Recommendations for Improved Implementation of the Regional Haze 

Program

USDA Forest Service

May 2014

The Federal Land Managers (FLMs) are responsible for protecting resources in mandatory

Class I federal areas; however, the FLMs do not have regulatory authority under the Regional

Haze Rule to control air emissions that impair visibility. As partners in achieving the Clean Air

Act goals, we emphasize the importance of EPA-FLM collaboration, in addition to regulatory 

consultation. We encourage earlier and better communication as we move forward into the next 

regional haze planning cycle.

USDA FS recommendations for improving the Regional Haze Program are explained below.

I. Focus on Controllable Anthropogenic Emissions Sources

Under the Clean Air Act, States have jurisdiction over specific categories of emissions sources.

The Regional Haze Rule directs States to implement reasonable controls to reduce man-made 

impairment towards achieving the national visibility goal. However, there exist anthropogenic 

sources of air pollution outside of a State’s ability to regulate, such as emissions originating in 

other countries. Situations also exist where episodic natural emissions, such as volcanic 

eruptions, dust storms, or wildfires, greatly overshadow the man-made sources within the 

regulatory agencies’ control. Control of prescribed fire should consider climate change 

vulnerability and potential effects on wildfire potential.

Current EPA Guidance for Tracking Progress1 does not distinguish visibility impacts attributable 

to sources within State/Tribal jurisdiction from those caused by emission sources outside the 

agencies’ control. When outside anthropogenic or episodic natural emissions dominate selection 

of 20th percentile worst days, the benefits to visibility from anthropogenic emission reductions 

implemented by States are more difficult to demonstrate. The same happens when episodic 

natural emissions are not fully reflected in the estimate of natural conditions. The effective result 

is that, notwithstanding substantial reductions in emissions, a State’s regional haze progress 

demonstration may fail to show an equivalent improvement in visibility.

EPA guidance to focus on controllable anthropogenic emissions will allow States’ efforts in the 

next planning cycle to be more efficiently directed to evaluating and implementing emissions 

control strategies. We also recommend that each State first conduct a visibility source 

contribution assessment. This is essential to defining the pollutants and source categories to 

address.

 1 See EPA Guidance for Setting Reasonable Progress Goals Under the Regional Haze Program June 1, 2007.
Recommendations:

• In addition to the regulatory glidepath, allow States and Tribes the option to define a

glidepath from current visibility conditions to no man-made visibility impairment that

accounts for impairment due to episodic natural events and due to anthropogenic sources

outside the agencies’ regulatory control.

• Modeling methods can be used in addition to monitoring data to focus the visibility

demonstration on the days with the highest impairment attributed to controllable

anthropogenic emissions.

• When considering contribution of wildland prescribed fire and any potential control 

measures, Executive Order issued on November 1, 2013, guides that federal policies that 

can increase vulnerability of natural systems and natural resources to climate change 

related risks be reformed. EPA discussion of controllable emissions should consider this 

Executive Order and the Preamble discussion to the Regional Haze Rule. 
II. Provide Alternative “Default” Approach to Meet Reasonable Progress 

Goals

40 CFR §51.308(d)(1) requires States/Tribes to establish goals that provide for reasonable 

progress towards achieving natural visibility conditions. In the first regional haze planning cycle, 

States, Tribes, EPA, FLMs, and other stakeholders promoted diverse definitions of “reasonable” 

visibility goals. This caused resource intensive planning, ongoing debate over control decisions, 

and long-delayed SIP submittals.

We concur with DOI’s suggestion that EPA define an alternative approach which includes Statespecific emissions targets, supported by sufficient data for States to complete a four-factor 

analysis. The EPA-default approach would be set at levels sufficient to achieve reasonable 

progress for the controllable anthropogenic emissions within a State’s jurisdiction. Targets would 

give States/Tribes adequate flexibility to exercise self-governance, yet, if achieved, would result 

in “reasonable” progress for regional haze purposes. If a State implements its EPA default, then 

the expectations for success will be more certain, and plan development, review and approval 

will be streamlined. States not opting for the EPA default alternative would retain the existing 

§51.308(d)(1) process, which evaluates control measures for all source categories to define 

reasonable progress goals. If States opt not to use the default alternative, the considerations 

discussed in Section III become increasingly important. 

We have explored candidate methods for creating emissions based targets. Targets could be in 

the form of State-wide emission reduction or through visibility improvements that are specific to 

the Class I areas in each State (e.g., a linear reduction from the current condition to the 2064 

goal). We are interested in working with EPA to develop this concept.

Recommendations:

• Develop EPA-default alternative approaches for States/Tribes to meet reasonable

progress requirements.

• Where possible, develop presumptive control levels for specific source categories.

• Where possible, develop control technology guidelines for specific source categories that 

states could use for candidate technologies for various source categories.

• Involve FLM agencies, and potentially other stakeholders, in evaluating candidate 

methods.

• States should be given the opportunity to define prescribed fire emissions as part of 

natural background per the RHR Preamble which stated “...EPA believes States should 

be permitted to consider some amount of fire in the calculation [of natural background] to 

reflect the fact that some prescribed fire effects serve merely to offset what would be 

expected to occur naturally (64 FR 37535-35736). This prescribed fire level and any 

proposed controls should consider climate change related risks and potential contribution 

to wildfire risk and severity. 
III. Clarify Methods to Evaluate Reasonable Control Measures

40 CFR §51.308(d)(1)(i) instructs States to consider the four factors - costs of compliance, the

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

compliance and the remaining useful life of any potentially affected sources - and to include a 

demonstration of how these factors were taken into consideration in selecting the reasonable 

progress (RP) goal.

A “subject-to” process similar to BART has been suggested as a potential method to determine if 

an individual source or small group of sources should be considered for controls under 

reasonable progress. In our interpretation, the “subject-to” process of BART was mandated by 

the American Corn Growers’ court decision which allows for States to determine which 

source(s) “may reasonably be anticipated to cause or contribute to any impairment of visibility in 

any mandatory Class I Federal area” to be consistent with the BART requirements in Section 

169A(b)(2)(A) of the Clean Air Act. The concept of a “subject-to” analysis for RP under this 

context implies a “cause or contribute” test for visibility impairment for individual or small 

groups of sources, which is not directly supported under 169A(b)(2)(B) and could create 

inconsistencies with the intent of the long-term strategy component of the Regional Haze Rule

by placing emphasis on a single source RP review rather than approaches which look at the 

collective benefit across many sources.

2

Our concern lies in applying recommendations embodied within Appendix Y or the Federal 

Land Managers Air Quality Related Values Work Group (FLAG) Phase I Guidance without 

consideration to the methods/tools and thresholds recommended and how it would be employed 

within the RP context. We believe that recommending what is essentially a “cause or contribute” 

test will encourage States or EPA to exempt individual major and minor sources with smaller 

individual impacts, but if considered collectively in the same manner as mobile and area 

sources,3 would have significantly greater visibility impacts, and thus potential for greater 

visibility benefit from emissions controls.4 EPA has already approved the use of the Q/D 

approach for RP “screening” and as a pseudo-benefit metric for several SIPs and FIPs using 

thresholds recommended in FLAG 2010.

5

This overemphasis of a single source approach unnecessarily risks impeding the attainment of 

RP goals by artificially restricting the pool of stationary sources to be considered for emissions 

controls under the long-term strategy. Rather, it should be implemented in a manner which 

reflects the need for cumulative emissions controls. First, we assume that the BART process of 

the first planning cycle will have addressed many of the older sources with uncontrolled 

emissions, and that many sources constructed after 1977 were subject to New Source 

Performance Standards (NSPS) or Best Available Control Technology (BACT) emission limits. 

 2 See 64 FR 35735. “The State should review all such sources in identifying the emission reduction measures to be included in 

the strategy.”

3 See 64 FR 35735. “Depending on the nature of the visibility problem, road dust and other area sources may at times make a 

significant contribution to visibility impairment. States should include area sources in emission inventories and control strategy 

analyses as warranted.” 4 See 64 FR 35735. “The EPA believes that States should take the cumulative emissions from minor sources into account in 

developing their regional haze long-term strategies.” 5 See 77 FR 24609, 78 FR 34763.
As a result, many of the post-1977 sources, whether major or minor sources, have emissions 

levels which represent more efficient processes and better control technology and generally 

would have smaller corresponding visibility impacts as compared to BART sources. 

Individually, it is reasonable to conjecture that many of these sources would have corresponding 

Q/D ratios or modeled impacts that would fall below the respective “significance” thresholds 

outlined in FLAG 2010 or Appendix Y. Thus, at a minimum, any threshold recommended as 

part of a “subject-to” RP process would need to be adjusted to reflect a smaller threshold 

recognizing the need to evaluate cumulative emissions controls for the long term strategy 

requirements of the RHR.

The lack of specificity in the BART guidelines in modeling led to the use multiple of versions of 

the CALPUFF modeling system. Prior to June 2007, at least four different versions of the 

CALPUFF modeling system were employed (5.711a, 5.756, 6.112, and 6.221). Subsequent EPA 

technical review of the underlying model code found errors which had the potential to 

significantly affect model results in the latter three versions.6,7 In 2010, a new version 

introduced substantive modifications to the CALPUFF chemical mechanism (versions 6.34 and 

6.42) which fundamentally altered the model predictions and virtually eliminated source impacts 

compared to the EPA approved version (5.8). The updated model was used by large EGUs in 

BART determinations in Colorado, New Mexico, Arizona, and Nevada. EPA found itself having 

to defend use of different versions.8 The same practice will ultimately develop if EPA develops 

any modeling based guidance surrounding future RP determinations. We recommend that any 

such future guidance provide greater specificity to avoid similar issues.

Visibility benefit has also been suggested as a factor available to States to better understand the 

effect and has been employed by EPA in a number of RP evaluations, absent any clear statutory 

mandate to do so.9 We are concerned that the use of benefit as a fifth factor in RP 

determinations places undue emphasis on a single source approach to RP determinations rather 

than focusing upon cumulative emissions as has been suggested in the Regional Haze Rule. We 

recommend that future guidance for RP determinations be confined to the four statutory factors 

outlined in the Clean Air Act and 40 CFR §51.308(d)(1)(i).

EPA RP guidance suggested use of the dollar per deciview metric which merges estimates of 

costs and degree of visibility improvement as a potential metric for the first statutory factor –

 6 See EPA Assessment of the “VISTAS” Version of the CALPUFF Modeling System, EPA-454/R-08-007, August 2008. 7 See FR 76 52431. “Based on our review of the available evidence we do not consider the models to have been shown to be 

sufficiently documented, technically valid, and reliable for use in a BART decision making process. In addition, the available 

evidence would not support approval of these models for current regulatory use. There are known technical problems with 

CALPUFF 6.112 and furthermore, the development of new model versions requires technical and policy evaluations to ensure 

the models meet regulatory requirements.”

8 See 76 FR 52431. “The commenter indicated that a revised version of the model is available and submitted modeling analyses 

using CALPUFF model Versions 6.112 and 6.4. The newer version(s) of CALPUFF have not received the level of review 

required for use in regulatory actions subject to EPA approval and consideration in a BART decision making process.”

9 See 77 FR 24066. “We have also considered an additional factor: The modeled visibility benefits of controls. We evaluated 

this factor for Colstrip Units 3 and 4, due to the size of Colstrip Units 3 and 4 in comparison with the other RP sources. For the 

more cost-effective option (SNCR), the modeled visibility benefits are relatively modest. For the more expensive option (SCR), 

the modeled visibility benefits, although more substantial, are not sufficient for us to consider it reasonable to impose this option 

in this planning period. Therefore, we are proposing that no additional NOX controls will be required for this planning period on 

Colstrip Unit 3.”
cost of compliance.

10 However, EPA has not established a threshold, required or recommended, 

below which such value is considered reasonable and above which it is considered unreasonable. 

As in the case of “subject-to” discussion above, careful consideration should be given to any 

benefit based metric to reflect the lower threshold necessary for cumulative consideration. 

Recommendations:

• Update EPA RP guidance to further emphasize collective or source category approach to 

future RP analyses; however, if single source approaches are used, update the guidance to 

better reflect analytical methods and metrics based upon the discussion above.

• Update EPA methods for calculating control costs.

• Develop an emissions control technology clearinghouse that provides summary of

engineering data for emissions control decisions related to regional haze.

• Provide guidance regarding when and how to consider visibility benefit of emissions

controls which reflects need for collective analysis.

 10 See EPA Guidance for Setting Reasonable Progress Goals Under the Regional Haze Program June 1, 2007. “Therefore, in 

assessing additional emissions reduction strategies for source categories or individual, large scale sources, simple cost 

effectiveness estimates based on a dollar-per-ton calculation may not be as meaningful as a dollar-per-deciview calculation, 

especially if the strategies reduce different groups of pollutants.”
IV. Promote Timely Submission of SIPs.

The first round of regional haze SIPs suffered from a protracted lack of timeliness. This was 

further complicated by lawsuits to compel EPA to first issue findings of failure to submit, and 

then three years later to either approve SIPs or promulgate FIPs. EPA and FLM resources were 

stretched by multiple years of SIP review, litigation, and multiple FIPs. Unlike the NAAQS SIP 

development requirements, the Regional Haze Rule did not encourage timely submittal and 

review of implementation plans. With only the occasional use of FIPs and casual mention of 

“discretionary sanctions” and no tangible regulatory backstop, there was no external impetus for 

states to submit their haze SIPs on time. We encourage EPA to explore using discretionary 

penalties for failure to submit.

The practical result of untimely submission of SIPs and subsequent court ordered deadlines was 

two-fold. First, due to a lack of interregional consistency in the application of BART guidelines 

and its underlying modeling and engineering principals, and also the hard deadlines imposed by 

the consent decree schedule, EPA was forced in a number of cases to either employ questionable 

analysis methods to support FIPs or adopt flawed state determinations outright.11 Second, in the 

collective rush to publish SIP approvals or FIPs by the court ordered deadlines, the normal FLM 

consultation process had to be reduced or abandoned altogether. 

We believe that the “default” alternative RP approach presented by USFWS and NPS on 

December 5, 2013, provides a unique alternative that could streamline the SIP development 

process and promote more timely submission of SIPs.

Recommendations:

• Promote RP “default” alternative as an “off-ramp” opportunity to States.

• Develop a team of regional haze practitioners to evaluate the elements of the Regional 

Haze rule that may consume resources with little benefit to SIP development.

• Consider use of discretionary sanctions associated with delayed SIP submission. 

 11 See 78 FR 8720. “The BART Guidelines instruct EPA to conduct modeling using CALPUFF or other appropriate dispersion 

models for each source and highlight the importance of source-specific features, such as stack flow rate and release height. EPA's 

use of ``visibility impact ratios'' derived from other sources is not consistent with EPA's own guidelines and provides results that 

are too unreliable for the purpose of a BART visibility analysis. In using the visibility impact ratio approach, EPA is holding 

itself to a lower standard than it would expect from a state air quality agency conducting a similar BART review.”
V. Clarification of Reasonable Attribution of Visibility Impairment 

(RAVI) Regulations 

40 CFR § 302 through 306 contain the reasonably attributable visibility impairment (RAVI) 

requirements to address visibility impairment from one or a small number of sources. While 

much of the focus of the regional haze process has been on the requirements contained at 40

CFR § 51.308, we would like to remind EPA that the RAVI provisions are currently in full effect 

and it is very important that they remain as such. We view these requirements as a critical 

backstop to address any source that is not addressed under 40 CFR § 51.308 requirements.

The plan requirements that come out of a RAVI certification are similar but distinctly different 

from 40 CFR § 51.308. For example, in previous rulemakings, EPA clearly recognized that best 

available retrofit technology (BART) under RAVI (40 CFR § 51.302) is different from regional 

haze BART (40 CFR § 51.308). EPA terms them “regional haze BART” and “RAVI BART” in 

language in the federal register. While regional haze BART is only done once, RAVI BART 

requirements at 40 CFR § 51.302(c)(1) state “The affected Federal Land Manager may certify to 

the State, at any time, that there exists reasonably attributable impairment of visibility in any 

mandatory Class I Federal area.” RAVI BART can change because the control technology 

determination is made at a certain point in time. As technology evolves, a source that previously 

found no applicable pollution control technology may later find one that is applicable. It is 

exactly this situation that is anticipated at 40 CFR § 51.302(c)(4)(v) where the Administrator 

may require a BART analysis “at such times... as new technology for control of the pollutant 

becomes reasonably available...”. EPA also anticipates the possibility of a RAVI certification 

coming after submittal of the plans required under 40 CFR § 51.308 and how the overall 

planning cycle would be addressed.

12,13

Further illustration of EPA thoughts on these issues is contained in the CSAPR better than 

BART final rule. 77 FR 33642states: “In light of the fact that our proposal did not request 

The clear differentiation between RAVI BART and RH 

BART was also seen in Minnesota where EPA approved Regional Haze BART for Xcel Sherco 

but specifically said they have not yet addressed BART for the RAVI certification.” 77 FR 3689

also states “The RAVI rules at 40 CFR 51.302(c) require the determination of emission limits 

representing BART for certified facilities. A BART determination under the RAVI is similar to, 

but independent from the BART determination made under the RHR. EPA views Minnesota’s 

submittal as addressing regional haze as regulated under 40 CFR 51.308 and not RAVI as 

regulated under 40 CFR 51.302 to 51.306. Therefore, this proposed rule only addresses 

satisfaction of regional haze requirements and does not address whether Minnesota’s plan 

addresses requirements that apply as a result of the certification of Sherco as a RAVI source. 

EPA will act on RAVI BART in a separate notice.”

 12 See 40 CFR § 51.306(c) 13 See 77 FR 3685.
comment on the interplay of the RAVI requirements in 40 CFR 51.302– 306 with the 

requirements of the Regional Haze Rule, we are not adopting any clarifying interpretation at this 

time. As a result, this rulemaking alters neither the authority of a federal land manager to certify 

reasonably attributable visibility impairment nor the obligation of states (or EPA) to respond to 

a RAVI certification under 40 CFR Part 51 Subpart P (Protection of Visibility). Whatever the 

form, we intend to provide an opportunity for public comment before applying a new 

interpretation. In this final action we are preserving the language in the regional haze 

regulations at 40 CFR 51.308(e)(4) that allows states to include in their SIPs geographic 

enhancements to the trading program to accommodate a situation where BART is required based 

on RAVI at a Class I area. We are not adopting any clarifying interpretation of this language at 

this time, but we expect at a later date to clarify the scope of the RAVI requirements through a 

rule amendment, general guidance, or action on a SIP or FIP in the context of a specific RAVI 

case.” 

Recommendations:

• In the spirit of cooperative rulemaking, please inform the Forest Service early on of any 

efforts within EPA to limit our authority under RAVI.