1 For the reasons set forth in the preamble, part 51 of chapter I of title 40 of the Code of Federal Regulations is proposed to be amended as follows:

PART 51 REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS 1. The authority citation for part 51 continues to read as follows:

Authority: 23 U. S. C. 101; 42 U. S. C. 7410 7671q.

2. Section 51.302 is amended by revising paragraph ( c)( 4)( iii) to read as follows:

§ 51.302 Implementation control strategies for reasonably attributable visibility impairment.

* * * * *

( c) * * *

( 4) * * *

( iii) BART must be determined for fossil fuel fired generating plants having a total generating capacity in excess of 750 megawatts pursuant to " Guidelines for Determining Best Available Retrofit Technology for Coal fired Power Plants and Other Existing Stationary Facilities" ( 1980), which is incorporated by reference, exclusive of appendix E, which was published in the Federal Register on February 6, 1980 ( 45 FR 8210), except that options more stringent than NSPS must be 2 considered. Establishing a BART emission limitation equivalent to the NSPS level of control is not a sufficient basis to avoid the detailed analysis of control options required by the guidelines. This document is EPA publication No. 450/ 3 80 009b and is for sale from the U. S. Department of Commerce, National Technical Information Service, 5285 Port Royal Road, Springfield,

Virginia 22161.

* * * * *

3. Section 51.308 is amended by revising paragraphs ( b),

( c), and ( e)( 1)( ii) to read as follows:

§ 51.308 Regional haze program requirements.

* * * * *

( 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)( 3) 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) [ Reserved]

* * * * *

( e) * * *

( 1) * * *

( ii) A determination of BART for each BART eligible source in the State that emits any air pollutant which may reasonably be 3 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 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).

( iii) * * *

( A) * * *

( B) 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 4 pollutant( s), or for PM10 if a BART eligible source emits less than 15 tons per year of such pollutant.

* * * * * 5 5. Appendix Y to Part 51 is added to read as follows:

Appendix Y to Part 51  Guidelines for BART Determinations Under the Regional Haze Rule Table of Contents:

I. Introduction and Overview A. What is the purpose of the guidelines?

B. What does the CAA require generally for improving visibility?

C. What is the BART requirement in the CAA?

D. What types of visibility problems does EPA address in its regulations?

E. What are the BART requirements in EPA's regional haze regulations?

F. What is included in the guidelines?

G. Who is the target audience for the guidelines?

H. Do EPA regulations require the use of these guidelines?

II. How to Identify BART eligible Sources A. What are the steps in identifying BART eligible sources?

1. Step 1: Identify emission units in the BART categories 2. Step 2: Identify the start up dates of the emission units 3. Step 3: Compare the potential emissions to the 250 6 ton/ yr cutoff 4. Final step: Identify the emission units and pollutants that constitute the BART eligible source.

III. How to Identify Sources " Subject to BART"

IV. The BART Determination: Analysis of BART Options A. What factors must I address in the BART Analysis?

B. How does a BART review compare to a BACT review under the PSD program?

CB. What is the scope of the BART review?

DC. How does a BART review relate to maximum achievable control technology ( MACT) standards under CAA section 112?

ED. What are the five basic steps of a case by case BART analysis?

1. Step 1: How do I identify all available retrofit emission control techniques?

2. Step 2: How do I determine whether the options identified in Step 1 are technically feasible?

3. Step 3: How do I develop a ranking of the evaluate technically feasible alternatives?

4. Step 4: For a BART review, what impacts must I am I expected to calculate and report? What methods does EPA recommend for the impacts analyses?

a. Impact analysis part 1: how do I estimate the costs of control? 7 b. How do I take into account a project's " remaining useful life" in calculating control costs?

c. What do we mean by cost effectiveness?

d. How do I calculate average cost effectiveness?

e. How do I calculate baseline emissions?

f. How do I calculate incremental cost effectiveness?

g. What other information should I provide in the cost impacts analysis?

h. Impact analysis part 2: How should I analyze and report energy impacts?

i. Impact analysis part 3: How do I analyze " non air quality environmental impacts?"

j. What are examples of non air quality environmental impacts?

5. Step 5: How should I determine visibility impacts in the BART determination?

FE. How do I select the " best" alternative, using the results of Steps 1 through 5?

1. Summary of the impacts analysis 2. Selecting a " best" alternative 3. In selecting a " best" alternative, should I consider the affordability of controls?

4. SO2 limits for utility boilers 5. NOx limits for utility boilers 8 V. Enforceable Limits / Compliance Date I. INTRODUCTION AND OVERVIEW C. What is the purpose of the guidelines?

The Clean Air Act ( CAA), in sections 169A and 169B, contains requirements for the protection of visibility in 156 scenic areas across the United States. To meet the CAA's requirements, we published regulations to protect against a particular type of visibility impairment known as " regional haze." The regional haze rule is found in this part at 40 CFR 51.300 through 51.309.

These regulations require, in 40 CFR 51.308( e), that certain types of existing stationary sources of air pollutants install best available retrofit technology ( BART). The guidelines are designed to help States and others ( 1) identify those sources that must comply with the BART requirement, and ( 2) determine the level of control technology that represents BART for each source.

B. What does the CAA require generally for improving visibility?

Section 169A of the CAA, added to the CAA by the 1977 amendments, requires States to protect and improve visibility in certain scenic areas of national importance. The scenic areas protected by section 169A are " the mandatory Class I Federal Areas . . . where visibility is an important value." In these guidelines, we refer to these as " Class I areas." There are 156 Class I areas, including 47 national parks ( under the 9 jurisdiction of the Department of Interior  National Park Service), 108 wilderness areas ( under the jurisdiction of the Department of Interior  Fish and Wildlife Service or the Department of Agriculture   U. S. Forest Service), and one International Park ( under the jurisdiction of the Roosevelt

Campobello International Commission). The Federal Agency with jurisdiction over a particular Class I area is referred to in the CAA as the Federal Land Manager. A complete list of the Class I areas is contained in 40 CFR 81.401 through 81.437, and you can find a map of the Class I areas at the following internet site:

http:// www. epa. gov/ ttn/ oarpg/ t1/ fr_ notices/ classimp. gif The CAA establishes a national goal of eliminating man made visibility impairment from all Class I areas. As part of the plan for achieving this goal, the visibility protection provisions in the CAA mandate that EPA issue regulations requiring that States adopt measures in their State implementation plans ( SIPs), including long term strategies, to provide for reasonable progress towards this national goal. The CAA also requires States to coordinate with the Federal Land Managers as they develop their strategies for addressing visibility.

C. What is the BART requirement in the CAA?

1. Under section 169A( b)( 2)( A) of the CAA, States must require certain existing stationary sources to install BART. The BART 10 requirement applies to " major stationary sources" from 26 identified source categories which have the potential to emit 250 tons per year or more of any air pollutant. The CAA requires only sources which were put in place during a specific 15 year time interval to install BART. The BART requirement applies to sources that existed as of the date of the 1977 CAA amendments ( that is, August 7, 1977) but which had not been in operation for more than 15 years ( that is, not in operation as of August 7,

1962).

2. The CAA requires BART review when any source meeting the above description " emits any air pollutant which may reasonably be anticipated to cause or contribute to any impairment of visibility" in any Class I area. In identifying a level of control as BART, States are required by section 169A( g) of the CAA to consider:

( a) the costs of compliance,

( b) the energy and non air quality environmental impacts of compliance,

( c) any existing pollution control technology in use at the source,

( d) the remaining useful life of the source, and ( e) the degree of visibility improvement which may reasonably be anticipated from the use of BART.

3. The CAA further requires States to make BART emission 11 limitations part of their SIPs. As with any SIP revision, States must provide an opportunity for public comment on the BART determinations, and EPA's action on any SIP revision will be subject to judicial review.

D. What types of visibility problems does EPA address in its regulations?

1. We addressed the problem of visibility in two phases. In 1980, we published regulations addressing what we termed " reasonably attributable" visibility impairment. Reasonably attributable visibility impairment is the result of emissions from one or a few sources that are generally located in close proximity to a specific Class I area. The regulations addressing reasonably attributable visibility impairment are published in 40 CFR 51.300 through 51.307.

2. On July 1, 1999, we amended these regulations to address the second, more common, type of visibility impairment known as " regional haze." Regional haze is the result of the collective contribution of many sources over a broad region. The regional haze rule slightly modified 40 CFR 51.300 through 51.307,

including the addition of a few definitions in § 51.301, and added new § § 51.308 and 51.309.

E. What are the BART requirements in EPA's regional haze regulations?

1. In the July 1, 1999 rulemaking, we added a BART requirement 12 for regional haze. We amended the BART requirements in 2005.

You will find the BART requirements in 40 CFR 51.308( e).

Definitions of terms used in 40 CFR 51.308( e)( 1) are found in 40 CFR 51.301.

2. As we discuss in detail in these guidelines, the regional haze rule codifies and clarifies the BART provisions in the CAA.

The rule requires that States identify and list " BART eligible sources," that is, that States identify and list those sources that fall within the 26 source categories, were put in place during the 15 year window of time from 1962 to 1977, and have potential emissions greater than 250 tons per year. Once the State has identified the BART eligible sources, the next step is to identify those BART eligible sources that may " emit any air pollutant which may reasonably be anticipated to cause or contribute to any impairment of visibility." Under the rule, a source which fits this description is " subject to BART." For each source subject to BART, 40 CFR 308( e)( 1)( ii)( A) requires that States identify the level of control representing BART after considering the factors set out in CAA section 169A( g), as follows:

 States must identify the best system of continuous emission control technology for each source subject to BART taking into account the technology available, the costs of compliance, the energy and non air quality environmental 13 impacts of compliance, any pollution control equipment in use at the source, the remaining useful life of the source,

and the degree of visibility improvement that may be expected from available control technology.

3. After a State has identified the level of control representing BART ( if any), it must establish an emission limit representing BART and must ensure compliance with that requirement no later than 5 years after EPA approves the SIP.

States may establish design, equipment, work practice or other operational standards when limitations on measurement technologies make emission standards infeasible.

F. What is included in the guidelines?

1. The guidelines provide a process for making BART determinations that States can use in implementing the regional haze BART requirements on a source by source basis, as provided in 40 CFR 51.308( e)( 1). States must follow the guidelines in making BART determinations on a source by source basis for 750 megawatt ( MW) power plants but are not required to use the process in the guidelines when making BART determinations for other types of sources. However, we strongly encourage States to consider following the guidelines in establishing BART emission limitations for all other BART sources. We believe that adopting the approach set forth here, where practicable, will promote equitable application of the BART requirement to similar sources 14 in different States.

2. The BART analysis process, and the contents of these guidelines, are as follows:

( a) Identification of all BART eligible sources. Section II of these guidelines outlines a step by step process for identifying BART eligible sources.

( b) Identification of sources subject to BART. As noted above, sources " subject to BART" are those BARTeligible sources which " emit a pollutant which may reasonably be anticipated to cause or contribute to any impairment of visibility in any Class I area." We discuss considerations for identifying sources subject to BART in section III of the guidance.

( c) The BART determination process. For each source subject to BART, the next step is to conduct an analysis of emissions control alternatives. This step requires the identification of available, technically feasible retrofit technologies, and for each technology identified, an analysis of the cost of compliance, the energy and non air quality environmental impacts, and the degree of visibility improvement in affected Class I areas resulting from the use of the control technology. As part of the BART analysis, the State should also take into account the remaining useful life 1 In order to account for the possibility that BARTeligible sources could go unrecognized, we recommend that you adopt requirements placing a responsibility on source owners to self identify if they meet the criteria for BARTeligible sources.

15 of the source and any existing control technology present at the source. For each source, a " best system of continuous emission reduction" will be selected based upon these analyses. Procedures for the BART determination step are described in section IV of these guidelines.

( d) Emissions limits. States must establish enforceable limits, including a deadline for compliance, for each source subject to BART. Considerations related to these limits are discussed in section V of these guidelines.

G. Who is the target audience for the guidelines?

1. The guidelines are written primarily for the benefit of State, local and Tribal agencies, and describe a process for making the BART determinations and establishing the emission limitations that must be included in their SIPs or Tribal implementation plans ( TIPs). Throughout the guidelines, which are written in a question and answer format, we ask questions " How do I......?" and answer with phrases " you should...., you must...." The " you" means a State, local or Tribal agency conducting the analysis. 1 We have used this format to make the 16 guidelines simpler to understand, but we recognizethat agencies may prefer to require source owners to assume part of the analytical burden, and that there will be differences in how the supporting information is collected and documented. We also recognize that much of the data collection, analysis, and rule development may be performed by Regional Planning Organizations,

for adoption within each SIP or TIP.

2. The preamble to the 1999 regional haze rule discussed at length the issue of Tribal implementation of the requirements to submit a plan to address visibility. As explained there,

requirements related to visibility are among the programs for which Tribes may be determined eligible and receive authorization to implement under the " Tribal Authority Rule" (" TAR") ( 40 CFR 49.1 through 49.11). Tribes are not subject to the deadlines for submitting visibility implementation plans and may use a modular approach to CAA implementation. We believe there are very few BART eligible sources located on Tribal lands. Where such sources exist, the affected Tribe may apply for delegation of implementation authority for this rule, following the process set forth in the TAR.

H. Do EPA regulations require the use of these guidelines?

Section 169A( b) requires us to issue guidelines for States to follow in establishing BART emission limitations for fossilfuel fired power plants having a capacity in excess of 750 17 megawatts. This document is intended to fulfill that requirement, which is codified in 40 CFR 308( e)( 1)( ii)( B). The guidelines establish an approach to implementing the requirements of the BART provisions of the regional haze rule; we believe that these procedures and the discussion of the requirements of the regional haze rule and the CAA should be useful to the States.

We believe that adopting the approach set forth here, where practicable, will promote equitable application of the BART requirement to similar sources in different States. For sources other than 750 MW power plants, however, States retain the discretion to adopt approaches on a case by case basis that differ from the guidelines.

II. HOW TO IDENTIFY BART ELIGIBLE SOURCES This section provides guidelines on how to identify BARTeligible sources. A BART eligible source is an existing stationary source in any of 26 listed categories which meets criteria for startup dates and potential emissions.

A. What are the steps In identifying BART eligible sources?

Figure 1 shows the steps for identifying whether the source is a " BART eligible source:"

Step 1: Identify the emission units in the BART categories,

Step 2: Identify the start up dates of those emission units, and 18 Step 3: Compare the potential emissions to the 250 ton/ yr cutoff. 19 Figure 1. How to determine whether a source is BARTeligible

Step 1: Identify emission units in the BART categories Does the plant contain emissions units in one or more of the 26 source categories?

No

Stop

Yes

Proceed to Step 2 Step 2: Identify the start up dates of these emission units Do any of these emissions units meet the following two tests?

In existence on August 7, 1977 AND Began operation after August 7, 1962

No

Stop

Yes

Proceed to Step 3 20 Step 3: Compare the potential emissions from these emission units to the 250 ton/ yr cutoff Identify the " stationary source" that includes the emission units you identified in Step 2.

Add the current potential emissions from all the emission units identified in Steps 1 and 2 that are included within the " stationary source" boundary.

Are the potential emissions from these units 250 tons per year or more for any visibility impairing pollutant?

No

Stop

Yes

These emissions units comprise the " BART eligible source." 21 1. Step 1: Identify emission units in the BART categories 1. The BART requirement only applies to sources in specific categories listed in the CAA. The BART requirement does not apply to sources in other source categories, regardless of their emissions. The listed categories are:

( 1) Fossil fuel fired steam electric plants of more than 250 million British thermal units ( BTU) per hour heat input,

( 2) Coal cleaning plants ( thermal dryers),

( 3) Kraft pulp mills,

( 4) Portland cement plants,

( 5) Primary zinc smelters,

( 6) Iron and steel mill plants,

( 7) Primary aluminum ore reduction plants,

( 8) Primary copper smelters,

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

( 10) Hydrofluoric, sulfuric, and nitric acid plants,

( 11) Petroleum refineries,

( 12) Lime plants,

( 13) Phosphate rock processing plants,

( 14) Coke oven batteries,

( 15) Sulfur recovery plants,

( 16) Carbon black plants ( furnace process),

( 17) Primary lead smelters, 22 ( 18) Fuel conversion plants,

( 19) Sintering plants,

( 20) Secondary metal production facilities,

( 21) Chemical process plants,

( 22) Fossil fuel boilers of more than 250 million BTUs per hour heat input,

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

( 24) Taconite ore processing facilities,

( 25) Glass fiber processing plants, and ( 26) Charcoal production facilities.

2. Some plants may have emission units from more than one category, and some emitting equipment may fit into more than one category. Examples of this situation are sulfur recovery plants at petroleum refineries, coke oven batteries and sintering plants at steel mills, and chemical process plants at refineries. For Step 1, you identify all of the emissions units at the plant that fit into one or more of the listed categories. You do not identify emission units in other categories.

Example: A mine is collocated with an electric steam generating plant and a coal cleaning plant. You would identify emission units associated with the electric steam generating plant and the coal cleaning plant, because they are listed 23 categories, but not the mine, because coal mining is not a listed category.

3. The category titles are generally clear in describing the types of equipment to be listed. Most of the category titles are very broad descriptions that encompass all emission units associated with a plant site ( for example, " petroleum refining"

and " kraft pulp mills"). This same list of categories appears in the PSD regulations. States and source owners need not revisit any interpretations of the list made previously for purposes of the PSD program. We provide the following clarifications for a few of the category titles:

( 1) " Steam electric plants of more than 250 million BTU/ hr heat input." Because the category refers to " plants,"

we interpret this category title to mean that boiler capacities must should be aggregated to determine whether the 250 million BTU/ hr threshold is reached.

This definition includes only those plants that generate electricity for sale. Plants that cogenerate steam and electricity also fall within the definition of " steam electric plants". Similarly, combined cycle turbines are also considered " steam electric plants"

because such facilities incorporate heat recovery steam generators. Simple cycle turbines, in contrast, are not " steam electric plants" because these turbines 24 typically do not generate steam.

Example: A stationary source includes a steam electric plant with three 100 million BTU/ hr boilers.

Because the aggregate capacity exceeds 250 million BTU/ hr for the " plant," these boilers would be identified in Step 2.

( 2) " Fossil fuel boilers of more than 250 million BTU/ hr heat input." We interpret this category title to cover only those boilers that are individually greater than 250 million BTU/ hr. However, an individual boiler smaller than 250 million BTU/ hr should be subject to BART if it is part of a process description at a plant that is in a different BART category   for example, a boiler at a chemical process plant. In general, if the process uses any by product of the boiler, then the boiler is integral to the process, and should be considered to be part of the process description.

Also, you should consider a multi fuel boiler to be a " fossil fuel boiler" if it burns any amount of fossil fuel. You may take federally enforceable operational limits into account in determining whether a multi fuel boiler's fossil fuel capacity exceeds 250 million Btu/ hr.

( 3) " Petroleum storage and transfer facilities with a 25 capacity exceeding 300,000 barrels." The 300,000 barrel cutoff refers to total facility wide tank capacity for tanks that were put in place within the 1962 1977 time period, and includes gasoline and other petroleum derived liquids.

( 4) " Phosphate rock processing plants." This category descriptor is broad, and includes all types of phosphate rock processing facilities, including elemental phosphorous plants as well as fertilizer production plants.

( 5) Charcoal production facilities." We interpret this category to include charcoal briquet manufacturing and activated carbon production.

( 6) " Chemical process plants" and pharmaceutical manufacturing. Consistent with past policy, we interpret the category " chemical process plants" to include those facilities within the 2 digit Standard Industrial Classification ( SIC) code 28. Accordingly,

we interpret the term " chemical process plants" to include pharmaceutical manufacturing facilities.

( 7) " Secondary metal production." We interpret this category to include nonferrous metal facilities included within SIC code 3341, and secondary ferrous metal facilities that we also consider to be included 26 within the category " iron and steel mill plants."

( 8) " Primary aluminum ore reduction." We interpret this category to include those facilities covered by 40 CFR 60.190, the new source performance standard ( NSPS) for primary alumimum ore reduction plants. This definition is also consistent with the definition at 40 CFR 63.840.

2. Step 2: Identify the start up dates of the emission units 1. Emissions units listed under Step 1 are BART eligible only if they were " in existence" on August 7, 1977 but were not " in operation" before August 7, 1962.

What does " in existence on August 7, 1977" mean?

2. The regional haze rule defines " in existence" to mean 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 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." 40 CFR 51.301.

As this definition is essentially identical to the definition of 27 " commence construction" as that term is used in the PSD regulations, the two terms mean the same thing. See 40 CFR 51.165( a)( 1)( xvi) and 40 CFR 52.21( b)( 9). Under this definition,

an emissions unit could be " in existence" even if it did not begin operating until several years after 1977 .

Example: The owner of a source obtained all necessary permits in early 1977 and entered into binding construction agreements in June 1977. Actual onsite construction began in late 1978, and construction was completed in mid 1979. The source began operating in September 1979. The emissions unit was " in existence" as of August 7,

1977.

Major stationary sources which commenced construction AFTER August 7, 1977 ( i. e., major stationary sources which were not " in existence" on August 7, 1977) were subject to new source review ( NSR) under the PSD program. Thus, the August 7, 1977 " in existence" test is essentially the same thing as the identification of emissions units that were grandfathered from the NSR review requirements of the 1977 CAA amendments.

3. Sources are not BART eligible if the only change at the plant during the relevant time period was the addition of pollution controls. For example, if the only change at a copper smelter during the 1962 through 1977 time period was the addition 28 of acid plants for the reduction of SO2 emissions, these emission controls would not by themselves trigger a BART review.

What does " in operation before August 7, 1962" mean?

An emissions unit that meets the August 7, 1977 " in existence" test is not BART eligible if it was in operation before August 7, 1962. " In operation" is defined as " engaged in activity related to the primary design function of the source."

This means that a source must have begun actual operations by August 7, 1962 to satisfy this test.

Example: The owner or operator entered into binding agreements in 1960. Actual on site construction began in 1961,

and construction was complete in mid 1962. The source began operating in September 1962. The emissions unit was not " in operation" before August 7, 1962 and is therefore subject to BART.

What is a " reconstructed source?"

1. Under a number of CAA programs, an existing source which is completely or substantially rebuilt is treated as a new source.

Such " reconstructed" sources are treated as new sources as of the time of the reconstruction. Consistent with this overall approach to reconstructions, the definition of BART eligible facility ( reflected in detail in the definition of " existing stationary facility") includes consideration of sources that were in operation before August 7, 1962, but were reconstructed during 29 the August 7, 1962 to August 7, 1977 time period.

2. Under the regional haze regulations at 40 CFR 51.301, a reconstruction has taken place if " the fixed capital cost of the new component exceeds 50 percent of the fixed capital cost of a comparable entirely new source." The rule also states that "[ a] ny 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." "[ T] he provisions of § § 60.15( f)( 1)

through ( 3)" refers to the general provisions for New Source Performance Standards ( NSPS). Thus, the same policies and procedures for identifying reconstructed " affected facilities"

under the NSPS program must also be used to identify reconstructed " stationary sources" for purposes of the BART requirement.

3. You should identify reconstructions on an emissions unit basis, rather than on a plantwide basis. That is, you need to identify only the reconstructed emission units meeting the 50 percent cost criterion. You should include reconstructed emission units in the list of emission units you identified in Step 1. You need consider as possible reconstructions only those emissions units with the potential to emit more than 250 tons per year of any visibility impairing pollutant.

4. The " in operation" and " in existence" tests apply to reconstructed sources. If an emissions unit was reconstructed 30 and began actual operation before August 7, 1962, it is not BARTeligible Similarly, any emissions unit for which a reconstruction " commenced" after August 7, 1977, is not BARTeligible

How are modifications treated under the BART provision?

1. The NSPS program and the major source NSR program both contain the concept of modifications. In general, the term " modification" refers to any physical change or change in the method of operation of an emissions unit that results in an increase in emissions.

2. The BART provision in the regional haze rule contains no explicit treatment of modifications or how modified emissions units, previously subject to the requirement to install best available control technology ( BACT), lowest achievable emission rate ( LAER) controls, and/ or NSPS are treated under the rule. As the BART requirements in the CAA do not appear to provide any exemption for sources which have been modified since 1977, the best interpretation of the CAA visibility provisions is that a subsequent modification does not change a unit's construction date for the purpose of BART applicability. Accordingly, if an emissions unit began operation before 1962, it is not BARTeligible if it was modified between 1962 and 1977, so long as the modification is not also a " reconstruction." On the other hand,

an emissions unit which began operation within the 1962 1977 time 31 window, but was modified after August 7, 1977, is BART eligible.

We note, however, that if such a modification was a major modification that resulted in the installation of controls, the State will take this into account during the review process and may find that the level of controls already in place are consistent with BART.

3. Step 3: Compare the potential emissions to the 250 ton/ yr cutoff The result of Steps 1 and 2 will be a list of emissions units at a given plant site, including reconstructed emissions units, that are within one or more of the BART categories and that were placed into operation within the 1962 1977 time window.

The third step is to determine whether the total emissions represent a current potential to emit that is greater than 250 tons per year of any single visibility impairing pollutant.

Fugitive emissions, to the extent quantifiable, must be counted.

In most cases, you will add the potential emissions from all emission units on the list resulting from Steps 1 and 2. In a few cases, you may need to determine whether the plant contains more than one " stationary source" as the regional haze rule defines that term, and as we explain further below.

What pollutants should I address?

Visibility impairing pollutants include the following:

( 1) Sulfur dioxide ( SO2), 32 ( 2) Nitrogen oxides ( NOx), and ( 3) Particulate matter.

You may use PM10 as an indicator for particulate matter in this intial step. [ Note that we do not recommend use of total suspended particulates ( TSP) as in indicator for particulate matter.] As emissions of PM10 include the components of PM2.5 as a subset, there is no need to have separate 250 ton thresholds for PM10 and PM2.5; 250 tons of PM10 represents at most 250 tons of PM2.5, and at most 250 tons of any individual particulate species such as elemental carbon, crustal material, etc.

However, if you determine that a source of particulate matter is BART eligible, it will be important to distinguish between the fine and coarse particle components of direct particulate emissions in the remainder of the BART analysis,

including for the purpose of modeling the source's impact on visibility. This is because although both fine and coarse particulate matter contribute to visibility impairment, the long range transport of fine particles is of particular concern in the formation of regional haze. Thus, for example,

air quality modeling results used in the BART 2 Fine particles: Overview of Atmospheric Chemistry, Sources of Emissions, and Ambient Monitoring Data, Memorandum to Docket OAR 2002 0076, April 1, 2005.

33 determination will provide a more accurate prediction of a source's impact on visibility if the inputs into the model account for the relative particle size of any directly emitted particulate matter ( i. e. PM10 vs. PM2.5).

You should exercise your best judgement in deciding whether the following pollutants impair visibility in an area:

( 4) Volatile organic compounds ( VOC), and ( 5) Ammonia and ammonia compounds.

In deciding whether VOC or ammonia emissions from a source are likely to have an impact on visibility in an area, you should use your best judgement in making these case by case assessments. Certain types of VOC emissions, for example, are more likely to form secondary organic aerosols than others. 2 Similarly, controlling ammonia emissions in some areas may not have a significant impact on visibility. You need not provide a formal showing of each judgement that a source of VOC or ammonia emissions is not subject to BART review. Because air quality modeling may 34 not be feasible for individual sources of VOC or ammonia, you should also exercise your best judgement in assessing the degree of visibility impacts due to emisssions of VOC and emissions of ammonia or ammonia compounds. You should fully document the basis for judging that a VOC or ammonia source merits BART review, including your assessment of the source's contribution to visibility impairment.

What does the term " potential" emissions mean?

The regional haze rule defines potential to emit as follows:

" 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. 3 Note: Most of these terms and definitions are the same for regional haze and the 1980 visibility regulations. For the regional haze rule we use the term " BART eligible 35 The definition of " potential to emit" means that a source which actually emits less than 250 tons per year of a visibility impairing pollutant is BART eligible if its emissions would exceed 250 tons per year when operating at its maximum capacity given its physical and operational design ( and considering all federally enforceable permit limits.)

Example: A source, while operating at one fourth of its capacity, emits 75 tons per year of SO2.

If it were operating at 100 percent of its maximum capacity, the source would emit 300 tons per year. Because under the above definition such a source would have " potential" emissions that exceed 250 tons per year, the source ( if in a listed category and built during the 1962 1977 time window)

would be BART eligible.

How do I identify whether a plant has more than one " stationary source?"

1. The regional haze rule, in 40 CFR 51.301, defines a stationary source as a " building, structure, facility or installation which emits or may emit any air pollutant." 3 source" rather than " existing stationary facility" to clarify that only a limited subset of existing stationary sources are subject to BART.

36 The rule further defines " building, structure or facility"

as:

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 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).

2. In applying this definition, it is necessary to determine which facilities are located on " contiguous or adjacent properties." Within this contiguous and adjacent area, it is also necessary to group those emission units that are under " common control." We note that these plant boundary issues and " common control" issues are very similar to those already addressed in implementation of the title V operating permits program and in NSR. 4 We recognize that we are in a transition period from the use of the SIC system to a new system called the North American Industry Classification System ( NAICS). For purposes of identifying BART eligible sources, you may use either 2 digit SICS or the equivalent in the NAICS system.

5 Note: The concept of support facility used for the NSR program applies here as well. Support facilities, that is facilities that convey, store or otherwise assist in the production of the principal product, must be grouped with primary facilities even when the facilities fall within separate SIC codes. For purposes of BART reviews, however, such support facilities ( a) must be within one of the 26 listed source categories and ( b) must have been in existence as of August 7, 1977, and ( c) must not have been in operation as of August 7, 1962.

37 3. For emission units within the " contiguous or adjacent"

boundary and under common control, you must group emission units that are within the same industrial grouping ( that is,

associated with the same 2 digit SIC code) in order to define the stationary source. 4 For most plants on the BART source category list, there will only be one 2 digit SIC that applies to the entire plant. For example, all emission units associated with kraft pulp mills are within SIC code 26, and chemical process plants will generally include emission units that are all within SIC code 28. The " 2

digit SIC test" applies in the same way as the test is applied in the major source NSR programs. 5 4. For purposes of the regional haze rule, you must group emissions from all emission units put in place within the 1962 1977 time period that are within the 2 digit SIC code, 38 even if those emission units are in different categories on the BART category list.

Examples: A chemical plant which started operations within the 1962 to 1977 time period manufactures hydrochloric acid ( within the category title " Hydrochloric, sulfuric, and nitric acid plants") and various organic chemicals ( within the category title " chemical process plants"), and has onsite an industrial boiler greater than 250 million BTU/ hour. All of the emission units are within SIC code 28 and, therefore, all the emission units are considered in determining BART eligibility of the plant. You sum the emissions over all of these emission units to see whether there are more than 250 tons per year of potential emissions.

A steel mill which started operations within the 1962 to 1977 time period includes a sintering plant, a coke oven battery, and various other emission units. All of the emission units are within SIC code 33. You sum the emissions over all of these emission units to see whether there are more than 250 39 tons per year of potential emissions.

4. Final Step: Identify the emissions units and pollutants that constitute the BART eligible source If the emissions from the list of emissions units at a stationary source exceed a potential to emit of 250 tons per year for any visibility impairing pollutant, then that collection of emissions units is a BART eligible source.

Example: A stationary source comprises the following two emissions units, with the following potential emissions:

Emissions unit A 200 tons/ yr SO2 150 tons/ yr NOX 25 tons/ yr PM Emissions unit B 100 tons/ yr SO2 75 tons/ yr NOX 10 tons/ yr PM For this example, potential emissions of SO2 are 300 tons/ yr,

which exceeds the 250 tons/ yr threshold. Accordingly, the entire " stationary source", that is, emissions units A and B, may be subject to a BART review for SO2, NOX, and PM, even though the potential emissions of PM and NOx at each emissions unit are less than 250 tons/ yr each.

Example: The total potential emissions, obtained by adding the potential emissions of all emission units in a 40 listed category at a plant site, are as follows:

200 tons/ yr SO2 150 tons/ yr NOX 25 tons/ yr PM Even though total emissions exceed 250 tons/ yr, no individual regulated pollutant exceeds 250 tons/ yr and this source is not BART eligible.

Can States establish de minimis levels of emissions for pollutants at BART eligible sources?

In order to simplify BART determinations, States may choose to identify de minimis levels of pollutants at BARTeligible sources ( but are not required to do so). De minimis values should be identified with the purpose of excluding only those emissions so minimial that they are unlikely to contribute to regional haze. Any de minimis values that you adopt must not be higher than the PSD applicability levels: 40 tons/ yr for SO2, NOX and VOC, and 15 tons/ yr for PM1 0. These de minimis levels may only be applied on a plant wide basis.

III. HOW TO IDENTIFY SOURCES " SUBJECT TO BART"

[ PLACEHOLDER FOR NEW SECTION III ] 41 IV. THE BART DETERMINATION: ANALYSIS OF BART OPTIONS This section describes the process for the analysis of control options for sources subject to BART.

A. What Factors Must I Address in the BART review?

The visibility regulations define BART as follows:

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... [ a BART  eligible source]. The emission limitation must be established, on a case

bycase 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.

The BART analysis identifies the best system of continuous emission reduction taking into account:

( 1) the available retrofit control options,

( 2) any pollution control equipment in use at the source ( which affects the availability of options and their 42 impacts),

( 3) the costs of compliance with control options,

( 4) the remaining useful life of the facility ( which as we will discuss below, is an integral part of the cost analysis),

( 5) the energy and non air quality environmental impacts of control options ( 6) the visibility impacts analysis.

B. How does a BART Review Compare to a BACT Review Under the PSD Program?

The process for a BART analysis is similar in many ways to the BACT review as described in the New Source Review Workshop Manual ( Draft, October 1990). However, BART reviews differ in certain respects from the BACT review described in the NSR Draft Manual. First, because all BART reviews apply to existing sources, the available controls and the impacts of those controls may differ from source to source. Second, the CAA requires you to take slightly different factors into account in determining BART and BACT. In a BACT analysis, the permitting authority must consider the " energy, environmental and economic impacts and other costs" associated with a control technology in making its determination. In a BART analysis, on the other hand, the State must take into account the " cost of compliance, the remaining useful life of the source, the energy and nonair quality 43 environmental impacts of compliance, any existing pollution control technology in use at the source, and the degree of improvement in visibility from the use of such technology" in making its determination. Because of the differences in terminology, the BACT review process tends to encompass a broader range of factors. For example, the term " environmental impacts"

in the BACT definition is more broad than the term " nonair quality environmental impacts" used in the BART definition.

Accordingly, there is no requirement in the BART analysis to evaluate adverse air quality impacts of control alternatives such as the relative impacts on hazardous air pollutants, although you may wish to do so. Finally, for the BART analysis, there is no minimum level of control required, while any BACT emission limitation must be at least as stringent as any NSPS that applies to the source.

B. What is the Scope of the BART Review?

Once you determine that a source is subject to BART for a particular pollutant, then for each affected emission unit, you must establish BART for that pollutant. The BART determination must address air pollution control measures for each emissions unit or pollutant emitting activity subject to review.

Example: Plantwide emissions from emission units within the listed categories that began operation within the " time 6 That is, emission units that were in existence on August 7, 1977 and which began actual operation on or after August 7, 1962.

44 window" for BART6 are 300 tons/ yr of NOx, 200 tons/ yr of SO2,

and 150 tons/ yr of primary particulate. Emissions unit A emits 200 tons/ yr of NOx, 100 tons/ yr of SO2, and 100 tons/ yr of primary particulate. Other emission units, units B through H, which began operating in 1966, contribute lesser amounts of each pollutant. For this example, a BART review is required for NOx, SO2, and primary particulate, and control options must be analyzed for units B through H as well as unit A.

D. How Does a BART Review Relate to Maximum Achievable Control Technology ( MACT) Standards Under CAA Section 112, or to Other Emission Limitations Required under the CAA?

For VOC and PM sources subject to MACT standards, States may streamline the analysis by including a discussion of the MACT controls and whether any major new technologies have been developed subsequent to the MACT standards. We believe that there are many VOC and PM sources that are well controlled because they are regulated by the MACT standards, which EPA developed under CAA section 112. For a few MACT standards, this may also be true for SO2. Any source subject to MACT standards must meet a level that is as stringent as the best controlled 12 percent of sources in the industry. Examples of these hazardous 45 air pollutant sources which effectively control VOC and PM emissions include ( among others) secondary lead facilities,

organic chemical plants subject to the hazardous organic NESHAP ( HON), pharmaceutical production facilities, and equipment leaks and wastewater operations at petroleum refineries. We believe that, in many cases, it will be unlikely that States will identify emission controls more stringent than the MACT standards without identifying control options that would cost many thousands of dollars per ton. Unless there are new technologies subsequent to the MACT standards which would lead to costeffective increases in the level of control, you may rely on the MACT standards for purposes of BART.

We believe that the same rationale also holds true for emissions standards developed for municipal waste incinerators under CAA section 111( d), and for many NSR/ PSD determinations and NSR/ PSD settlement agreements. However, we do not believe that technology determinations from the 1970s or early 1980s,

including new source performance standards ( NSPS), should be considered to represent best control for existing sources, as best control levels for recent plant retrofits have exceeded these older levels.

Where you are relying on MACTthese standards to achieve a BART level of control, you must should provide the public with a discussion of whether any new technologies have subsequently 7 In identifying " all" options, you must identify the most stringent option and a reasonable set of options for analysis that reflects a comprehensive list of available technologies. It is not necessary to list all permutations of available control levels that exist for a given technology    the list is complete if it includes the maximum level of control each technology is capable of achieving.

46 become available. how you have reached the conclusion that it is appropriate to rely on MACT standards or BACT or LAER limits, and a discussion of whether any new technologies are available subsequent to the date the MACT standrads were published.

D. What are the Five Basic Steps of a Case by Case BART Analysis?

The five steps are:

STEP 1  Identify All7 Available Retrofit Control Technologies,

STEP 2 Eliminate Technically Infeasible Options,

STEP 3 Rank Evaluate Control Effectiveness of Remaining Control Technologies By Control Effectiveness,

STEP 4 Evaluate Impacts and Document the Results, and STEP 5   Evaluate Visibility Impacts.

1. STEP 1: How do I identify all available retrofit emission control techniques?

1. Available retrofit control options are those air pollution control technologies with a practical potential for application 8 In EPA's 1980 BART guidelines for reasonably attributable visibility impairment, we concluded that NSPS standards generally, at that time, represented the best 47 to the emissions unit and the regulated pollutant under evaluation. Air pollution control technologies can include a wide variety of available methods, systems, and techniques for control of the affected pollutant. Available air pollution control technologies can include technologies employed outside of the United States that have been successfully demonstrated in practice on full scale operations, particularly those that have been demonstrated as retrofits to existing sources. Technologies required as BACT or LAER are available for BART purposes and must be included as control alternatives. The control alternatives shouldcan include not only existing controls for the source category in question, but also take into account technology transfer of controls that have been applied to similar source categories and gas streams. Technologies which have not yet been applied to ( or permitted for) full scale operations need not be considered as available; we do not expect the source owner to purchase or construct a process or control device that has not already been demonstrated in practice.

2. Where a NSPS exists for a source category ( which is the case for most of the categories affected by BART), you should include a level of control equivalent to the NSPS as one of the control options. 8 The NSPS standards are codified in 40 CFR part 60. We level sources could install as BART. In the 20 year period since this guidance was developed, there have been advances in SO2 control technologies as well as technologies for the control of other pollutants, confirmed by a number of recent retrofits at Western power plants. Accordingly, EPA no longer concludes that the NSPS level of controls automatically represents " the best these sources can install." While it is possible that a detailed analysis of the BART factors could result in the selection of a NSPS level of control, you should reach this conclusion only after considering the full range of control options.

48 note that there are situations where NSPS standards do not require the most stringent level of available control for all sources within a category. For example, post combustion NOx controls ( the most stringent controls for stationary gas turbines) are not required under subpart GG of the NSPS for Stationary Gas Turbines. However, such controls must still be considered available technologies for the BART selection process.

3. Potentially applicable retrofit control alternatives can be categorized in three ways.

! Pollution prevention: use of inherently lower emitting processes/ practices, including the use of control techniques ( e. g. low NOx burners) materials and production processes and work practices that prevent emissions and result in lower " production specific"

emissions ( note that it is not our intent to direct States to switch fuel forms, e. g. from coal to gas),

! Use of ( and where already in place, improvement in the performance of) add on controls, such as scrubbers, 49 fabric filters, thermal oxidizers and other devices that control and reduce emissions after they are produced, and ! Combinations of inherently lower emitting processes and add on controls. Example: for a gas fired turbine, a combination of combustion controls ( an inherently lower emitting process) and post combustion controls such as selective catalytic reduction ( add on) may be available to reduce NOx emissions.

4. For the BART review, you should consider potentially applicable control techniques from all three categories. You should consider lower polluting processes based on demonstrations from facilities manufacturing identical or similar products using identical or similar raw materials or fuels. Add on controls, on the other hand, should be considered based on the physical and chemical characteristics of the pollutant bearing emission stream. Thus, candidate add on controls may have been applied to a broad range of emission unit types that are similar, insofar as emissions characteristics, to the emissions unit undergoing BART review.

4. In the course of the BART review, one or more of the available control options may be eliminated from consideration because they are demonstrated to be technically infeasible or to have unacceptable energy, cost, or non air quality environmental 9 Because BART applies to existing sources, we recognize that there will probably be far fewer opportunities to consider inherently lower emitting processes than may be available for NSR.

50 impacts on a case by case ( or site specific) basis. However, at the outset, you should initially identify all control options with potential application to the emissions unit under review.

5. We do not consider BART as a requirement to redesign the source when considering available control alternatives. For example, where the source subject to BART is a coal fired electric generator, we do not require the BART analysis to consider building a natural gas fired electric turbine although the turbine may be inherently less polluting on a per unit basis.

7. In some cases, retrofit design changes may be available for making a given production process or emissions unit inherently less polluting. 9 ( Example: use of low NOX burners). In such cases, the ability of design considerations to make the process inherently less polluting must be considered as a control alternative for the source.

8. Combinations of inherently lower polluting processes/ practices ( or a process made to be inherently less polluting) and add on controls could possibly yield more effective means of emissions control than either approach alone.

Therefore, the option to use an inherently lower polluting process does not, in and of itself, mean that no additional 51 add on controls need to be included in the BART analysis. These combinations should be identified in Step 1 for evaluation in subsequent steps. ( Example: use of low NOX burner and add on SCR for NOX control).

6. For emission units subject to a BART review, there will often be control measures or devices already in place. For such emission units, it is important to include control options that involve improvements to existing controls, and not to limit the control options only to those measures that involve a complete replacement of control devices.

Example: For a power plant with an existing wet scrubber,

the current control efficiency is 66 percent.

Part of the reason for the relatively low control efficiency is that 22 percent of the gas stream bypasses the scrubber. A BART review identifies options for improving the performance of the wet scrubber by redesigning the internal components of the scrubber and by eliminating or reducing the percentage of the gas stream that bypasses the scrubber. Four control options are identified:

( 1) 78 percent control based upon improved scrubber performance while maintaining the 22 percent bypass, ( 2) 83 percent control based upon improved scrubber performance while reducing the 52 bypass to 15 percent, ( 3) 93 percent control based upon improving the scrubber performance while eliminating the bypass entirely, ( this option results in a " wet stack" operation in which the gas leaving the stack is saturated with water) and ( 4) 93 percent as in option 3, with the addition of an indirect reheat system to reheat the stack gas above the saturation temperature. You must consider each of these four options in a BART analysis for this source.

7. You are expected to identify all potentially applicable retrofit control technologyies that represent the full range of demonstrated alternatives. Examples of general information sources to consider include:

! The EPA's Clean Air Technology Center, which includes the RACT/ BACT/ LAER Clearinghouse ( RBLC);

! State and Local Best Available Control Technology Guidelines  many agencies have online information   for example South Coast Air Quality Management District,

Bay Area Air Quality Management District, and Texas Natural Resources Conservation Commission;

! Control technology vendors;

! Federal/ State/ Local NSR permits and associated inspection/ performance test reports; 53 ! Environmental consultants;

! Technical journals, reports and newsletters, air pollution control seminars; and ! The EPA's NSR bulletin board

http:// www. epa. gov/ ttn/ nsr;

! Department of Energy's Clean Coal Program  technical reports;

! The NOx Control Technology " Cost Tool"  Clean Air Markets Division web page

http:// www. epa. gov/ airmarkets/ arp/ nox/ controltech. html;

! Performance of selective catalytic reduction on coalfired steam generating units  final report. OAR/ ARD,

June 1997 ( also available at http:// www. epa. gov/ airmarkets/ arp/ nox/ controltech. html)

;

! Cost estimates for selected applications of NOx control technologies on stationary combustion boilers. OAR/ ARD June 1997. ( Docket for NOx SIP Call, A 96 56, item IIA 03);

! Investigation of performance and cost of NOx controls as applied to group 2 boilers. OAR/ ARD, August 1996.

( Docket for Phase II NOX rule, A 95 28, item IV A 4);

! Controlling SO2 Emissions: A Review of Technologies.

EPA 600/ R 00 093, USEPA/ ORD/ NRMRL, October 2000; and 54 ! The OAQPS Control Cost Manual.

You shouldare expected to compile appropriate information from all availablethese information sources, and you should ensure that the resulting list of control alternatives is complete and comprehensive.

8. There may be situations where a specific set of units within a fenceline constitutes the logical set to which controls would apply, and that set of units may or may not all be BART eligible.

( For example, some units in that set may not have been constructed between 1962 and 1977.) You should consider allowing sources to " average" emissions across any set of BART eligible emission units within a fenceline, so long as the emission reductions from each pollutant being controlled for BART would be greater than those reductions that would be obtained by simply controlling each of the BART eligible units that constitute BARTeligible source.

9. If you find that a BART source has controls already in place which are the most stringent controls available ( note that this means that all possible improvements to any control devices have been made), then it is not necessary to comprehensively complete each following step of the BART analysis in this section. As long these most stringent controls available are made federally enforceable for the purpose of implementing BART for that source,

you may skip the remaining analyses in this section, including 55 the visibility analysis in step 5. Likewise, if a source commits to a BART determination that consists of the most stringent controls available, then there is no need to complete the remaining analyses in this section.

2. STEP 2: How do I determine whether the options identified in Step 1 are technically feasible?

In Step 2, you evaluate the technical feasibility of the control options you identified in Step 1. You should clearly document a demonstration of technical infeasibility and should show, based on physical, chemical, and engineering principles,

that technical difficulties would preclude the successful use of the control option on the emissions unit under review. You may then eliminate such technically infeasible control options from further consideration in the BART analysis.

In general, what do we mean by technical feasibility?

Control technologies are technically feasible if either ( 1) they have been installed and operated successfully for the type of source under review, or ( 2) the technology could be applied to the source under review. Two key concepts are important in determining whether a technology could be applied: " availability" and " applicability." As explained in more detail below, a technology is considered " available"

if the source owner may obtain it through commercial channels, or it is otherwise available within the common 56 sense meaning of the term. An available technology is " applicable" if it can reasonably be installed and operated on the source type under consideration. A technology that is available and applicable is technically feasible.

What do we mean by " available" technology?

1. The typical stages for bringing a control technology concept to reality as a commercial product are:

! concept stage;

! research and patenting;

! bench scale or laboratory testing;

! pilot scale testing;

! licensing and commercial demonstration; and ! commercial sales.

2. A control technique is considered available, within the context presented above, if it has reached the licensing and commercial sales stage of development. Similarly, we do not expect a source owner to conduct extended trials to learn how to apply a technology on a totally new and dissimilar source type. Consequently, you would not consider technologies in the pilot scale testing stages of development as " available" for purposes of BART review.

3. Commercial availability by itself, however, is not necessarily a sufficient basis for concluding a technology to be applicable and therefore technically feasible. 57 Technical feasibility, as determined in Step 2, also means a control option may reasonably be deployed on or " applicable"

to the source type under consideration.

Because a new technology may become available at various points in time during the BART analysis process, we believe that guidelines are needed on when a technology must be considered. For example, a technology may become available during the public comment period on the State's rule development process. Likewise, it is possible that new technologies may become available after the close of the State's public comment period and before submittal of the SIP to EPA, or during EPA's review process on the SIP submittal. In order to provide certainty in the process,

all technologies should be considered if available before the close of the State's public comment period. You need not consider technologies that become available after this date. As part of your analysis, you should consider any technologies brought to your attention in public comments.

If you disagree with public comments asserting that the technology is available, you should provide an explanation for the public record as to the basis for your conclusion.

What do we mean by " applicable" technology?

You need to exercise technical judgment in determining whether a control alternative is applicable to the source 58 type under consideration. In general, a commercially available control option will be presumed applicable if it has been or is soon to be deployed ( e. g., is specified in a permit) on the same or a similar source type. Absent a showing of this type, you evaluate technical feasibility by examining the physical and chemical characteristics of the pollutant bearing gas stream, and comparing them to the gas stream characteristics of the source types to which the technology had been applied previously. Deployment of the control technology on a new or existing source with similar gas stream characteristics is generally a sufficient basis for concluding the technology is technically feasible barring a demonstration to the contrary as described below.

What type of demonstration is required if I conclude that an option is not technically feasible?

1. Where you assert that a control option identified in Step 1 is technically infeasible, you should make a factual demonstration that the option is commercially unavailable,

or that unusual circumstances preclude its application to a particular emission unit. Generally, such a demonstration involves an evaluation of the characteristics of the pollutant bearing gas stream and the capabilities of the technology. Alternatively, a demonstration of technical infeasibility may involve a showing that there are 59 unresolvable technical difficulties with applying the control to the source ( e. g., size of the unit, location of the proposed site, or operating problems related to specific circumstances of the source). Where the resolution of technical difficulties is a matter of cost, you should consider the technology to be technically feasible. The cost of a control alternative is considered later in the process.

2. The determination of technical feasibility is sometimes influenced by recent air quality permits. In some cases, an air quality permit may require a certain level of control,

but the level of control in a permit is not expected to be achieved in practice ( e. g., a source has received a permit but the project was canceled, or every operating source at that permitted level has been physically unable to achieve compliance with the limit). Where this is the case, you should provide supporting documentation showing why such limits are not technically feasible, and, therefore, why the level of control ( but not necessarily the technology) may be eliminated from further consideration. However, if there is a permit requiring the application of a certain technology or emission limit to be achieved for such technology ( especially as a retrofit for an existing emission unit),

this usually is sufficient justification for you to assume 60 the technical feasibility of that technology or emission limit.

3. Physical modifications needed to resolve technical obstacles do not, in and of themselves, provide a justification for eliminating the control technique on the basis of technical infeasibility. However, you may consider the cost of such modifications in estimating costs. This,

in turn, may form the basis for eliminating a control technology ( see later discussion).

4. Vendor guarantees may provide an indication of commercial availability and the technical feasibility of a control technique and could contribute to a determination of technical feasibility or technical infeasibility, depending on circumstances. However, we do not consider a vendor guarantee alone to be sufficient justification that a control option will work. Conversely, lack of a vendor guarantee by itself does not present sufficient justification that a control option or an emissions limit is technically infeasible. Generally, you should make decisions about technical feasibility based on chemical, and engineering analyses ( as discussed above), in conjunction with information about vendor guarantees.

5. A possible outcome of the BART procedures discussed in these guidelines is the evaluation of multiple control 61 technology alternatives which result in essentially equivalent emissions. It is not our intent to encourage evaluation of unnecessarily large numbers of control alternatives for every emissions unit. Consequently, you should use judgment in deciding on those alternatives for which you will conduct the detailed impacts analysis ( Step 4 below). For example, if two or more control techniques result in control levels that are essentially identical,

considering the uncertainties of emissions factors and other parameters pertinent to estimating performance, you may evaluate only the less costly of these options. You should narrow the scope of the BART analysis in this way, only if there is a negligible difference in emissions and energy and non air quality environmental impacts between control alternatives.

3. STEP 3: How do I develop a ranking of the evaluate technically feasible alternatives?

Step 3 involves ranking all the technically feasible control alternatives identified in Step 2. For the pollutant and emissions unit under review, you rank the control alternatives from the most to the least effective in terms of emission reduction potential.

Two key issues that must be addressed in this process include: 62 ( 1) Making sure that you express the degree of control using a metric that ensures an " apples to apples" comparison of emissions performance levels among options, and ( 2) Giving appropriate treatment and consideration of control techniques that can operate over a wide range of emission performance levels.

What are the appropriate metrics for comparison?

This issue is especially important when you compare inherently lower polluting processes to one another or to add on controls. In such cases, it is generally most effective to express emissions performance as an average steady state emissions level per unit of product produced or processed.

Examples of common metrics:

! pounds of SO2 emissions per million Btu heat input,

and ! pounds of NOx emissions per ton of cement produced.

How do I evaluate control techniques with a wide range of emission performance levels?

1. Many control techniques, including both add on controls and inherently lower polluting processes, can perform at a wide range of levels. Scrubbers and high and low efficiency electrostatic precipitators ( ESPs) are two of the many examples of such control techniques that can perform at a wide range of levels. It is not our intent to require 63 analysis of each possible level of efficiency for a control technique, as such an analysis would result in a large number of options. It is important, however, that in analyzing the technology you take into account the most stringent emission control level that the technology is capable of achieving. You should use the most recent regulatory decisions and performance data ( e. g.,

manufacturer's data, engineering estimates and the experience of other sources) to identify an emissions performance level or levels to evaluate.

2. In assessing the capability of the control alternative,

latitude exists to consider any special circumstances pertinent to the specific source under review, or regarding the prior application of the control alternative. However,

you must document the basis for choosing the alternate level ( or range) of control in the BART analysis. Without a showing of differences between the source and other sources that have achieved more stringent emissions limits, you should conclude that the level being achieved by those other sources is representative of the achievable level for the source being analyzed.

3. You may encounter cases where you may wish to evaluate other levels of control in addition to the most stringent level for a given device. While you must consider the most 64 stringent level as one of the control options, you may consider less stringent levels of control as additional options. This would be useful, particularly in cases where the selection of additional options would have widely varying costs and other impacts.

4. Finally, we note that for retrofitting existing sources in addressing BART, you should consider ways to improve the performance of existing control devices, particularly when a control device is not achieving the level of control that other similar sources are achieving in practice with the same device. For example, you should strongly consider requiring those sources with electrostatic precipitators ( ESPs) performing below currently achievable levels to significantly improve their performance.

How do I rank the control options?

After determining the emissions performance levels ( using appropriate metrics of comparison) for each control technology option identified in Step 2, you establish a list that identifies the most stringent control technology option and its emissions performance level, as well as any other control options identified, along with their respective emissions performance levels. You should do this for each pollutant and for each emissions unit ( or grouping of similar units) subject to a BART analysis. 65 4. STEP 4: For a BART review, what impacts am I expected to must Icalculate and report? What methods does EPA recommend for the impacts analysis?

After you identify and rank the available and technically feasible control technology options, you must then conduct three types of impacts are expected to conduct the following analyses when you make a BART determination:

Impact analysis part 1: costs of compliance, ( taking into account the remaining useful life of the facility)

Impact analysis part 2: energy impacts, and Impact analysis part 3: non air quality environmental impacts.

In this section, we describe how to conduct each of these three analyses. You are responsible for presenting an evaluation of each impact along with appropriate supporting information. You should discuss and, where possible, quantify both beneficial and adverse impacts. In general, the analysis should focus on the direct impact of the control alternative.

a. Impact analysis part 1: How do I estimate the costs of control?

1. To conduct a cost analysis, you:

( 1) identify the emissions units being controlled,

( 2) identify design parameters for emission controls, 66 and ( 3) develop cost estimates based upon those design parameters.

2. It is important to identify clearly the emission units being controlled, that is, to specify a well defined area or process segment within the plant. In some cases, multiple emission units can be controlled jointly. However, in other cases, it may be appropriate in the cost analysis to consider whether multiple units will be required to install separate and/ or different control devices. The analysis should provide a clear summary list of equipment and the associated control costs. Inadequate documentation of the equipment whose emissions are being controlled is a potential cause for confusion in comparison of costs of the same controls applied to similar sources.

3. You then specify the control system design parameters.

Potential sources of these design parameters include equipment vendors, background information documents used to support NSPS development, control technique guidelines documents, cost manuals developed by EPA, control data in trade publications, and engineering and performance test data. The following are a few examples of design parameters for two example control measures: 67 Control Device Examples of Design Parameters Wet Scrubbers Type of sorbent used ( lime,

limestone, etc.)

Gas pressure drop Liquid/ gas ratio Selective Catalytic Reduction Ammonia to NOx molar ratio Pressure drop Catalyst life 4. The value selected for the design parameter should ensure that the control option will achieve the level of emission control being evaluated. You should include in your analysis documentation of your assumptions regarding design parameters. Examples of supporting references would include the Office of Air Quality Planning and Standards ( OAQPS) Control Cost Manual ( see below) and background information documents used for NSPS and hazardous pollutant emission standards. If the design parameters you specified differ from typical designs, you should document the difference by supplying performance test data for the 10 The Control Cost Manual is updated periodically. While this citation refers to the latest version at the time this guidance was written, you should use the version that is current as of when you conduct your impact analysis. This document is available at the following Web site: http:// www. epa. gov/ ttn/ catc/ dir1/ chpt2acr. pdf 11 You should include documentation for any additional information you used for the cost calculations, including any information supplied by vendors that affects your assumptions regarding purchased equipment costs, equipment life, replacement of major components, and any other element of the calculation that differs from the Control Cost Manual.

68 control technology in question applied to the same source or a similar source.

5. Once the control technology alternatives and achievable emissions performance levels have been identified, you then develop estimates of capital and annual costs. The basis for equipment cost estimates also should be documented,

either with data supplied by an equipment vendor ( i. e.,

budget estimates or bids) or by a referenced source ( such as the OAQPS Control Cost Manual, Fifth Edition, February 1996,

EPA 453/ B 96 001). 10 In order to maintain and improve consistency, cost estimates should be based on the EPA/ OAQPS Control Cost Manual, where possible. 11 The Control Cost Manual addresses most control technologies in sufficient detail for a BART analysis. While the types of sitespecific analyses contained in the Control Cost Manual are less precise than those based upon a detailed engineering 69 design, normally the estimates provide results that are plus or minus 30 percent, which is generally sufficient for the BART review. The cost analysis should take into account site specific conditions that are out of the ordinary ( e. g.,

use of a more expensive fuel or additional waste disposal costs) that may affect the cost of a particular BART technology option.

b. How do I take into account a project's " remaining useful life" in calculating control costs?

1. You treat the requirement to consider the source's " remaining useful life" of the source for BART determinations as one element of the overall cost analysis.

The " remaining useful life" of a source, if it represents a relatively short time period, may affect the annualized costs of retrofit controls. For example, the methods for calculating annualized costs in EPA's Control Cost Manual require the use of a specified time period for amortization that varies based upon the type of control. If the remaining useful life will clearly exceed this time period,

the remaining useful life has essentially no effect on control costs and on the BART determination process. Where the remaining useful life is less than the time period for amortizing costs, you should use this shorter time period in your cost calculations. 70 2. For purposes of these guidelines, the remaining useful life is the difference between:

( 1) January 1 of the year the date that controls will be put in place ( capital and other construction costs incurred before controls are put in place would can be rolled into the first year, per as suggested in EPA's Control Cost Manual); you are conducting the BART analysis; and ( 2) the date the facility permanently stops operations.

Where this affects the BART determination, this date must be assured by a federally enforceable restriction preventing further operation. A projected closure date, without such a federally enforceable restriction,

is not sufficient.

3. We recognize that there may be situations where a source operator intends to shut down a source by a given date, but wishes to retain the flexibility to continue operating beyond that date in the event, for example, that market conditions change. Where this is the case, your BART analysis may account for this, but it must maintain consistency with the statutory requirement to install BART within 5 years. Where the source chooses not to accept a federally enforceable condition requiring the source to shut down by a given date, it is necessary to determine whether a reduced time period for the remaining useful 71 life changes the level of controls that would have been required as BART. If the reduced time period does change the level of BART controls, you may identify, and include as part of the BART emission limitation, the more stringent level of control that would be required as BART if there were no assumption that reduced the remaining useful life. You may incorporate into the BART emission limit this more stringent level, which would serve as a contingency should the source continue operating more than 5 years after the date EPA approves the relevant SIP. The source would not be allowed to operate after the 5 year mark without such controls. If a source does operate after the 5 year mark without BART in place, the source is considered to be in violation of the BART emissions limit for each day of operation.

c. What do we mean by cost effectiveness?

Cost effectiveness, in general, is a criterion used to assess the potential for achieving an objective in the most economical way. For purposes of air pollutant analysis,

" effectiveness" is measured in terms of tons of pollutant emissions removed, and " cost" is measured in terms of annualized control costs. We recommend two types of costeffectiveness calculations  average cost effectiveness,

and incremental cost effectiveness.

d. How do I calculate average cost effectiveness?

Average cost effectiveness means the total annualized 12 Whenever you calculate or report annual costs, you should indicate the year for which the costs are estimated. For example, if you use the year 2000 as the basis for cost comparisons, you would report that an annualized cost of $ 20 million would be: $ 20 million ( year 2000 dollars).

72 costs of control divided by annual emissions reductions ( the difference between baseline annual emissions and the estimate of emissions after controls), using the following formula:

Average cost effectiveness ( dollars per ton removed) =

Control option annualized cost12 Baseline annual emissions  Annual emissions with Control option Because you calculate costs in ( annualized) dollars per year ($/ yr) and because you calculate emissions rates in tons per year ( tons/ yr), the result is an average costeffectiveness number in ( annualized) dollars per ton ($/ ton)

of pollutant removed.

e. How do I calculate baseline emissions?

1. The baseline emissions rate should represent a realistic depiction of anticipated annual emissions for the source. In general, for the existing sources subject to BART, you will estimate the anticipated annual emissions based upon actual emissions from a baseline period.

2. When you project that future operating parameters ( e. g., limited hours of operation or capacity utilization, 73 type of fuel, raw materials or product mix or type) will differ from past practice, and if this projection has a deciding effect in the BART determination, then you must make these parameters or assumptions into enforceable limitations. In the absence of enforceable limitations, you calculate baseline emissions based upon continuation of past practice.

3. For example, the baseline emissions calculation for an emergency standby generator may consider the fact that the source owner would not operate more than past practice of 2 weeks a year. On the other hand, baseline emissions associated with a base loaded turbine should be based on its past practice which would indicate a large number of hours of operation. This produces a significantly higher level of baseline emissions than in the case of the emergency/ standby unit and results in more cost effective controls. As a consequence of the dissimilar baseline emissions, BART for the two cases could be very different.

f. How do I calculate incremental cost effectiveness?

1. In addition to the average cost effectiveness of a control option, you should also calculate incremental cost effectiveness. You should consider the incremental cost effectiveness in combination with the average cost effectiveness in order to justify consideration or elimination of a control 74 option. The incremental cost effectiveness calculation compares the costs and emissions performance level of a control option to those of the next most stringent option, as shown in the 75 following formula:

Incremental Cost Effectiveness ( dollars per incremental ton removed)

=

( Total annualized costs of control option)  ( Total annualized costs of next control option)

÷ ( Control option annual emissions)  ( Next control option annual emissions)

Example 1: Assume that Option F on Figure 2 has total annualized costs of $ 1 million to reduce 2000 tons of a pollutant, and that Option D on Figure 2 has total annualized costs of $ 500,000 to reduce 1000 tons of the same pollutant. The incremental cost effectiveness of Option F relative to Option D is ($ 1 million  $ 500,000) divided by ( 2000 tons

1000 tons), or $ 500,000 divided by 1000 tons,

which is $ 500/ ton.

Example 2: Assume that two control options exist: Option 1 and Option 2. Option 1 achieves a 1,000 ton/ yr reduction at an annualized cost of $ 1,900,000.

This represents an average cost of ($ 1,900,000 /

1,000 tons) = $ 1,900/ ton. Option 2 achieves a 980 tons/ yr reduction at an annualized cost of 76 $ 1,500,000. This represents an average cost of ($ 1,500,000 / 980 tons) = $ 1,531/ ton. The incremental cost effectiveness of Option 1 relative to Option 2 is ($ 1,900,000  $ 1,500,000)

divided by ( 1,000 tons  980 tons). The adoption of Option 1 instead of Option 2 results in an incremental emission reduction of 20 tons per year at an additional cost of $ 400,000 per year. The incremental cost of Option 1, then, is $ 20,000 per ton   11 times the average cost of $ 1,900 per ton.

While $ 1,900 per ton may still be deemed reasonable, it is useful to consider both the average and incremental cost in making an overall cost effectiveness finding. Of course, there may be other differences between these options, such as, energy or water use, or non air environmental effects, which also should be considered in selecting a BART technology.

2. You should exercise care in deriving incremental costs of candidate control options. Incremental costeffectiveness comparisons should focus on annualized cost and emission reduction differences between " dominant"

alternatives. To identify dominant alternatives, you generate a graphical plot of total annualized costs for 77 total emissions reductions for all control alternatives identified in the BART analysis, and by identifying a " least cost envelope" as shown in Figure 2. ( A " least cost envelope" represents the set of options that should be dominant in the choice of a specific option.)

Example: Eight technically feasible control options for analysis are listed in the BART ranking. These are represented as A through H in Figure 2. The dominant set of control options, B, D, F, G, and H, represent the least cost envelope, as we depict by the cost curve 78 connecting them. Points A, C and E are inferior options, and you should not use them in calculating incremental cost effectiveness. Points A, C and E represent inferior controls because B will buy more emissions reductions for less money than A; and similarly, D and F will buy more reductions for less money than C and E, respectively.

3. In calculating incremental costs, you:

( 1) RankArray the control options in ascending order of annualized total costs,

( 2) Develop a graph of the most reasonable smooth curve of the control options, as shown in Figure 2. This is to show the " least cost envelope"

discussed above; and ( 3) Calculate the incremental cost effectiveness for each dominant option, which is the difference in total annual costs between that option and the next most stringent option, divided by the difference in emissions, after controls have been applied, between those two control options. For example, using Figure 2, you would calculate incremental cost effectiveness for the difference between options B and D, options D and F, options F and G, and options G and H. 79 4. A comparison of incremental costs can also be useful in evaluating the viability of a specific control option over a range of efficiencies. For example, depending on the capital and operational cost of a control device, total and incremental cost may vary significantly ( either increasing or decreasing) over the operational range of a control device. Also, the greater the number of possible control options that exist, the more weight should be given to the incremental costs vs. average costs. It should be noted that average and incremental cost effectiveness are identical when only one candidate control option is known to exist.

5. You should exercise caution not to misuse these techniques. For example, you may be faced with a choice between two available control devices at a source, control A and control B, where control B achieves slightly greater emission reductions. The average cost ( total annual cost/ total annual emission reductions) for each may be deemed to be reasonable. However, the incremental cost ( total annual costA B / total annual emission reductionsA B) of the additional emission reductions to be achieved by control B may be very great. In such an instance, it may be inappropriate to choose control B, based on its high incremental costs, even though its average cost may be 80 considered reasonable.

6. In addition, when you evaluate the average or incremental cost effectiveness of a control alternative, you should make reasonable and supportable assumptions regarding control efficiencies. An unrealistically low assessment of the emission reduction potential of a certain technology could result in inflated cost effectiveness figures.

g. What other information should I provide in the cost impacts analysis?

You should provide documentation of any unusual circumstances that exist for the source that would lead to cost effectiveness estimates that would exceed that for recent retrofits. This is especially important in cases where recent retrofits have cost effectiveness values that are within what has been considered a reasonable range, but your analysis concludes that costs for the source being analyzed are not considered reasonable. ( A reasonable range would be a range that is consistent with the range of cost effectiveness values used in other similar permit decisions over a period of time.)

Example: In an arid region, large amounts of water are needed for a scrubbing system. Acquiring water from a distant location could greatly increase the cost effectiveness of wet scrubbing as a control 81 option.

h. What other things are important to consider in the cost impacts analysis?

In the cost analysis, you should take care to not focus on incomplete results or partial calculations. For example,

large capital costs for a control option alone would not preclude selection of a control measure if large emissions reductions are projected. In such a case, low or reasonable cost effectiveness numbers may validate the option as an appropriate BART alternative irrespective of the large capital costs. Similarly, projects with relatively low capital costs may not be cost effective if there are few emissions reduced.

h. Impact analysis part 2: How should I analyze and report energy impacts?

1. You should examine the energy requirements of the control technology and determine whether the use of that technology results in any significant or unusual energy penalties or benefits. A source owner may, for example,

benefit from the combustion of a concentrated gas stream rich in volatile organic compounds; on the other hand, more often extra fuel or electricity is required to power a control device or incinerate a dilute gas stream. If such benefits or penalties exist, they should be quantified and 82 included in the cost analysis. Because energy penalties or benefits can usually be quantified in terms of additional cost or income to the source, the energy impacts analysis can, in most cases, simply be factored into the cost impacts analysis. However, certain types of control technologies have inherent energy penalties associated with their use.

While you should quantify these penalties, so long as they are within the normal range for the technology in question,

you should not consider such penalties to be an adequate justification for eliminating that technology from consideration.

2. Your energy impact analysis should consider only direct energy consumption and not indirect energy impacts. For example, you could estimate the direct energy impacts of the control alternative in units of energy consumption at the source ( e. g., BTU, kWh, barrels of oil, tons of coal). The energy requirements of the control options should be shown in terms of total ( and in certain cases, also incremental)

energy costs per ton of pollutant removed. You can then convert these units into dollar costs and, where appropriate, factor these costs into the control cost analysis.

3. You generally do not consider indirect energy impacts ( such as energy to produce raw materials for construction of 83 control equipment). However, if you determine, either independently or based on a showing by the source owner,

that the indirect energy impact is unusual or significant and that the impact can be well quantified, you may consider the indirect impact.

4. The energy impact analysis may also address concerns over the use of locally scarce fuels. The designation of a scarce fuel may vary from region to region. However, in general, a scarce fuel is one which is in short supply locally and can be better used for alternative purposes, or one which may not be reasonably available to the source either at the present time or in the near future.

5. Finally, the energy impacts analysis may consider whether there are relative differences between alternatives regarding the use of locally or regionally available coal,

and whether a given alternative would result in significant economic disruption or unemployment. For example, where two options are equally cost effective and achieve equivalent or similar emissions reductions, one option may be preferred if the other alternative results in significant disruption or unemployment.

i. Impact analysis part 3: How do I analyze " non air quality environmental impacts?"

1. In the non air quality related environmental impacts 84 portion of the BART analysis, you address environmental impacts other than air quality due to emissions of the pollutant in question. Such environmental impacts include solid or hazardous waste generation and discharges of polluted water from a control device.

2. You should identify any significant or unusual environmental impacts associated with a control alternative that have the potential to affect the selection or elimination of a control alternative. Some control technologies may have potentially significant secondary environmental impacts. Scrubber effluent, for example, may affect water quality and land use. Alternatively, water availability may affect the feasibility and costs of wet scrubbers. Other examples of secondary environmental impacts could include hazardous waste discharges, such as spent catalysts or contaminated carbon. Generally, these types of environmental concerns become important when sensitive site specific receptors exist or when the incremental emissions reductions potential of the more stringent control is only marginally greater than the next most effective option. However, the fact that a control device creates liquid and solid waste that must be disposed of does not necessarily argue against selection of that technology as BART, particularly if the control device has 85 been applied to similar facilities elsewhere and the solid or liquid waste is similar to those other applications. On the other hand, where you or the source owner can show that unusual circumstances at the proposed facility create greater problems than experienced elsewhere, this may provide a basis for the elimination of that control alternative as BART.

3. The procedure for conducting an analysis of non air quality environmental impacts should be made based on a consideration of site specific circumstances. If you propose to adopt the most stringent alternative, then it is not necessary to perform this analysis of environmental impacts for the entire list of technologies you ranked in Step 3. In general, the analysis need only address those control alternatives with any significant or unusual environmental impacts that have the potential to affect the selection of a control alternative, or elimination of a more stringent control alternative. Thus, any important relative environmental impacts ( both positive and negative) of alternatives can be compared with each other.

4. In general, the analysis of impacts starts with the identification and quantification of the solid, liquid, and gaseous discharges from the control device or devices under review. Initially, you should perform a qualitative or 86 semi quantitative screening to narrow the analysis to discharges with potential for causing adverse environmental effects. Next, you should assess the mass and composition of any such discharges and quantify them to the extent possible, based on readily available information. You should also assemble pertinent information about the public or environmental consequences of releasing these materials.

j. What are examples of non air quality environmental impacts?

The following are examples of how to conduct non air quality environmental impacts:

( 1) Water Impact You should identify the relative quantities of water used and water pollutants produced and discharged as a result of the use of each alternative emission control system relative to the most stringent alternative. Where possible, you should assess the effect on ground water and such local surface water quality parameters as ph, turbidity, dissolved oxygen,

salinity, toxic chemical levels, temperature, and any other important considerations. The analysis should consider whether applicable water quality standards will be met and the availability and effectiveness of various techniques to reduce potential adverse effects. 87 ( 2) Solid Waste Disposal Impact You should compare the quality and quantity of solid waste ( e. g., sludges, solids) that must be stored and disposed of or recycled as a result of the application of each alternative emission control system with the quality and quantity of wastes created with the most stringent emission control system. You should consider the composition and various other characteristics of the solid waste ( such as permeability, water retention, rewatering of dried material, compression strength, leachability of dissolved ions, bulk density, ability to support vegetation growth and hazardous characteristics) which are significant with regard to potential surface water pollution or transport into and contamination of subsurface waters or aquifers.

( 3) Irreversible or Irretrievable Commitment of Resources You may consider the extent to which the alternative emission control systems may involve a trade off between short term environmental gains at the expense of long term environmental losses and the extent to which the alternative systems may result in irreversible or irretrievable commitment of resources 88 ( for example, use of scarce water resources).

( 4) Other Adverse Environmental Impacts You may consider significant differences in noise levels, radiant heat, or dissipated static electrical energy. Other examples of non air quality environmental impacts would include hazardous waste discharges such as spent catalysts or contaminated carbon. Generally, these types of environmental concerns become important when the plant is located in an area that is particularly sensitive to environmental degradation and when the incremental emissions reductions potential of the most stringent control option is only marginally greater than the next mosteffective option, but the environmental impact is of greater concern.

( 5) Benefits to the Environment It is important to consider relative differences between options regarding their beneficial impacts to non air quality related environmental media. For example, you may consider whether a given control option results in less deposition of pollutants, in particular nitrogen compounds, to nearby sensitive water bodies. You may also consider effects which may be unique to high elevation ecosystems. In some 89 eastern Class I areas with elevations above 1000 meters, there may be direct deposition of acid and nitrogen compounds on vegetation and soil from cloud impacts. Growth rates and competition between alien and native species might be affected by pollution loadings as well. As part of the consultation requirement between States and the Federal Land Managers in 40 CFR 51.308( i)( 2), we expect the Federal Land Managers to provide information on non air quality indicators to be considered in determining BART and other implementation strategies. The States should also consider such information available from other sources, such as public comments.

5. Step 5: How should I determine visibility impacts in the BART determination?

The following is the approach to determine visibility impacts ( the degree of visibility improvement for each source subject to BART) for the BART determination. Once you have determined that your source or sources are subject to BART, you must conduct a visibility improvement determination for the source( s) as part of the BART determination. When making this determination, we believe you should have flexibility in setting absolute thresholds, target levels of improvement, or de minimis levels since the deciview improvement must be weighed among the 13 The model code and its documentation are available at no cost for download from the model developers' Internet Web site: http:// www. src. com/ calpuff/ calpuff1. htm.

90 five factors, and you are free to determine the weight and significance to be assigned to each factor. For example, a 0.3 deciview improvement may merit a stronger weighting in one case versus another, so one " bright line" may not be appropriate.

[ Note that if sources have elected to apply the most stringent controls available, consistent with the discussion in section E.

step 1. below, you need not conduct, or require the source to conduct, an air quality modeling analysis for the purpose of determining its visibility impacts].

Use the CALPUFF13, or other EPA approved model to determine the visibility improvement expected at a Class I area from the potential BART control technology applied to the source.

Modeling should be conducted for SO2, NOx, and direct PM emissions ( PM2.5 and PM10). If the source is making the visibility determination, you should review and approve or disapprove of the source's analysis before making the expected improvement determination. For the Source analysis:

! Submit a modeling protocol to EPA If you are allowing the source to do the modeling, it must prepare a modeling protocol that is acceptable to you and EPA. Some critical items to include are meteorological and terrain data, as well as source 14 Interagency Workgroup on Air Quality Modelig ( IWAQM) Phase 2 Summary Report and Recommendations for Modeling Long Range Transport Impacts, U. S. Environmental Protection Agency, EPA 454/ R 98 019, December 1998.

91 specific information ( stack height, temperature, exit velocity, elevation, and allowable and actual emission rates of applicable pollutants), and receptor data from appropriate Class I areas. We recommend following EPA's Interagency Workgroup on Air Quality Modeling ( IWAQM) Phase 2 Summary Report and Recommendations for Modeling Long Range Transport Impacts14 for parameter settings and meteorological data inputs; the use of other settings from those in IWAQM must be identified and explained in the protocol. All receptors in the nearest Class I area should be analyzed. For other Class I areas in relatively close proximity to a BARTeligible source, a State may model a few strategic receptors at those other Class I areas ( perhaps at the closest point to the source, a receptor at the highest and lowest elevation in the Class I area, a receptor at the IMPROVE monitor, and a few receptors that are expected to be at the approximate plume release height). If the highest modeled impacts are observed at the nearest Class I area, a State may choose not to analyze the other Class I areas any further and 92 additional analyses might be unwarranted. Otherwise, a full field of receptors should be modeled for the Class I area with the highest impact. The State should bear in mind that, some receptors within that Class I area may be less than 50 km from the source while other receptors within that same Class I area may be greater than 50 km from the same source; this situation may result in two different modeling approaches for the same Class I area and source, depending upon the State's chosen method for modeling sources less than 50 km. In situations where the State is assessing visibility impacts for source receptor distances less than 50 km, States should use discretion in determining visibility impacts, giving consideration to both CALPUFF and other EPA approved methods.

! Once the modeling protocol is approved, for each source, run CALPUFF, or other EPA approved model, at pre control and post control emission rates according to the accepted methodology in the protocol.

Calculate 24 hr values, using the actual 24 hour emission rate, from the worst day of the meteorological period modeled ( for the pre control scenario), for each receptor as the change in deciviews compared against natural visibility 93 conditions( the natural visibility background average of the 20% best days). Post control emission rates are pre control emission rates x ( 1  the percent control efficiency of the scenario being evaluated).

! Make the net visibility improvement determination Assess the visibility improvement based on the modeled change in visibility impact for the precontrol and post control emission scenarios. You have flexibility to assess visibility improvements due to BART controls by one or more methods. It is important to make the determination by considering the frequency, magnitude, and duration components of impairment. When making the visibility improvement determination, both " average" and " peak" tests are crucial in making the assessment.

Suggestions for making the determination are:

° use of a comparison threshold, as is done for determining if BART eligible sources should be subject to a BART determination. Comparison thresholds can be used in a number of ways in evaluating visibility improvement ( e. g. 94 the number of days or hours that the threshold was exceeded, a single threshold for determining whether a change in impacts is significant, a threshold representing an x percent change in improvement, etc.).

° Examine distributions of the hourly or daily impacts, compare the hourly values to thresholds, determine if the time of year is important ( e. g. high impacts are occurring during tourist season).

° Compare the worst case days for the preand post control runs.

° Use combinations of the above to assess expected improvement.

Note that each of the modeling options may be supplemented with source apportionment data or source apportionment modeling that is acceptable to the State and the EPA regional office.

E. How do I select the " best" alternative, using the results of Steps 1 through 5?

1. Summary of the Impacts Analysis From the alternatives you rankedevaluated in Step 3, we recommend you should develop a chart ( or charts) displaying for each of the ranked alternatives: 95 ( 1) expected emission rate ( tons per year, pounds per hour);

( 2) emissions performance level ( e. g., percent pollutant removed, emissions per unit product,

lb/ MMbtu, ppm);

( 3) expected emissions reductions ( tons per year);

( 4) costs of compliance  total annualized costs ($),

cost effectiveness ($/ ton), and incremental cost effectiveness ($/ ton);

( 5) energy impacts ( indicate any significant energy benefits or disadvantages);

( 6) non air quality environmental impacts ( includes any significant or unusual other media impacts,

e. g., water or solid waste), both positive and negative; and ( 7) modeled visibility impacts.

2. Selecting a " best" alternative 1. You have discretion to determine the order in which you should evaluate control options for BART. You should evaluate several different options, if available, including a complete evaluation of the most stringent option or options. You should select the most stringent alternative in the ranking that does not impose unreasonable costs of compliance, taking into account both average and incremental 96 costs, and considering visibility effects and any energy and non air quality environmental impacts.

2. If you select an alternative that is not the most stringent alternative, then you need to document the rationale for this finding for the public record, noting which of the CAA factors ( cost of compliance, visibility impacts, energy and/ or non air quality environmental impacts) rendered this choice unacceptable.

3. Whatever the order in which you choose to evaluate options, you should always ( 1) display and rank all of the options in order of control effectiveness and to the options evaluated; ( 2) identify the average and incremental costs of each option; ( 3) consider the energy and non air quality environmental impacts of each option; and ( 4) consider the remaining useful life; and ( 5) consider the modeled visibility impacts. You should provide a justification for adopting the technology that you select as the " best" level of control, including an explanation of the CAA factors that led you to reject any other more stringent control levels.

2. In the case where you are conducting a BART determination for two regulated pollutants on the same source, if the result is two different BART technologies that do not work well together, you could then substitute a different technology or combination of technologies, 97 provided that they achieve at least the same emissions reductions for each pollutant.

3. In selecting a " best" alternative, should I consider the affordability of controls?

1. Even if the control technology is cost effective, there may be cases where the installation of controls would affect the viability of continued plant operations.

2. As a general matter, for plants with significant visibility impacts that are essentially uncontrolled at present, and emit at much greater levels per unit of production than other plants in the category, we are unlikely to accept as BART any analysis that preserves a source's uncontrolled status on the basis that the installation of controls would result in a shutdown of the facility. While this result could appear to impose a hardship on such facilities, we believe that the flexibility provided in the regional haze rule for an alternative reduction approach, such as an emissions trading program,

will minimize the likelihood of forced shutdowns.

2. Nonetheless, we recognize tThere may be unusual circumstances that justify taking into consideration the conditions of the plant and the economic effects of requiring the use of a given control technology. These effects would include effects on product prices, the market 98 share, and profitability of the source. We do not intend,

for example, that the most stringent alternative must always be selected, if that level would cause a plant to shut down,

while a slightly lesser degree of control would not have this effect. Where there are such unusual circumstances that are judged to have a severe effect on plant operations,

you may take into consideration the conditions of the plant and the economic effects of requiring the use of a control technology. Where these effects are judged to have a severe impact on plant operations you may consider them in the selection process, so long as you provide an economic analysis that demonstrates, in sufficient detail for a meaningful public review, the specific economic effects,

parameters, and reasoning. ( We recognize that this review process must preserve the confidentiality of sensitive business information). Any analysis should consider whether other competing plants in the same industry may also be required to install BART controls.

4. Sulfur dioxide limits for utility boilers You must require 750 MW power plants to meet specific control levels for SO2 of either 95 percent control or .15 lbs/ MMBtu, for each EGU greater than 200 MW that is currently uncontrolled, unless you determine that an alternative control level is clearly justified based on a 99 careful consideration of the statutory factors. Thus, for example, if the source convincingly demonstrates unique circumstances affecting its ability to cost effectively reduce its emissions, you should take that into account in determining whether the presumptive levels of control are appropriate for that facility. For a currently uncontrolled EGU greater than 200 MW in size, but located at a power plant smaller than 750 MW in size, such controls are generally cost effective and should be carefully considered in your BART analysis. While these levels may represent current control capabilities, we expect that scrubber technology will continue to improve and control costs continue to decline. You should be sure to consider the level of control that is currently best achievable at the time that you are conducting your BART analysis.

For coal fired EGUs with existing post combustion SO2 controls achieving less than 50 percent removal efficiencies, we recommend that you evaluate constructing a new FGD system to meet the same emission limits as above ( 95 percent removal or 0.15 lb/ mmBtu), in addition to the evaluation of scrubber upgrades discussed below. For oilfired units, regardless of size, you should evaluate limiting the sulfur content of the fuel oil burned to be 1 percent or less by weight. 100 For those BART eligible EGUs with pre existing postcombustion SO2 controls achieving removal efficiencies of at least 50 percent, your emission limit should be the result,

in part, of an evaluation of cost effective scrubber upgrades designed to improve the system's overall SO2 removal efficiency. There are numerous scrubber enhancements available to upgrade the average removal efficiencies of all types of existing scrubber systems. We recommend that as you evaluate the definition of " upgrade," you evaluate options that not only improve the design removal efficiency of the scrubber vessel itself, but also consider upgrades that can improve the overall SO2 removal efficiency of the scrubber system. Increasing a scrubber system's reliability, and conversely decreasing its downtime, by way of optimizing operation procedures, improving maintenance practices, adjusting scrubber chemistry, and increasing auxiliary equipment redundancy, are all ways to improve average SO2 removal efficiencies.

We recommend that as you evaluate the performance of existing wet scrubber systems, you consider some of the following upgrades, in no particular order, as potential scrubber upgrades that have been proven in the industry as cost effective means to increase overall SO2 removal of wet systems: 101 ( a) Elimination of Bypass Reheat;

( b) Installation of Liquid Distribution Rings;

( c) Installation of Perforated Trays;

( d) Use of Organic Acid Additives;

( e) Improve or Upgrade Scrubber Auxiliary System Equipment;

( f) Redesign Spray Header or Nozzle Configuration.

We recommend that as you evaluate upgrade options for dry scrubber systems, you should consider the following cost effective upgrades, in no particular order:

( a) Use of Performance Additives;

( b) Use of more Reactive Sorbent;

( c) Increase the Pulverization Level of Sorbent;

( d) Engineering redesign of atomizer or slurry injection system.

You should evaluate scrubber upgrade options based on the 5 step BART analysis process.

5. Nitrogen oxide limits for utility boilers You should establish specific numerical limits for NOx control for each BART determination. For power plants with a generating capacity in excess of 750 MW currently using selective catalytic reduction ( SCR) or selective non catalytic reduction ( SNCR) for part of the year, you should presume that use of those same controls year round is BART. For other sources currently using SCR or SNCR to reduce NOx emissions during part of the year, 15 No Cell burners, dry turbo fired units, nor wet bottom tangential fired units burning lignite were identified as BART eligible, thus no presumptive limit was determined. Similarly, no wet bottom tangential fired units burning subbituminous were identified as BART eligible.

102 you should carefully consider requiring the use of these controls year round as the additional costs of operating the equipment throughout the year would be relatively modest.

For coal fired EGUs greater than 200 MW located at greater than 750 MW power plants and operating without postcombustion controls ( i. e. SCR or SNCR), we have providedestablished NOx limits that you should establish,

differentiated by boiler design and type of coal burned,

unless you determine that an alternative control level is appropriate based on a careful consideration of the statutory factors. For coal fired EGUs greater than 200 MW located at power plants 750 MW or less in size and operating without post combustion controls, you should likewise presume that these same levels are cost effective. You must require such utility boilers to meet the following NOx emission limits, unless you determine that an alternative control level is clearly justified based on a careful consideration of the statutory factors:

Table 1: Presumptive NOx emission limits for BART eligible coalfired units. 15 16 These limits reflect the design and technological assumptions discussed in the technical support document for NOx limits for these guidelines. See Technical Support Document for BART NOx Limits for Electric Generating Units and Technical Support Document for BART NOx Limits for Electric Generating Units Excel Spreadsheet, Memorandum to Docket OAR 2002 0076, April 15, 2005.

103 Unit type Coal type NOx presumptive limit ( lb/ mmbtu) 16 Dry bottom wallfired Bituminous 0.39 Sub bituminous 0.23 Lignite 0.29 Tangential fired Bituminous 0.28 Sub bituminous 0.15 Lignite 0.17 Cell Burners Bituminous 0.40 Sub bituminous 0.45 Dry turbo fired Bituminous 0.32 Sub bituminous 0.23 Wet bottom tangential fired Bituminous 0.62 Most EGUs can meet these presumptive NOx limits through the use of current combustion control technology, i. e. the careful control of combustion air and low NOx burners. For units that cannot meet these limits using such technologies,

you should consider whether advanced combustion control technologies such as rotating opposed fire air should be used to meet these limits.

Because of the relatively high NOx emission rates of 17 See Technical Support Document for BART NOx Limits for Electric Generating Units and Technical Support Document for BART NOx Limits for Electric Generating Units Excel Spreadsheet, Memorandum to Docket OAR 2002 0076, April 15, 2005.

104 cyclone units, SCR is more cost effective than the use of current combustion control technology for these units. The use of SCRs at cyclone units burning bituminous coal,

subbituminous coal, and lignite should enable the units to cost effectively meet NOx rates of 0.10 lbs/ mmbtu. As a result, we are establishing a presumptive NOx limit of O. 10 lbs/ mmbtu based on the use of SCR for coal fired cyclone units greater than 200 MW located at 750 MW power plants.

As with the other presumptive limits established in this guideline, you may determine that an alternative level of control is appropriate based on your consideration of the relevant statutory factors. For other cyclone units, you should review the use of SCR and carefully consider whether these post combustion controls should be required as BART.

For oil fired and gas fired EGUs, we recommend that you carefully consider requiring these units to install current combustion control technology to control NOx. Many such units can make significant reductions in NOx emissions which are highly cost effective through the application of current combustion control technology. 17 105 V. ENFORCEABLE LIMITS/ COMPLIANCE DATE To complete the BART process, you must establish enforceable emission limits and require compliance within a given period of time. In particular, you must establish an enforceable emission limit for each subject emission unit at the source and for each pollutant subject to review that is emitted from the source. In addition, you must require compliance with the BART emission limitations no later than 5 years after EPA approves your regional haze SIP. If technological or economic limitations in the application of a measurement methodology to a particular emission unit would make an emissions limit infeasible, you may prescribe a design, equipment, work practice, operation standard,

or combination of these types of standards. You should ensure that any BART requirements are written in a way that clearly specifies the individual emission unit( s) subject to BART review.

Because the BART requirements are " applicable" requirements of the CAA, they must be included as title V permit conditions according to the procedures established in 40 CFR part 70 or 40 CFR part 71.

Section 302( k) of the CAA requires emissions limits such as BART to be met on a continuous basis. Although this provision does not necessarily require the use of continuous emissions monitoring ( CEMs), it is important that sources employ techniques that ensure compliance on a continuous basis. Monitoring 106 requirements generally applicable to sources, including those that are subject to BART, are governed by other regulations.

See, e. g., 40 CFR part 64 ( compliance assurance monitoring); 40 CFR 70.6( a)( 3) ( periodic monitoring); 40 CFR 70.6( c)( 1)

( sufficiency monitoring). Note also that while we do not believe that CEMs would necessarily be required for all BART sources, the vast majority of electric generating units potentially subject to BART already employ CEM technology for other programs, such as the acid rain program. In addition, emissions limits must be enforceable as a practical matter ( contain appropriate averaging times, compliance verification procedures and recordkeeping requirements). In light of the above, the permit must: