1

Appendix D-16

RESPONSE TO COMMENTS

August 2012

In February 2012, the Massachusetts Department of Environmental Protection (MassDEP)

proposed amendments to its December 30, 2011 Regional Haze State Implementation Plan (SIP)

to address Best Available Retrofit Technology (BART) requirements and other emission

reduction commitments for electric generating units (EGUs). MassDEP held public hearings and 

solicited oral and written testimony on the proposed SIP amendments in accordance with 

Massachusetts General Laws (M.G.L.) Chapter 30A. On February 21, 2012, MassDEP 

published notice of the public hearings and public comment period on the proposed amendments

in the Boston Globe and the Springfield Republican, and notified interested parties via electronic 

mail. Public hearings were held on March 27, 2012 in Springfield and on March 28, 2012 in 

Boston. No oral testimony was provided at either hearing. The public comment period closed on 

April 9, 2012. MassDEP received several sets of written comments. A summary of written 

comments received and MassDEP’s responses are provided below. 

Commenters: 

1. U.S. Department of the Interior, National Park Service, comments dated April 9, 2012 [NPS]

2. U.S. Department of Agriculture, Forest Service, comments dated April 9, 2012 [FS]

3. U.S. Environmental Protection Agency Region 1, comments dated April 4, 2012 [EPA]

4. Sierra Club, Massachusetts Sierra Club, and Conservation Law Foundation, comments dated 

April 9, 2012 [SC/CLF]

5. Dominion Energy New England, comments dated April 9, 2012 [Dominion]

1. Comment: MassDEP is proposing a Best Available Retrofit Technology (BART) Alternative 

that includes BART and non-BART EGUs. In a similar case regarding trading among BART 

and non-BART boilers, EPA required Wisconsin to follow EPA’s economic incentive program 

(EIP) guidance. We believe that MassDEP’s BART Alternative should be consistent with EPA’s 

EIP policy and demonstrate a 10% “environmental benefit.” [NPS]

Response: MassDEP’s Alternative to BART does not involve emissions trading between 

sources, and therefore EPA’s EIP policy is not applicable.

2. Comment: From the perspective of a Federal Land Manager, who has affirmative 

responsibility to protect the air quality related values in federal Class I areas, we are encouraged 

that a number of significant steps are being taken to reduce sulfur dioxide emissions. Some of 

the steps include the retirement of Somerset Power Unit 8 in 2010, the proposed retirement of 

Salem Harbor Units 3 and 4 in 2014, and MassDEP’s proposed amendments to its low sulfur fuel 

oil regulation (which would require EGUs that burn residual oil to limit the sulfur content to 

0.5% by weight beginning July 1, 2014). We also acknowledge your proposal to review EGU 

emissions in 2013, with the intent of a 90% reduction in sulfur dioxide emissions from EGUs 

from 2002 levels by 2018. (FS)
2

Response: MassDEP appreciates the Forest Service’s comments.

3. Comment: In Tables 16-19, for clarity, EPA suggests that the term “projected” be replaced 

with the term “estimated.” These emissions are not being projected for a specific future year, but 

are the estimated reduced emissions resulting from the application of either the BART 

benchmark or alternative BART. [EPA]

Response: MassDEP has made this change.

4. Comment: In Tables 17, 19, and 20, EPA recommends that MassDEP add a column which 

indicates the enforceable mechanism for the state SO2, NOx and PM10 emission limits,

respectively. [EPA]

Response: MassDEP has not added columns to the Tables due to limited space, but the 

enforceable mechanisms for the emission rates are described in the text surrounding these tables.

5. Comment: The first sentence of Section 8.11 states, “MassDEP’s proposed Alternative to 

BART does not cover PM10 emissions.” EPA recommends that this statement be clarified to 

indicate that for PM10, MassDEP undertook source-by-source BART determinations. [EPA]

Response: MassDEP has made this change.

6. Comment: MassDEP’s proposal includes several new Appendices, including one rule and 

several emissions control plan approvals. As these items are relied upon by MassDEP to 

implement BART, these Appendices need to be included in the final SIP revision and 

incorporated into the SIP. As such, if there are certain provisions of the rule or emission control 

plans that MassDEP does not want to be incorporated into the SIP, it should make that clear in 

the SIP revision. Conditions which MassDEP does not want to incorporate into the SIP should 

be struck out in the final submittal. [EPA]

Response: MassDEP has included the final emissions control plans (ECPs) and regulations it is 

relying on in the SIP as Appendices in the SIP, and has struck out those portions of the ECPs and

regulations it does not want incorporated into the SIP.

7. Comment: Since a number of new Tables are being added to Section 8.10 and 8.11 of the 

SIP, the tables contained in Sections 9 and 10 of the final SIP submitted in December should be 

revised. This includes the revised “Table 19: Massachusetts Targeted EGUs” in proposed 

Section 10.5, which should be renumbered as Table 25. The references to Table 19 on pages 16 

and 18 should likewise be changed to Table 25. [EPA]

Response: MassDEP has made these changes.

8. Comment: MassDEP’s proposed plan to address BART requirements for EGUs does not 

comply with the requirements of the Clean Air Act (CAA) and EPA’s implementing regulations, 

40 C.F.R. Pt. 51. MassDEP impermissibly seeks to rely on a handful of state regulations as an 

alternative to requiring source-specific BART emission limits for subject-to-BART EGUs in 
3

Massachusetts. However, not only does the plain language of the Clean Air Act preclude the use 

of such alternatives, but Massachusetts has also failed to meet its specific obligations under 

EPA’s regional haze regulations to justify the use of these regulations to replace source-specific 

BART limits. [SC/CLF]

Response: MassDEP believes its SIP complies with the Clean Air Act and EPA’s regional haze 

regulations. The Clean Air Act does not prohibit a state from developing an Alternative to 

BART program and EPA’s implementing regulations at 40 CFR 51.308(e)(2) specifically allow 

a state to adopt an Alternative to BART provided that such alternative achieves greater 

reasonable progress toward natural visibility conditions than source-by-source BART. 40 CFR 

51.308(e)(3) provides that an alternative program can be deemed to achieve greater reasonable 

progress than source-specific BART if the alternative program results in greater emission 

reductions, provided the geographic distribution of emissions is similar under the alternative 

measure and BART. EPA’s regulations allowing an Alternative to BART have been upheld by

the D.C. Circuit Court of Appeals. CEED v. EPA, 398 F.3d 653, 659-660 (D.C.Cir. 2005) In its 

SIP, MassDEP demonstrates that its Alternative to BART achieves greater emissions reductions 

than would source-specific BART, and that the distribution of emissions is similar. Therefore, 

MassDEP’s Alternative to BART achieves greater reasonable progress and meets the 

requirements of EPA’s regional haze regulations. 

9. Comment: MassDEP has not included or referenced in its SIP revision the statutorily

required source-by-source BART analysis for each emission unit subject to BART. 

Consequently, MassDEP cannot substantiate whether its proposed BART alternative results in 

greater reductions of haze-forming pollutants than would be achieved under source-by-source 

BART, as is required for MassDEP to rely on a BART alternative. EPA has promulgated 

detailed BART guidelines that lay out the five-step process that must be followed to determine 

BART for units at facilities with a capacity greater than 750 MW. MassDEP must follow that 

process here for Brayton Point, Canal, Mystic and Salem Harbor and must include these analyses 

in its SIP. In addition, for units at smaller facilities, the statute and regulations establish factors 

that MassDEP must consider in establishing BART. These analyses are missing from 

MassDEP’s proposed regional haze SIP, and this deficiency must be remedied before MassDEP 

can purport to rely on its proposed BART alternative. [SC/CLF]

Response: Under EPA’s regional haze regulations, if a state pursues an Alternative to BART 

program it must submit an analysis that includes a determination of BART for each source 

subject to BART and covered by the alternative as part of its SIP. However, there is one

exception to this requirement where the “...alternative measure has been designed to meet a 

requirement other than BART (such as the core requirement to have a long-term strategy to 

achieve the reasonable progress goals established by States). In this case, the State may

determine the best system of continuous emission control technology and associated emission 

reductions for similar types of sources within a source category based on both source-specific 

and category-wide information, as appropriate.” [see 40 CFR 308(e)(2)(i)(C)] MassDEP’s 

alternative BART measures were designed for purposes other than BART and are part of 

Massachusetts’ long-term strategy to meet reasonable progress goals. Therefore, EPA’s 

regulations allow MassDEP to establish a BART benchmark to compare to its Alternative to 
4

BART using assumptions for categories of sources, rather than determining source-specific 

BART for each BART-eligible source. 

10. Comment: In seeking to demonstrate that its proposed BART alternative produces 

emissions benefits relative to source-specific BART, MassDEP improperly compared emissions 

reductions under its proposed BART alternative to those under MANE-VU’s categorically 

derived presumptive BART. But presumptive BART is not BART, and is not a substitute for 

analyses that comply with the regional haze rule and BART guidelines for each subject-to-BART 

source. Because source-specific BART limits are often significantly lower than those identified 

by EPA as presumptive BART, MassDEP’s comparison of its BART alternative to presumptive 

BART is impermissibly skewed in favor of the BART alternative. MassDEP must redo its 

analysis and compare emission reductions under the proposed alternative to those produced by

full source-specific BART analyses. MassDEP must include in this analysis an evaluation of the 

impact of source-specific emission reductions on each affected Class I area. [SC/CLF]

Response: As noted in the response to Comment 9, EPA’s regional haze regulations allow 

MassDEP to establish a BART benchmark to compare to its Alternative to BART based on an 

analysis that includes simplifying assumptions about BART control levels for sources within a 

source category, rather than determining source-specific BART for each BART-eligible source. 

At a minimum, MassDEP believes its BART benchmark should be based on EPA’s presumptive 

limits for EGUs in its BART Guidelines. However, MassDEP has gone beyond EPA’s 

presumptive BART Guidelines and based its BART benchmark on MANE-VU’s more stringent 

recommended BART emission limits for EGUs. Therefore, MassDEP’s BART benchmark 

appropriately and adequately represents what BART is likely to be for the category of EGU 

sources.

11. Comment: MassDEP cannot establish that its proposed BART alternative results in greater 

reasonable progress toward achieving natural baseline visibility conditions in Class I areas than 

would properly conducted source-by-source BART. MassDEP’s comparison of the sulfur 

dioxide (SO2) and nitrogen oxide (NOx) emission reductions under its proposed alternative and 

source-specific BART is fatally flawed because the agency ignores emission reductions already

being achieved at subject-to-BART units and ignores enforceable emission reductions at units 

subject to its BART alternative that should be included as well in the source-specific BART 

benchmark case. The BART emissions benchmarks for SO2 and NOx included in Tables 16 and 

18 of the SIP appear to significantly under predict emission reductions that would be achieved 

under properly conducted source-specific BART. For example, Brayton Point Units 1 and 2 

already are achieving SO2 emissions rates that are lower than the presumptive BART emission 

rate of 0.15 lb/MMBtu that MassDEP assumed in its BART Benchmark, so that emissions from 

these two units should be at most 1,811 tons, not 2,467 tons as MassDEP presumes, an 

overestimate of 656 tons. Brayton Point Unit 3 is installing a dry scrubber that could result in 

emissions of 778 tons, compared to the 2,725 tons of SO2 presumed by MassDEP, which is an 

overestimate of 1,947 tons. In addition, MassDEP credits its BART alternative with 9,998 tons 

of SO2 reductions from Salem Harbor Units 1, 2 and 3. This is improper since each of these units 

is subject to an enforceable consent decree between Conservation Law Foundation, Healthlink, 

and Dominion requiring the complete shutdown of Salem Harbor as a coal-fired power plant no 

later than June 1, 2014. Consequently, these emission reductions would have occurred under the 
5

source-specific BART scenario just as they occur in MassDEP’s BART alternative. MassDEP 

therefore cannot consider the emissions reductions occurring at Salem Harbor Units 1 through 3 

only for its BART alternative, but must include the enforceable emission reductions for these 

units in its analysis of source-specific BART as well.

Likewise for NOx, MassDEP underestimates the emission reductions that would be achieved

under source-specific BART and improperly credits it proposed BART alternative with 

achieving thousands of tons of NOx reductions from Salem Harbor that would occur under either 

scenario. In addition, MassDEP has not provided sufficient information in its regional haze SIP 

to evaluate or eliminate selective catalytic reduction (SCR) or selective non-catalytic reduction 

(SNCR) as control technologies for NOx at Brayton Point Unit 2.

Correcting these errors reveals that in 2018 source-specific BART would result in SO2 emissions 

reductions at least 8,600 tons greater than under the BART alternative and NOx emissions at 

least 3,200 tons greater than under MassDEP’s proposed alternative to BART. Consequently, 

MassDEP cannot demonstrate that its proposed BART alternative would result in greater 

reasonable progress toward achieving natural baseline visibility conditions in the areas protected 

by the regional haze rule, and MassDEP’s BART alternative fails to meet the basic requirements 

of 40 CFR 51.308(e)(2). [SC/CLF]

Response: These comments assert that MassDEP significantly underestimated emissions 

reductions for SO2 and NOx in its BART benchmark, which assumes that the BART benchmark 

must be based on a source-specific BART determination for each BART-eligible source. 

However, as noted in the responses to Comments 9 and 10, the BART benchmark does not 

require a source-specific BART determination for each BART-eligible source, but may be based 

on an analysis that includes simplifying assumptions about BART control levels for sources 

within the source category being considered (i.e., EGUs). This is the case even if existing 

controls or future controls (including shutdowns) could result in more emissions reductions than 

estimated by the BART benchmark. The preamble to EPA’s 2006 regional haze regulations (71 

FR 60612) includes the following language that makes clear that source-specific BART 

determinations are not required under the Alternative to BART that MassDEP has established in 

its SIP, and that states may use EPA’s presumptive BART limits in establishing a BART 

benchmark:

“In today's final rule, the regulations make clear that, with one exception, States must 

follow the approach for making BART determinations under section 51.308(e)(1) in 

establishing a BART benchmark. This includes the requirement for States to use the 

BART guidelines in making BART determinations for EGUs at power plants of a 

certain size. As discussed above, the one exception to this general approach is where 

the alternative program has been designed to meet requirements other than BART; in 

this case, States are not required to make BART determinations under § 

51.308(e)(1) and may use simplifying assumptions in establishing a BART 

benchmark based on an analysis of what BART is likely to be for similar types of 

sources within a source category. [emphasis added] Under either approach to 

establishing a BART benchmark, we believe that the presumptions for EGUs in the 

BART guidelines should be used for comparison to a trading program or other 
6

alternative measure, unless the State determines that such presumptions are not 

appropriate for particular EGUs. We note that this limitation on the use of the 

presumptions is most likely to apply only in a source-by-source determination under § 

51.308(e)(1). States establishing a BART benchmark based on simplifying 

assumptions as to the most-stringent BART for EGUs may rely on the 

presumptions, as EPA did in the CAIR rule.” [emphasis added]

12. Comment: The Massachusetts SIP revision fails to demonstrate that the distribution of 

emission reductions under its proposed BART alternative will be similar to that under sourcespecific BART or conduct dispersion modeling showing that the BART alternative results in 

greater reasonable progress in areas protected by the regional haze rule. Although MassDEP 

asserts that the distribution of emissions is similar, its rationale is flawed and a further 

demonstration is required. Under EPA’s haze regulations, it is insufficient to simply compare 

the total emissions reductions from source-specific BART and a state’s BART alternative; the

state must also take into consideration the location of these emission reductions. Where the 

distribution of emissions under BART and the alternative are substantially different, the state 

proposing to rely on a BART-alternative must conduct dispersion modeling to show the 

difference in visibility under each program for each impacted Class I area on the worst and best 

20 percent of days. The modeling will demonstrate greater reasonable progress only if: (1) 

Visibility does not decline in any Class I area; and (2) There is an overall improvement in 

visibility, determined by comparing the average differences between BART and the alternative 

over all affected Class I areas. MassDEP does not offer dispersion modeling to compare the 

visibility improvements resulting from source-specific BART and its proposed BART 

alternative. Instead the agency claims that “the Alternative to BART achieves greater emissions 

reductions than BART and the geographic distribution of emissions reductions is nearly identical 

since all of the units subject to BART are included in the Alternative to BART.” But this 

reasoning is flawed. The mere fact that the subject-to-BART units are a subset of the alternative 

BART units says nothing about the similarity of emission reduction distributions under each 

scheme. Instead, to assess emission distributions MassDEP would have to compare the 

magnitude of emission reductions at units common to both schemes and evaluate whether the 

additional units covered by the BART alternative are proximate to subject to BART sources. 

MassDEP has not done so, and therefore cannot presume that its BART alternative produces a 

similar distribution of emission reductions. [SC/CLF]

Response: MassDEP believes that the geographic distribution of the emissions reductions from 

the Alternative to BART is not significantly different to the geographic distribution of emissions 

reductions from source-specific BART, and therefore comparison of the Alternative to BART 

and BART benchmark may be made on the basis of emissions alone in accordance with 40 CFR 

51.308(e)(3). The Table below shows the geographic distribution of SO2 and NOx emission

reductions for the BART benchmark and Alternative to BART. With the exception of emissions 

reductions at Mt. Tom in Western Massachusetts (which will help reduce visibility impacts at the 

Lye Brook Class I area in Vermont), all of the emission reductions that result from MassDEP’s 

Alternative to BART occur in Eastern Massachusetts, which is the same geographic area where 

emissions reductions would occur from source-specific BART (represented by the BART 

benchmark). On this basis alone, MassDEP believes that the distribution of emissions reductions 

is similar between the two approaches given the relatively small size of Massachusetts in the 
7

context of regional haze, which is visibility impairment produced by a multitude of sources and 

activities located across a broad geographic area. The Alternative to BART results in a greater 

portion of overall emissions reductions in Northeast MA versus Southeast MA, compared to the 

BART benchmark, which could be beneficial since Northeast MA is closer in distance to the 

MANE-VU Class I areas. It should be noted that while the BART modeling performed by 

MANE-VU showed that emissions from Southeast MA had the greatest visibility impact at Class 

I areas in Maine (due to Brayton Point and Canal), the modeling of emissions from Northeast 

MA did not include Salem Harbor Units 1-3 because they are not BART units. Had emissions 

from Salem Harbor Units 1-3 been included in the MANE-VU BART modeling, the impact from 

Northeast MA would have been greater than reported in the original modeling. 

SO2 Emissions Reductions (in tons)

Geographic Region BART Benchmark Alternative to BART

Northeast MA 3,097 12,363

Southeast MA 47,655 38,912

Western MA 0 3,710

Total 50,752 54,986

NOx Emissions Reductions (in tons)

Geographic Region BART Benchmark Alternative to BART

Northeast MA 526 2,376

Southeast MA 12,294 9,557

Western MA 0 1,184

Total 12,820 13,117

Notes: Northeast MA includes Salem Harbor and Mystic

Southeast MA includes Brayton Point, Canal, Somerset, and Cleary Flood

Western MA includes Mt. Tom

Totals shown may not add precisely due to rounding

13. Comment: MassDEP has not demonstrated that the state will achieve the reasonable 

progress goals established by MANE-VU for 2018. MANE-VU includes as a reasonable 

progress goal emission reductions of 90% from each of the 167 power plant stacks in the 

MANE-VU region whose SO2 emissions were determined to significantly impair visibility in 

one or more MANE-VU Class I areas. The Massachusetts regional haze SIP fails to put the state 

on a path to achieve those reductions, even under the optimistic projections made by MassDEP, 

and fails to require enforceable commitments to achieve these reductions. Where a state has 

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

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

process.” 40 C.F.R. § 51.308(d)(3)(ii). However, under MassDEP’s proposed SIP, the state is 

not projected to achieve the 90% SO2 reduction target by 2018 at major EGUs. Instead, 

MassDEP projects emission reductions of between 67 and 87% from the affected units. This is 

unacceptable given its regulatory obligation, and particularly in light of the levels of SO2 

emissions cost-effectively achievable from these units. To remedy this deficiency, the SIP at a 

minimum should include enforceable requirements that Mount Tom and Brayton Point operate 

their sulfur dioxide controls continuously and require an enforceable SO2 emission limit of zero 

for Salem Harbor Units 1 and 2 consistent with the consent decree requiring the shutdown of the 
8

Salem Harbor facility as a coal-fired power plant. When coupled with an enforceable shutdown 

of all units at Salem Harbor and the shutdown of Somerset Unit 8, the requirement of continuous 

operation of SO2 controls at Brayton Point and Mount Tom should enable Massachusetts to meet 

its obligation of achieving an enforceable 90% reduction in SO2 emissions from the stacks 

covered by the MANE-VU reasonable progress goal. [SC/CLF]

Response: As a point of clarification, the MANE-VU commitment to a 90% reduction in SO2 

emissions from 167 EGU stacks is not a reasonable progress goal, but is part of the long-term 

strategy MANE-VU states adopted to achieve the reasonable progress goals established by the 

Class I states (the reasonable progress goals for the Class I areas are described in Section 9 of the 

SIP). In addition, the MANE-VU commitment provides flexibility in achieving the emission 

reductions that were assumed for each state in the modeling that formed the basis of the 

reasonable progress goals. MassDEP has demonstrated that its long-term strategy includes all 

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

through the regional planning process, in accordance with 40 CFR 51.308(d)(3)(ii). Regarding 

the 167 EGU strategy, as described on page 18 of the proposed SIP revision, MassDEP’s 

conservative 67% reduction projection for targeted EGUs results in 26,811 tons of SO2 emissions 

in 2018, which is well below the 45,941 tons of SO2 emissions that Massachusetts needs to meet 

the modeled 2018 reasonable progress goals for the Class I areas. Therefore, MassDEP has met 

the requirement of 40 CFR 51.308(d)(3)(ii) with regard to EGU emissions even under its most 

conservative projection. Fortunately, MassDEP projects that EGU SO2 emissions reductions in 

2018 will be much lower, by 87% or more. 

14. Comment: We agree with MassDEP’s proposed revisions to the Massachusetts Regional 

Haze SIP and urge you to finalize them as proposed with regard to the Amended Emission 

Control Plan Draft Approvals for Salem Harbor and Brayton Point. In particular, we also 

support MassDEP’s Alternative to BART approach as part of the proposed revisions. Based on 

the provisions of 40 CFR 51.308(e)(2), we agree that Massachusetts has the authority to 

implement the proposed Alternative to BART. Furthermore, as shown in section 8.10 of the 

proposed SIP revision, MassDEP has demonstrated its alternative to BART will achieve greater

emission reductions of SO2 and NOx than would be achieved through the installation and 

operation of BART alone. The Proposed Revision to the SIP also addresses BART for PM10. 

However, MassDEP has determined that no additional controls are warranted for primary PM10 

because controls have been added to all but one of the (non-Dominion) facilities, and the 

additional cost of further control is not justified since there would be no significant visibility

improvement. [Dominion]

Response: MassDEP has finalized the Amended Emission Control Plans for Salem Harbor and 

Brayton Point as proposed in the SIP revision. In addition, MassDEP has adopted its Alternative 

to BART as proposed.