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Revised Express Terms 

6 NYCRR Part 249, Best Available Retrofit Technology (BART) 

249.1 Purpose and Applicability 

249.2 Definitions 

249.3 Requirements for Sources Subject to Case-by-Case BART Determinations 

249.4 Emissions Tests and Monitoring 

Section 249.1 Purpose and Applicability 

 (a) This Part restricts the emissions of visibility-impairing pollutants by requiring the installation of Best 

Available Retrofit Technology (BART) on a BART-eligible stationary source to reduce regional haze and 

restore natural visibility conditions to Federal Class I Areas. 

(b) Except as provided under Subdivision (c) of this Section, this Part applies to any stationary source 

that has been determined to be BART-eligible and whose emissions require control pursuant to section 169A of 

the Act. BART-eligible refers to any stationary source that: 

(1) is in one of 26 specific source categories identified in Section 231-2.2(c) (1) through (26) of 

this Title; 

 (2) was not in operation prior to August 7, 1962 and was in existence on August 7, 1977, or 

underwent reconstruction between August 7, 1962 and August 7, 1977; and, 
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(3) has a potential to emit (PTE) 250 tons per year (tpy) or more of any visibility-impairing 

pollutant. 

(c) Exempted from the provisions of this Part is any BART-eligible source that: 

(1) is subject to a permit condition that restricts the source’s PTE to less than 250 tpy for each 

visibility-impairing pollutant; 

(2) is subject to a permit condition that requires the source to permanently shut down by January 

1, 2014; or, 

 (3) has shown through modeling or other means acceptable to the department that it does not or 

will not emit any combination of visibility-impairing pollutants that results in a visibility impairment 

equal to or greater than 0.1 deciviews in any Federal Class I Area. 

Section 249.2 Definitions 

For the purpose of this regulation, the following definitions apply: 

 (a) ‘Best Available Retrofit Technology’ or ‘BART.’ An emission limitation based on the degree of 

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

visibility-impairing pollutant which is emitted by an existing stationary facility. BART for any individual 

source is determined by undertaking the case-by-case analysis required under Section 249.3 of this Part. 

 
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 (b) ‘Deciview.’ A measurement of visibility impairment. A deciview is a haze index derived from 

calculated light extinction, such that uniform changes in haziness correspond to uniform incremental changes in 

perception across the entire range of conditions, from pristine to highly impaired. The deciview haze index is 

calculated based on the following equation (for the purposes of calculating deciview, the atmospheric light 

extinction coefficient must be calculated from aerosol measurements): 

HI = 10 ln (b/10) 

Where b = the atmospheric light extinction coefficient, expressed in inverse megameters (Mm-1). 

(c) ‘Federal Class I Area.’ A national park which exceeds 6,000 acres, national wilderness area which 

exceeds 5,000 acres, national memorial park which exceeds 5,000 acres, or any international park, which was in 

existence as of August 7, 1977. 

(d) ‘In existence.’ As used in Section 249.1(b)(2) of this Part, 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 onsite construction of the facility or (2) entered into binding agreements or contractual obligations, which cannot 

be canceled 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. 

(e) ‘Light extinction.’ The process of light being absorbed or scattered as it passes through a medium, 

such as the atmosphere. 
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 (f) ‘Natural Visibility Conditions.’ Includes naturally occurring phenomena that reduce visibility as 

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

 

 (g) ‘Reconstruction.’ 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 40 CFR 60.15 (f) (1) through (3).

(h) ‘Regional haze.’ Visibility impairment that is caused by the emission of visibility-impairing air 

pollutants from numerous sources located over a wide geographic area. 

(i) ‘Visibility-impairing pollutant.’ Sulfur dioxide (SO2), nitrogen oxides (NOx), and particulate matter 

less than or equal to 10 microns in diameter (PM10). 

(j) ‘Visibility impairment.’ Any humanly perceptible change in visibility (light extinction, visual range, 

contrast, coloration) from that which would have existed under natural conditions. 

Section 249.3 Requirements for Sources Subject to Case-by-Case BART Determinations 

 (a) The owner or operator of a source that is determined to be BART-eligible and whose emissions of 

visibility-impairing pollutants result in a visibility impairment equal to or greater than 0.1 deciviews in any 

Federal Class I Area must conduct an analysis to determine the appropriate emission limitation necessary to 

meet BART requirements. The analysis must consider, with respect to each visibility-impairing pollutant 

emitted by the source, the following factors: 

 

(1) the costs of compliance; 
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 (2) the energy and non-air quality environmental impacts of compliance; 

 (3) any existing pollution control technology in use at the source; 

 (4) the remaining useful life of the source; and, 

 (5) the degree of improvement in visibility which may reasonably be anticipated to result from 

the use of such technology. 

 (b) The analysis must evaluate retrofit control options for each visibility-impairing pollutant unless 

facility-wide emissions for the relevant visibility-impairing pollutant are at or below the de minimis level. The 

facility-wide de minimis emissions levels are 40 tpy of SO2 or NOx, and 15 tpy of PM10. 

 (c) Any required BART analysis must be submitted to the department by October 1, 2010. 

 (d) Control equipment or other emission reduction methods approved by the department as BART must 

be installed and operating no later than January 1, 2014.

(e) Before commencing any required construction or process changes, the owner or operator must 

submit an application for a permit or permit modification as required under Part 201 of this Title.

 (f) Each BART determination established by the Department will be submitted to the United States 

Environmental Protection Agency for approval as a revision to the State Implementation Plan. 
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Section 249.4 Emissions Tests and Monitoring 

 (a) The owner or operator of the stationary source to which BART requirements apply must perform an 

emissions test according to a protocol approved by the department. This protocol must be submitted within six 

months of the commencement of operation of the BART controls. The protocol must include a schedule (using 

the date of department approval of the protocol as the starting event) for the performance of the required 

emissions test and submission of the emissions test report. The emissions test must demonstrate that the 

necessary emission reductions of visibility-impairing pollutants and other requirements under this Part are being 

met. Testing methods for particulate matter must quantify the emissions of PM10 and particulate matter less 

than or equal to 2.5 microns in diameter (PM2.5). Both filterable and condensable particulate matter must be 

included. 

 (b) The owner or operator of the stationary source subject to BART requirements must provide, along 

with the analysis required under Section 249.3 of this Part, a proposal for an appropriate emissions monitoring 

technology that will be implemented at the source.