tailpipe and evaporative) of VOC, NOX, PM2.5, elemental carbon, and 

organic carbon, evaluated separately. If the inventories show a continuous decline in total mobile 

source emissions of each of these pollutants over the period 2003-2018, no further action is 

required as part of this plan to address mobile source emissions of these pollutants. If the 

inventories do not show a continuous decline in mobile source emissions of one or more of these 
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pollutants over the period 2003-2018, the plan submission must provide for an implementation 

plan revision by no later than December 31, 2008 containing any necessary long-term strategies 

to achieve a continuous decline in total mobile source emissions of the pollutant(s), to the extent 

practicable, considering economic and technological reasonableness and federal preemption of 

vehicle standards and fuel standards under title II of the CAA. 

(B) The plan submission must also provide for an implementation plan revision by no later than 

December 31, 2008 containing any long-term strategies necessary to reduce emissions of SO2

from nonroad mobile sources, consistent with the goal of reasonable progress. In assessing the 

need for such long-term strategies, the State may consider emissions reductions achieved or 

anticipated from any new Federal standards for sulfur in nonroad diesel fuel. 

(ii) Interim reports to EPA and the public in years 2003, 2008, 2013, and 2018 on the 

implementation status of the regional and local strategies recommended by the Commission 

Report to address mobile source emissions. 

(6) Programs related to fire. The plan must provide for: 

(i) Documentation that all Federal, State, and private prescribed fire programs within the State 

evaluate and address the degree visibility impairment from smoke in their planning and 

application. In addition the plan must include smoke management programs that include all 

necessary components including, but not limited to, actions to minimize emissions, evaluation of 

smoke dispersion, alternatives to fire, public notification, air quality monitoring, surveillance and 

enforcement, and program evaluation. 

(ii) A statewide inventory and emissions tracking system (spatial and temporal) of VOC, NOX, 

elemental and organic carbon, and fine particle emissions from fire. In reporting and tracking 

emissions from fire from within the State, States may use information from regional datagathering and tracking initiatives. 

(iii) Identification and removal wherever feasible of any administrative barriers to the use of 

alternatives to burning in Federal, State, and private prescribed fire programs within the State. 

(iv) Enhanced smoke management programs for fire that consider visibility effects, not only 

health and nuisance objectives, and that are based on the criteria of efficiency, economics, law, 

emission reduction opportunities, land management objectives, and reduction of visibility 

impact. 

(v) Establishment of annual emission goals for fire, excluding wildfire, that will minimize 

emission increases from fire to the maximum extent feasible and that are established in 

cooperation with States, tribes, Federal land management agencies, and private entities. 

(7) Area sources of dust emissions from paved and unpaved roads. The plan must include an 

assessment of the impact of dust emissions from paved and unpaved roads on visibility 

conditions in the 16 Class I Areas. If such dust emissions are determined to be a significant 

contributor to visibility impairment in the 16 Class I areas, the State must implement emissions 

management strategies to address the impact as necessary and appropriate. 

(8) Pollution prevention. The plan must provide for: 
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(i) An initial summary of all pollution prevention programs currently in place, an inventory of all 

renewable energy generation capacity and production in use, or planned as of the year 2002 

(expressed in megawatts and megawatt-hours), the total energy generation capacity and 

production for the State, the percent of the total that is renewable energy, and the State's 

anticipated contribution toward the renewable energy goals for 2005 and 2015, as provided in 

paragraph (d)(8)(vi) of this section. 

(ii) Programs to provide incentives that reward efforts that go beyond compliance and/or achieve 

early compliance with air-pollution related requirements. 

(iii) Programs to preserve and expand energy conservation efforts. 

(iv) The identification of specific areas where renewable energy has the potential to supply 

power where it is now lacking and where renewable energy is most cost-effective. 

(v) Projections of the short- and long-term emissions reductions, visibility improvements, cost 

savings, and secondary benefits associated with the renewable energy goals, energy efficiency 

and pollution prevention activities. 

(vi) A description of the programs relied on to achieve the State's contribution toward the 

Commission's goal that renewable energy will comprise 10 percent of the regional power needs 

by 2005 and 20 percent by 2015, and a demonstration of the progress toward achievement of the 

renewable energy goals in the years 2003, 2008, 2013, and 2018. This description must include 

documentation of the potential for renewable energy resources, the percentage of renewable 

energy associated with new power generation projects implemented or planned, and the 

renewable energy generation capacity and production in use and planned in the State. To the 

extent that it is not feasible for a State to meet its contribution to the regional renewable energy 

goals, the State must identify in the progress reports the measures implemented to achieve its 

contribution and explain why meeting the State's contribution was not feasible. 

(9) Implementation of additional recommendations. The plan must provide for implementation of 

all other recommendations in the Commission report that can be practicably included as 

enforceable emission limits, schedules of compliance, or other enforceable measures (including 

economic incentives) to make reasonable progress toward remedying existing and preventing 

future regional haze in the 16 Class I areas. The State must provide a report to EPA and the 

public in 2003, 2008, 2013, and 2018 on the progress toward developing and implementing 

policy or strategy options recommended in the Commission Report. 

(10) Periodic implementation plan revisions and progress reports. Each Transport Region State 

must submit to the Administrator periodic reports in the years 2013 and as specified for 

subsequent progress reports in §51.308(g). The progress report due in 2013 must be in the form 

of an implementation plan revision that complies with the procedural requirements of §§51.102 

and 51.103. 

(i) The report due in 2013 will assess the area for reasonable progress as provided in this section 

for mandatory Class I Federal area(s) located within the State and for mandatory Class I Federal 

area(s) located outside the State that may be affected by emissions from within the State. This 

demonstration may be based on assessments conducted by the States and/or a regional planning 

body. The progress report due in 2013 must contain at a minimum the following elements: 
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(A) A description of the status of implementation of all measures included in the implementation 

plan for achieving reasonable progress goals for mandatory Class I Federal areas both within and 

outside the State. 

(B) A summary of the emissions reductions achieved throughout the State through 

implementation of the measures described in paragraph (d)(10)(i)(A) of this section. 

(C) For each mandatory Class I Federal area within the State, an assessment of the following: the 

current visibility conditions for the most impaired and least impaired days; the difference 

between current visibility conditions for the most impaired and least impaired days and baseline 

visibility conditions; the change in visibility impairment for the most impaired and least impaired 

days over the past 5 years. 

(D) An analysis tracking the change over the past 5 years in emissions of pollutants contributing 

to visibility impairment from all sources and activities within the State. Emissions changes 

should be identified by type of source or activity. The analysis must be based on the most recent 

updated emissions inventory, with estimates projected forward as necessary and appropriate, to 

account for emissions changes during the applicable 5-year period. 

(E) An assessment of any significant changes in anthropogenic emissions within or outside the 

State that have occurred over the past 5 years that have limited or impeded progress in reducing 

pollutant emissions and improving visibility. 

(F) An assessment of whether the current implementation plan elements and strategies are 

sufficient to enable the State, or other States with mandatory Federal Class I areas affected by 

emissions from the State, to meet all established reasonable progress goals. 

(G) A review of the State's visibility monitoring strategy and any modifications to the strategy as 

necessary. 

(ii) At the same time the State is required to submit the 5-year progress report due in 2013 to 

EPA in accordance with paragraph (d)(10)(i) of this section, the State must also take one of the 

following actions based upon the information presented in the progress report: 

(A) If the State determines that the existing implementation plan requires no further substantive 

revision at this time in order to achieve established goals for visibility improvement and 

emissions reductions, the State must provide to the Administrator a negative declaration that 

further revision of the existing implementation plan is not needed at this time. 

(B) If the State determines that the implementation plan is or may be inadequate to ensure 

reasonable progress due to emissions from sources in another State(s) which participated in a 

regional planning process, the State must provide notification to the Administrator and to the 

other State(s) which participated in the regional planning process with the States. The State must 

also collaborate with the other State(s) through the regional planning process for the purpose of 

developing additional strategies to address the plan's deficiencies. 

(C) Where the State determines that the implementation plan is or may be inadequate to ensure 

reasonable progress due to emissions from sources in another country, the State shall provide 

notification, along with available information, to the Administrator. 
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34 

(D) Where the State determines that the implementation plan is or may be inadequate to ensure 

reasonable progress due to emissions from within the State, the State shall develop additional 

strategies to address the plan deficiencies and revise the implementation plan no later than one 

year from the date that the progress report was due. 

(iii) The requirements of §51.308(g) regarding requirements for periodic reports describing 

progress towards the reasonable progress goals apply to States submitting plans under this 

section, with respect to subsequent progress reports due after 2013. 

(iv) The requirements of §51.308(h) regarding determinations of the adequacy of existing 

implementation plans apply to States submitting plans under this section, with respect to 

subsequent progress reports due after 2013. 

 (11) State planning and interstate coordination. In complying with the requirements of this 

section, States may include emission reductions strategies that are based on coordinated 

implementation with other States. Examples of these strategies include economic incentive 

programs and transboundary emissions trading programs. The implementation plan must include 

documentation of the technical and policy basis for the individual State apportionment (or the 

procedures for apportionment throughout the trans-boundary region), the contribution addressed 

by the State's plan, how it coordinates with other State plans, and compliance with any other 

appropriate implementation plan approvability criteria. States may rely on the relevant technical, 

policy and other analyses developed by a regional entity (such as the Western Regional Air 

Partnership) in providing such documentation. Conversely, States may elect to develop their own 

programs without relying on work products from a regional entity. 

(12) Tribal implementation. Consistent with 40 CFR Part 49, tribes within the Transport Region 

may implement the required visibility programs for the 16 Class I areas, in the same manner as 

States, regardless of whether such tribes have participated as members of a visibility transport 

commission. 

(e) States electing not to implement the commission recommendations. Any Transport Region 

State may elect not to implement the Commission recommendations set forth in paragraph (d) of 

this section. Such States are required to comply with the timelines and requirements of §51.308. 

Any Transport Region State electing not to implement the Commission recommendations must 

advise the other States in the Transport Region of the nature of the program and the effect of the 

program on visibility-impairing emissions, so that other States can take this information into 

account in developing programs under this section. 

(f) [Reserved] 

(g) Additional Class I areas. Each Transport Region State implementing the provisions of this 

section as the basis for demonstrating reasonable progress for mandatory Class I Federal areas 

other than the 16 Class I areas must include the following provisions in its implementation plan. 

If a Transport Region State submits an implementation plan which is approved by EPA as 

meeting the requirements of this section, it will be deemed to comply with the requirements for 

reasonable progress for the period from approval of the plan to 2018. 

(1) A demonstration of expected visibility conditions for the most impaired and least impaired 

days at the additional mandatory Class I Federal area(s) based on emissions projections from the 
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35 

long-term strategies in the implementation plan. This demonstration may be based on 

assessments conducted by the States and/or a regional planning body. 

(2) Provisions establishing reasonable progress goals and implementing any additional measures 

necessary to demonstrate reasonable progress for the additional mandatory Federal Class I areas. 

These provisions must comply with the provisions of §51.308(d)(1) through (4). 

(i) In developing long-term strategies pursuant to §51.308(d)(3), the State may build upon the 

strategies implemented under paragraph (d) of this section, and take full credit for the visibility 

improvement achieved through these strategies. 

(ii) The requirement under §51.308(e) related to Best Available Retrofit Technology for regional 

haze is deemed to be satisfied for pollutants addressed by the milestones and backstop trading 

program if, in establishing the emission reductions milestones under paragraph (d)(4) of this 

section, it is shown that greater reasonable progress will be achieved for these additional Class I 

areas than would be achieved through the application of source-specific BART emission 

limitations under §51.308(e)(1). 

(iii) The Transport Region State may consider whether any strategies necessary to achieve the 

reasonable progress goals required by paragraph (g)(2) of this section are incompatible with the 

strategies implemented under paragraph (d) of this section to the extent the State adequately 

demonstrates that the incompatibility is related to the costs of the compliance, the time necessary 

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

remaining useful life of any existing source subject to such requirements.