[Federal Register Volume 84, Number 153 (Thursday, August 8, 2019)]
[Proposed Rules]
[Pages 38898-38905]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-17000]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R01-OAR-2019-0353; FRL-9997-89-Region 1]


Air Plan Approval; Massachusetts; Transport Element for the 2010 
Sulfur Dioxide National Ambient Air Quality Standard

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve the State Implementation Plan (SIP) submission from the 
Commonwealth of Massachusetts addressing the Clean Air Act (CAA or Act) 
interstate transport SIP requirements, referred to as the good neighbor 
provision, for the 2010 sulfur dioxide (SO2) national 
ambient air quality standards (NAAQS). This submission addresses the 
interstate transport requirements of the CAA that

[[Page 38899]]

the SIP contain adequate provisions prohibiting air emissions from 
Massachusetts from having certain adverse air quality effects in other 
states. In this action, the EPA is proposing to approve this portion of 
the infrastructure SIP submission that certifies that the Massachusetts 
SIP contain adequate provisions to ensure that air emissions in the 
Commonwealth will not significantly contribute to nonattainment or 
interfere with maintenance of the 2010 SO2 NAAQS in any 
other state.

DATES: Written comments must be received on or before September 9, 
2019.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R01-
OAR-2019-0353 at https://www.regulations.gov, or via email to 
hubbard.elizabeth@epa.gov. For comments submitted at Regulations.gov, 
follow the online instructions for submitting comments. Once submitted, 
comments cannot be edited or removed from Regulations.gov. For either 
manner of submission, the EPA may publish any comment received to its 
public docket. Do not submit electronically any information you 
consider to be Confidential Business Information (CBI) or other 
information whose disclosure is restricted by statute. Multimedia 
submissions (audio, video, etc.) must be accompanied by a written 
comment. The written comment is considered the official comment and 
should include discussion of all points you wish to make. The EPA will 
generally not consider comments or comment contents located outside of 
the primary submission (i.e., on the web, cloud, or other file sharing 
system). For additional submission methods, please contact the person 
identified in the FOR FURTHER INFORMATION CONTACT section. For the full 
EPA public comment policy, information about CBI or multimedia 
submissions, and general guidance on making effective comments, please 
visit http://www.epa.gov/dockets/commenting-epa-dockets. Publicly 
available docket materials are available at https://www.regulations.gov 
or at the U.S. Environmental Protection Agency, EPA Region 1 Regional 
Office, Air and Radiation Division, 5 Post Office Square--Suite 100, 
Boston, MA. The EPA requests that if at all possible, you contact the 
contact listed in the FOR FURTHER INFORMATION CONTACT section to 
schedule your inspection. The Regional Office's official hours of 
business are Monday through Friday, 8:30 a.m. to 4:30 p.m., excluding 
legal holidays.

FOR FURTHER INFORMATION CONTACT: Elizabeth Hubbard, Air Quality Branch, 
U.S. Environmental Protection Agency, EPA Region 1, 5 Post Office 
Square--Suit 100, (Mail code 05-2), Boston, MA 02109--3912, tel. (617) 
918-1614, email hubbard.elizabeth@epa.gov.

SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,'' 
``us,'' or ``our'' is used, we mean the EPA.

Table of Contents

I. Background and Purpose
II. Relevant Factors To Evaluate 2010 SO2 Interstate 
Transport SIPs
III. Massachusetts's Submission and the EPA's Analysis
    A. Massachusetts's Analysis
    B. The EPA's Prong 1 Evaluation--Significant Contribution to 
Nonattainment
    C. The EPA's Prong 2 Evaluation--Interference With Maintenance 
of the NAAQS
IV. Proposed Action
V. Statutory and Executive Order Reviews

I. Background and Purpose

    On June 2, 2010, the EPA established a new primary 1-hour 
SO2 NAAQS of 75 parts per billion (ppb), based on the 3-year 
average of the annual 99th percentile of 1-hour daily maximum 
concentrations.\1\ Whenever the EPA promulgates a new or revised NAAQS, 
CAA section 110(a)(1) requires states to make SIP submissions to 
provide for the implementation, maintenance, and enforcement of the 
NAAQS. This particular type of SIP submission is commonly referred to 
as an ``infrastructure SIP.'' These submissions must meet the various 
requirements of CAA section 110(a)(2), as applicable. Due to ambiguity 
in some of the language of CAA section 110(a)(2), the EPA believes that 
it is appropriate to interpret these provisions in the specific context 
of acting on infrastructure SIP submissions. The EPA has previously 
provided comprehensive guidance on the application of these provisions 
through a guidance document for infrastructure SIP submissions and 
through regional actions on infrastructure submissions.\2\ Unless 
otherwise noted below, we are following that existing approach in 
acting on this submission. In addition, in the context of acting on 
such infrastructure submissions, the EPA evaluates the submitting 
state's SIP for facial compliance with statutory and regulatory 
requirements, not for the state's implementation of its SIP.\3\ The EPA 
has other authority to address any issues concerning a state's 
implementation of the rules, regulations, consent orders, etc. that 
comprise its SIP. One of these applicable infrastructure elements, CAA 
section 110(a)(2)(D)(i), requires SIPs to contain ``good neighbor'' 
provisions to prohibit certain adverse air quality effects on 
neighboring states due to interstate transport of pollution.
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    \1\ 75 FR 35520 (June 22, 2010).
    \2\ The EPA explains and elaborates on these ambiguities and its 
approach to address them in its September 13, 2013 Infrastructure 
SIP Guidance (available at https://www3.epa.gov/airquality/urbanair/sipstatus/docs/Guidance_on_Infrastructure_SIP_Elements_Multipollutant_FINAL_Sept_2013.pdf), as well as in numerous agency actions, including the EPA's 
prior action on Massachusetts's infrastructure SIP to address the 
1997 ozone, 2008 lead, 2008 ozone, 2010 NO2, and 2010 
SO2 NAAQS (see 81 FR 93627, December 21, 2016).
    \3\ See U.S. Court of Appeals for the Ninth Circuit decision in 
Montana Environmental Information Center v. EPA, No. 16-71933 (Aug. 
30, 2018).
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    Section 110(a)(2)(D)(i) includes four distinct components, commonly 
referred to as ``prongs,'' that must be addressed in infrastructure SIP 
submissions. The first two prongs, which are codified in section 
110(a)(2)(D)(i)(I), require SIPs to contain adequate provisions that 
prohibit any source or other type of emissions activity in one state 
from contributing significantly to nonattainment of the NAAQS in 
another state (prong 1) and from interfering with maintenance of the 
NAAQS in another state (prong 2). The third and fourth prongs, which 
are codified in section 110(a)(2)(D)(i)(II), require SIPs to contain 
adequate provisions that prohibit emissions activity in one state from 
interfering with measures required to prevent significant deterioration 
of air quality in another state (prong 3) or from interfering with 
measures to protect visibility in another state (prong 4).
    In this action, the EPA is proposing to approve the February 9, 
2018 Massachusetts submission, which certifies that the Commonwealth's 
infrastructure SIP contains adequate provisions related to prong 1 and 
prong 2, i.e., to ensure that air emissions in the Commonwealth will 
not significantly contribute to nonattainment or interfere with 
maintenance of the 2010 SO2 NAAQS in any other state. All 
other applicable infrastructure SIP requirements for the 2010 
SO2 NAAQS have been addressed in a separate rulemaking.\4\
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    \4\ See the EPA's final action on other elements of 
Massachusetts's SIP for the 2010 SO2 NAAQS at 81 FR 93627 
(December 21, 2016).
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II. Relevant Factors To Evaluate 2010 SO2 Interstate Transport SIPs

    Although SO2 is emitted from a similar universe of point 
and nonpoint sources as is directly emitted PM2.5 and the 
precursors to ozone and PM2.5,

[[Page 38900]]

interstate transport of SO2 is unlike the transport of 
PM2.5 or ozone because SO2 emissions sources 
usually do not have long range SO2 impacts. The transport of 
SO2 relative to the 1-hour NAAQS is more analogous to the 
transport of Pb relative to the Pb NAAQS in that emissions of 
SO2 typically result in 1-hour pollutant impacts of possible 
concern only near the emissions source. However, ambient 1-hour 
concentrations of SO2 do not decrease as quickly with 
distance from the source as do 3-month average concentrations of Pb, 
because SO2 gas is not removed by deposition as rapidly as 
are Pb particles and because SO2 typically has a higher 
emissions release height than Pb. Emitted SO2 has wider 
ranging impacts than emitted Pb, but it does not have such wide-ranging 
impacts that treatment in a manner similar to ozone or PM2.5 
would be appropriate. Accordingly, while the approaches that the EPA 
has adopted for ozone or PM2.5 transport are too regionally 
focused, the approach for Pb transport is too tightly circumscribed to 
the source. SO2 transport is therefore a unique case and 
requires a different approach.
    In SO2 transport analyses, we focus on a 50 km-wide zone 
because the physical properties of SO2 result in relatively 
localized pollutant impacts near an emissions source that drop off with 
distance. Given the physical properties of SO2, the EPA 
selected the ``urban scale''--a spatial scale with dimensions from 4 to 
50 kilometers (km) from point sources--given the usefulness of that 
range in assessing trends in both area-wide air quality and the 
effectiveness of large-scale pollution control strategies at such point 
sources.\5\ Furthermore, the American Meteorological Society/
Environmental Protection Agency Regulatory Model (AERMOD) is the EPA's 
preferred modeling platform for regulatory purposes for near-field 
dispersion of emissions for distances up to 50 km (Appendix W to 40 CFR 
part 51). As such, the EPA utilized an assessment up to 50 km from 
point sources in order to assess trends in area-wide air quality that 
might impact downwind states.
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    \5\ For the definition of spatial scales for SO2, 
please see 40 CFR part 58, Appendix D, section 4.4 (``Sulfur Dioxide 
(SO2) Design Criteria''). For further discussion on how 
the EPA is applying these definitions with respect to interstate 
transport of SO2, see the EPA's proposal on Connecticut's 
SO2 transport SIP. 82 FR 21351, 21352, and 21354 (May 8, 
2017).
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    As discussed in Section III of this proposed action, the EPA first 
reviewed Massachusetts's analysis to assess how the Commonwealth 
evaluated the transport of SO2 to other states, the types of 
information the Commonwealth used in the analysis, and the conclusions 
drawn by the Commonwealth. The EPA then conducted a weight of evidence 
analysis, including review of the Massachusetts submission and other 
available information, including ambient air quality data, data from 
SO2 emission sources, and emission trends within the 
Commonwealth and neighboring states to which it could potentially 
contribute or interfere.

III. Massachusetts's Submission and the EPA's Analysis

    In this section, we provide an overview of Massachusetts's 2010 
SO2 transport analysis included in its February 9, 2018 
submission that addresses the interstate transport requirements of CAA 
section 110(a)(2)(D)(i)(I), as well as the EPA's evaluation of prongs 1 
and 2.

A. Massachusetts's Analysis

    Massachusetts conducted a weight of evidence analysis to examine 
whether SO2 emissions from Massachusetts significantly 
contribute to nonattainment or interfere with maintenance of the 2010 
SO2 NAAQS in neighboring and downwind states. Massachusetts 
evaluated air monitoring data from ambient air monitoring stations in 
Massachusetts, as well in neighboring and downwind states. 
Massachusetts assessed whether SO2 emissions from sources 
located within 50 km of Massachusetts's borders may have contributed 
significantly to nonattainment or interfered with maintenance in 
neighboring and downwind states. Massachusetts's analysis included 
source-specific SO2 emissions data from Massachusetts 
sources located within 50 km of Massachusetts's border and having 
SO2 emissions over 100 tons per year (tpy). Massachusetts 
included the most recent stationary source SO2 emissions 
data, which was from 2015. These sources included: Brayton Point Energy 
LLC (1446 tpy SO2, located 2 km from the Rhode Island 
border), which shutdown in 2017; Mystic Station (729 tpy 
SO2, located 39 km from the New Hampshire border); Solutia 
Inc (523 tpy SO2, located 13 km from the Connecticut 
border), which permanently switched from coal to natural gas in 2016; 
NRG Canal LLC (492 tpy SO2, located 53 km to Rhode Island 
border); Wheelabrator Millbury Inc (224 tpy SO2, located 20 
km from the Connecticut border); SEMASS Partnership (192 tpy 
SO2, located 32 km to the Rhode Island border); and Veolia 
Energy Boston Inc (117 tpy SO2, located 43 km from the New 
Hampshire border).
    The largest SO2 point source in Massachusetts, Brayton 
Point Energy LLC, permanently ceased operations in 2017. Massachusetts 
noted that SO2 emissions have declined in the last 15 years, 
and that SO2 levels at all monitors in the Commonwealth are 
below the 75 ppb SO2 NAAQS. The Massachusetts Department of 
Environmental Protection (MassDEP) certifies that sources in 
Massachusetts do not contribute to nonattainment or interfere with 
maintenance of attainment of the 2010 SO2 NAAQS in any 
neighboring state.

B. The EPA's Prong 1 Evaluation--Significant Contribution to 
Nonattainment

    The EPA has analyzed the ambient air quality data, data from 
SO2 emission sources, distance from neighboring states, and 
emissions trends in Massachusetts and neighboring and downwind states, 
i.e., Connecticut, Maine, New Hampshire, New York, Rhode Island, and 
Vermont.\6\ Based on that analysis and discussed in greater detail 
below, the EPA proposes to find that Massachusetts's SIP meets the 
interstate transport requirements of CAA section 110(a)(2)(D)(i)(I), 
prong 1 for the 2010 NAAQS, and Massachusetts will not significantly 
contribute to nonattainment of the 2010 SO2 NAAQS in any 
other state.
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    \6\ For this analysis, though Maine does not share a border with 
Massachusetts, the EPA is analyzing SO2 transport impacts 
of Massachusetts sources on ambient air in Maine, because Maine is 
located approximately 24 km from Massachusetts at its nearest point.
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    Table 1 includes the most recent air quality design value for each 
active SO2 monitor in Massachusetts or in a neighboring or 
downwind state within 50 km of the Massachusetts border. These monitors 
were reviewed to see if there are any sites that show elevated 
SO2 concentrations which may warrant further investigation 
with respect to interstate transport of SO2 from 
Massachusetts emission sources near any given monitor.

[[Page 38901]]



                Table 1--SO2 Monitor Values in Massachusetts and Neighboring and Downwind States
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                                                                                    Distance to      2016-2018
                       State/city or town                             Site ID      Massachusetts   design value
                                                                                  border  (km) *   (ppb)[dagger]
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Connecticut/Cornwall............................................     09-005-0005              25               2
Massachusetts/Fall River........................................     25-005-1004               2               7
Massachusetts/Ware..............................................     25-015-4002              31               3
Massachusetts/Boston............................................     25-025-0002              41               3
Massachusetts/Boston............................................     25-025-0042              43               4
Massachusetts/Worcester.........................................     25-027-0023              26               4
New Hampshire/Peterborough......................................     33-011-5001              18               2
New Hampshire/Suncook...........................................     33-013-1006              46              14
New Hampshire/Portsmouth........................................     33-015-0014              24              13
New Hampshire/Londonderry.......................................     33-015-0018              17               3
New York/Loudonville............................................     36-001-0012              41               3
New York/Millbrook..............................................     36-027-0007              36               2
Rhode Island/East Providence....................................     44-007-1010               2               3
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* All distances throughout this notice are approximations.
[dagger] Data retrieved from the EPA's https://www.epa.gov/air-trends/air-quality-design-values#report on July
  24, 2019.

    As seen in the Table 1, there are no violating monitored design 
values in Massachusetts or neighboring or downwind states. The data 
presented in Table 1 show that Massachusetts's network of 
SO2 monitors with data sufficient to produce valid 1-hour 
SO2 design values that monitored 1-hour SO2 
levels in Massachusetts range between 4% and 10% of the 75 ppb level of 
the NAAQS. As shown above, all five Massachusetts SO2 
monitors are located within 50 km of a neighboring state's border. 
Seven monitors with data sufficient to calculate a design value for the 
2016-2018 period in neighboring or downwind states are located within 
50 km of the Massachusetts border, and these monitors recorded 
SO2 design values ranging between 2% and 19% of the 2010 
SO2 NAAQS. Thus, these air quality data do not, by 
themselves, indicate any particular location that would warrant further 
investigation with respect to SO2 emission sources that 
might significantly contribute to nonattainment in neighboring states. 
However, the monitoring network is not necessarily designed to find all 
locations of high SO2 concentrations. Therefore, this 
observation indicates an absence of evidence of impact at monitored 
locations, but is not sufficient evidence by itself of an absence of 
impact at all locations in the neighboring and downwind states. Given 
this, the EPA has also conducted a source-oriented analysis.
    As mentioned previously, the EPA finds that it is appropriate to 
examine the impacts of emissions from stationary sources in 
Massachusetts in distances ranging from 0 km to 50 km from the source. 
The EPA assessed point sources up to 50 km from state borders to 
evaluate trends and SO2 concentrations in area-wide air 
quality. The list of sources with 2015 emissions equal to or greater 
than 100 tpy \7\ SO2 within 50 km from Massachusetts borders 
is shown in Table 2, based on Massachusetts's submission. The EPA has 
also included 2017 SO2 emissions for those sources in the 
table, which were collected from MassDEP and transmitted to the EPA for 
incorporation into the National Emissions Inventory (NEI).
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    \7\ Massachusetts limited its analysis to Massachusetts sources 
of SO2 emitting at least 100 tpy in 2015. We agree with 
Massachusetts's choice to limit its analysis in this way, because in 
the absence of special factors, for example the presence of a nearby 
larger source or unusual factors, Massachusetts sources emitting 
less than 100 tpy can appropriately be assumed to not be causing or 
contributing to SO2 concentrations above the NAAQS. The 
EPA recognizes that in 2017 Ardagh Glass Inc. emitted 92 tpy 
SO2, with the next highest source (Wheelabrator Saugus 
Inc) emitting 54 tpy SO2. Ardagh Glass Inc. has 
permanently ceased operations as of September 26, 2018. Given these 
facts, the EPA finds MassDEP's analysis of SO2 sources 
above 100 tpy adequate for analysis of SO2 transport 
impacts to neighboring and downwind states.

          Table 2--Massachusetts SO2 Sources Greater Than 100 TPY Near Neighboring and Downwind States
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                                                                                                  2017 emissions
                                                                                  Distance (km)   (tons) for the
                                                                                   to nearest         nearest
                                   2015 SO2        2017 SO2       Distance to      neighboring    neighboring or
     Massachusetts source          emissions       emissions     Massachusetts  state SO2 source  downwind state
                                    (tons)          (tons)       border  (km)     emitting over       source
                                                                                100 tons in 2017   emitting over
                                                                                                    100 tons *
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Brayton Point Energy LLC (shut           1,446             552               2  150 (Public                  263
 down in May 2017).                                                              Service of New
                                                                                 Hampshire
                                                                                 (PSNH) Schiller
                                                                                 Station--Portsm
                                                                                 outh, New
                                                                                 Hampshire).
Mystic Station................             729             354              39  82 (PSNH                     263
                                                                                 Schiller
                                                                                 Station--Portsm
                                                                                 outh, New
                                                                                 Hampshire).
SEMASS Partnership............             192             301              32  140 (PSNH                    263
                                                                                 Schiller
                                                                                 Station--Portsm
                                                                                 outh, New
                                                                                 Hampshire).
Solutia Inc (ceased burning                523               0              13  104 (Monadnock               101
 coal as of December 2016).                                                      Paper Mills
                                                                                 Inc--Bennington
                                                                                 , New
                                                                                 Hampshire).
Veolia Energy Boston Inc......             117               0              43  85 (PSNH                     263
                                                                                 Schiller
                                                                                 Station--Portsm
                                                                                 outh, New
                                                                                 Hampshire).

[[Page 38902]]

 
Wheelabrator Millbury Inc.....             224             187              20  88 (PSNH                     263
                                                                                 Schiller
                                                                                 Station--Portsm
                                                                                 outh, New
                                                                                 Hampshire).
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* Emissions data were obtained using the EPA's 2017 NEI Draft.

    Table 2 shows the distance from each Massachusetts source emitting 
at least 100 tpy SO2 in 2015 to the nearest out-of-state 
source emitting at least 100 tpy of SO2 in 2017. As shown, 
six facilities in Massachusetts are within 50 km of the border with 
another state and are at a distance of 82 km or greater from the 
nearest out-of-state SO2 source emitting over 100 tpy. The 
nearest SO2 source emitting greater than 100 tpy in 
Massachusetts to a neighboring state, Brayton Point Energy LLC (2 km 
from Rhode Island), permanently ceased operations on May 31, 2017. 
Solutia Inc (13 km from Connecticut) converted its coal-fired unit to 
natural gas in 2016 and is no longer permitted to burn fuels that would 
result in emissions equal to or greater than 100 tpy. The EPA has 
reviewed the data Massachusetts submitted and agrees with the 
determination that the closure of Brayton Point Energy LLC and fuel 
switching at Solutia Inc have significantly lowered SO2 
emissions in Massachusetts and are not having downwind impacts in 
violation of prongs 1 and 2.
    For the remaining active Massachusetts point sources emitting over 
100 tpy of SO2, i.e., Mystic Station, SEMASS Partnership, 
Veolia Energy Boston Inc, and Wheelabrator Millbury Inc, the nearest 
SO2 source in a neighboring state is PSNH Schiller Station 
in Portsmouth, New Hampshire. The EPA has assessed potential 
SO2 impacts from Massachusetts sources on the New Hampshire 
area with SO2 sources near the Massachusetts border, 
specifically the Portsmouth, New Hampshire area and the Central New 
Hampshire nonattainment area, by examining monitoring and modeling 
information. These assessments are presented as follows for the Central 
New Hampshire nonattainment area and the Portsmouth, New Hampshire 
area.
    First, the EPA assessed information presented by Massachusetts 
regarding the State's impacts in the Central New Hampshire 
nonattainment area. Massachusetts reviewed potential SO2 
impacts on the Central New Hampshire area, which includes parts of 
Hillsborough, Merrimack, and Rockingham counties, and was designated as 
a nonattainment area for the 2010 SO2 NAAQS on August 5, 
2013. The nonattainment designation was related to a monitored 
violation of the NAAQS at a monitoring station in Pembroke, New 
Hampshire and caused primarily by SO2 emissions from nearby 
Merrimack Generating Station in Bow, New Hampshire.\8\ The Merrimack 
Generating Station facility installed an emissions control system in 
response to a New Hampshire requirement, and the New Hampshire 
Department of Environmental Services (NH DES) established stringent 
emissions limits and other conditions for the facility on September 1, 
2016. New Hampshire submitted an attainment plan for the Central New 
Hampshire area on January 31, 2017, which relied mainly on the 
emissions limits and other conditions established for the facility, and 
the EPA approved that plan on June 5, 2018.\9\ New Hampshire's 
attainment plan and demonstration relies on air dispersion modeling of 
the 1-hour critical emission value shown to be equivalent to the 
federally-enforceable 7-boiler operating day allowable emissions limit 
for the Merrimack Generating Station, in addition to monitored 
background concentrations. These measured background concentrations 
account for contributions from Massachusetts. The New Hampshire 
modeling analysis demonstrated that allowable emissions from Merrimack 
Generating Station, in addition to the background levels, will not 
cause a violation of the 1-hour SO2 NAAQS. The attainment 
plan did not require any reductions from Massachusetts sources, and 
relied solely on controls and limits at Merrimack Generating Station to 
address the nonattainment. Therefore, the EPA concludes that sources in 
Massachusetts do not contribute significantly to SO2 
nonattainment in the Central New Hampshire area.\10\
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    \8\ 40 CFR part 81 Air Quality Designations for the 2010 Sulfur 
Dioxide (SO2) Primary National Ambient Air Quality 
Standard (78 FR 47191, August 5, 2013).
    \9\ See the EPA's final action on the Central New Hampshire 
Nonattainment Area Plan for the 2010 SO2 NAAQS at 83 FR 
25922 (June 5, 2018).
    \10\ On July 31, 2019, the EPA published a proposal to formally 
redesignate the Central New Hampshire SO2 Nonattainment 
Area to attainment for the 2010 SO2 NAAQS (84 FR 37187).
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    Second, the EPA has assessed information, including both monitoring 
and modeling information, for the area around Portsmouth, New Hampshire 
during the third round of SO2 designations.\11\ For 
monitoring information, the EPA reviewed available monitoring data in 
the Portsmouth, New Hampshire area. There is one SO2 monitor 
(Site ID 33-015-0014--See Table 1) in the area, located 4 km southeast 
of PSNH Schiller Station. As shown, this monitor recorded a design 
value of 13 ppb from 2016-2018. This design value indicates that 
SO2 levels are low (17% of the NAAQS) in areas of 
Portsmouth. An additional monitor sited at Sawgrass Lane in Eliot, 
Maine (Site ID 23-031-0009), was located 1.1 miles to the northeast of 
PSNH Schiller Station and collected ambient SO2 data from 
October 24, 2014 to April 1, 2016. The maximum 1-hour SO2 
concentration observed from this monitor was 37.7 ppb on January 8, 
2015, when winds came from the direction of PSNH Schiller Station and 
the power plant was operating at near-maximum capacity.\12\ While the

[[Page 38903]]

Portsmouth SO2 monitor is not sited to determine maximum 
impacts from PSNH Schiller Station, the Sawgrass Lane monitor measured 
combined impacts from PSNH Schiller Station and background 
concentrations for the area that generally include contributions from 
sources emitting upwind in Massachusetts. Additionally, Massachusetts 
noted air quality modeling by the State of New Hampshire. New 
Hampshire's air quality modeling indicates that allowable emissions 
from PSNH Schiller Station combined with background levels that include 
contributions from sources emitting SO2 in Massachusetts 
will not cause a violation of the 2010 SO2 NAAQS.\13\ The 
EPA has previously evaluated that modeling and agrees that the modeling 
supports Massachusetts's conclusion. Therefore, the EPA concludes that 
sources in Massachusetts would not contribute significantly to 
SO2 nonattainment in the Portsmouth, New Hampshire area.
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    \11\ A full assessment of New Hampshire's modeling for the 
Portsmouth, New Hampshire area is provided in the technical support 
document for the EPA's intended Round 3 air quality designations for 
the 2010 SO2 NAAQS (82 FR 41903, September 5, 2017).
    \12\ The Sawgrass Lane monitor was sited in an area expected to 
experience peak SO2 impacts from PSNH Schiller Station 
based on modeling information submitted by the Town of Eliot. 
Additional background and results of the Sawgrass Lane monitoring 
study are described in the report, ``Review of 2014-2016 Eliot, 
Maine Air Quality Monitoring Study,'' EPA, the Maine Department of 
Environmental Protection, and NH DES (September 2016).
    \13\ See EPA's final action of New Hampshire's SIP revision at 
83 FR 64470 (December 17, 2018).
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    The EPA also reviewed sources in neighboring and downwind states 
emitting more than 100 tpy of SO2 and located within 50 km 
of the Massachusetts border (see Table 3). This is because elevated 
SO2 levels, to which an SO2 source in 
Massachusetts may contribute, are most likely to be found near such 
sources. Massachusetts based its analysis on 2015 SO2 
emissions, and the EPA has included updated 2017 emissions as part of 
the weight of evidence analysis. As shown in Table 3, the shortest 
distance between a source emitting at least 100 tpy SO2 in 
Massachusetts and one in another state is 82 km. Given the localized 
range of potential 1-hour SO2 impacts, this indicates that 
there are no additional locations in neighboring and downwind states 
that would warrant further investigation with respect to Massachusetts 
SO2 emission sources that might contribute to problems with 
attainment of the 2010 SO2 NAAQS.

   Table 3--Neighboring and Downwind State SO2 Sources Greater Than 100 tpy and Within 50 km of Massachusetts
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                                                                                   Distance to
                                                                                     nearest       Massachusetts
                                   2015 SO2        2017 SO2       Distance to     Massachusetts     source 2015
            Source                 emissions       emissions     Massachusetts     SO2 source        emissions
                                   (tons) *         (tons)       border  (km)   greater than 100      (tons)
                                                                                    tpy  (km)
----------------------------------------------------------------------------------------------------------------
Lafarge North America--Ravena            4,806              63              36  107 (Solutia                 523
 (Ravena, New York).                                                             Inc--Springfiel
                                                                                 d).
Monadnock Paper Mills Inc          [dagger] 80             101              36  88 (Wheelabrator             224
 (Bennington, New Hampshire).                                                    Millbury Inc--
                                                                                 Millbury).
Norlite Corp (Cohoes, New       [dagger][dagge              60              34  117 (Solutia                 523
 York).                                 r] 117                                   Inc--Springfiel
                                                                                 d).
Northeast Solite Corporation    [dagger][dagge             303              39  121 (Solutia                 523
 (Glasco, New York).                    r] 222                                   Inc--Springfiel
                                                                                 d).
PSNH--Merrimack Station (Bow,              636             144              49  90 (Mystic                   729
 New Hampshire).                                                                 Station--Everet
                                                                                 t).
PSNH--Newington Station                    294              41              25  82 (Mystic                   729
 (Newington, New Hampshire).                                                     Station--Everet
                                                                                 t).
PSNH--Schiller Station                     858             263              26  82 (Mystic                   729
 (Portsmouth, New Hampshire).                                                    Station--Everet
                                                                                 t).
----------------------------------------------------------------------------------------------------------------
* Data retrieved, unless otherwise noted, by the EPA from its Emissions Inventory System gateway, available at
  https://www.epa.gov/air-emissions-inventories/emissions-inventory-system-eis-gateway, on July 22, 2019 for
  2015 emissions as submitted by MassDEP, New York Department of Environmental Conservation (NYDEC), New
  Hampshire Department of Environmental Services (NHDES), and Connecticut Department of Energy and Environmental
  Protection.
[dagger] Emissions data reported by NHDES.
[dagger][dagger] Emissions data reported by NYDEC.

    The EPA also assessed previous modeling information available for 
the Lafarge North America--Ravena facility in Ravena, New York. This 
modeling information was available based on the technical support 
document for the EPA's intended Round 3 air quality designations for 
the 2010 SO2 NAAQS (82 FR 41903, September 5, 2017). The 
Lafarge North America--Ravena facility had its kiln replaced in 2016, 
resulting in considerably lower emissions than those emitted prior to 
the kiln replacement. The Lafarge North America--Ravena facility was 
modeled using new allowable emissions rather than previous actual 
emissions and the modeling indicated the area around the facility would 
not violate the NAAQS. New York's modeling, which the EPA found 
accurately characterized air quality in the area of analysis, included 
monitored background concentrations for the area. Based on this 
information, the EPA concludes that combined impacts from Lafarge North 
America--Ravena and background levels will not cause a violation of the 
NAAQS.
    Massachusetts asserted that because there are no large sources of 
SO2 emissions that significantly affect any neighboring 
state, and because monitored SO2 levels in Massachusetts and 
adjacent states are substantially below the 2010 SO2 NAAQS, 
sources in Massachusetts do not significantly contribute to 
nonattainment areas in any neighboring states. The EPA agrees with this 
conclusion.
    In conclusion, for interstate transport prong 1, the EPA reviewed 
ambient SO2 monitoring data and SO2 emission 
sources both within Massachusetts and in neighboring and downwind 
states. Based on this analysis, the EPA proposes to determine that 
Massachusetts will not significantly contribute to nonattainment of the 
2010 SO2 NAAQS in any other state, per the requirements of 
CAA section 110(a)(2)(D)(i)(I).

C. The EPA's Prong 2 Evaluation--Interference With Maintenance of the 
NAAQS

    The EPA has reviewed available information on SO2 air 
quality and emission trends to evaluate the Commonwealth's conclusion 
that Massachusetts will not interfere with maintenance of the 2010 
SO2 NAAQS in downwind states.
    The EPA interprets CAA section 110(a)(2)(D)(i)(I) prong 2 to 
require an

[[Page 38904]]

evaluation of the potential impact of a state's emissions on areas that 
are currently measuring clean data, but that may have issues 
maintaining that air quality, rather than only former nonattainment 
areas (and thus current maintenance areas). Therefore, in addition to 
the analysis presented by Massachusetts, the EPA has also reviewed 
additional information on SO2 air quality and emission 
trends to evaluate the Commonwealth's conclusion that Massachusetts 
will not interfere with maintenance of the 2010 SO2 NAAQS in 
downwind states. This evaluation builds on the analysis regarding 
significant contribution to nonattainment (prong 1). Specifically, 
because of the low monitored ambient concentrations of SO2 
in Massachusetts and neighboring and downwind states, the EPA is 
proposing to find that SO2 levels in neighboring states near 
the Massachusetts border do not indicate any inability to maintain the 
SO2 NAAQS that could be attributed in part to sources in 
Massachusetts.
    As shown in Table 1 in section III.B. of this notice, the EPA 
reviewed 2016-2018 SO2 design value concentrations at 
monitors with data sufficient to produce valid 1-hour SO2 
design values in Massachusetts and neighboring states. There are no 
violating monitored design values in Massachusetts or neighboring or 
downwind states.
    Table 4 shows emission trends for Massachusetts along with 
neighboring and downwind states (Connecticut, Maine, New Hampshire, New 
York, Rhode Island, and Vermont).

             Table 4--Statewide SO2 Data (tpy) for Massachusetts and Neighboring and Downwind States
----------------------------------------------------------------------------------------------------------------
                                                                                                  SO2 reduction,
              State                    2000            2005            2010            2017        2000-2017 (%)
 
----------------------------------------------------------------------------------------------------------------
Massachusetts...................         208,146         139,937          57,892          15,100              93
Connecticut.....................          60,309          34,638          16,319          11,379              81
Maine...........................          57,906          32,397          17,020          10,447              82
New Hampshire...................          68,768          63,634          35,716           6,401              91
New York........................         543,868         386,568         170,247          38,641              93
Rhode Island....................           8,976           7,356           4,416           3,399              62
Vermont.........................           9,438           7,038           3,659           1,512              84
----------------------------------------------------------------------------------------------------------------

    As shown in Table 4, the statewide SO2 emissions from 
Massachusetts and neighboring and downwind states have decreased 
substantially over time, per the EPA's review of emissions trends data 
for these states.\14\ From 2000 to 2017, total statewide SO2 
emissions decreased by the following proportions: Massachusetts (93% 
decrease), Connecticut (81% decrease), Maine (82% decrease), New 
Hampshire (91% decrease), New York (93% decrease), Rhode Island (62% 
decrease), and Vermont (84%). This trend of decreasing SO2 
emissions does not by itself demonstrate that areas in Massachusetts 
and neighboring states will not have issues maintaining the 2010 
SO2 NAAQS. However, as a piece of this weight of evidence 
analysis for prong 2, it provides further indication (when considered 
alongside low monitor values in neighboring states) that such 
maintenance issues are unlikely. This is because the geographic scope 
of these reductions and their large sizes strongly suggest that they 
are not transient effects from reversible causes, and thus these 
reductions suggest there is very low likelihood that a strong upward 
trend in emissions will occur that might cause areas presently in 
attainment to violate the NAAQS.
---------------------------------------------------------------------------

    \14\ Additional emissions trends data are available at: https://www.epa.gov/air-emissions-inventories/airpollutant-emissions-trends-data.
---------------------------------------------------------------------------

    As noted in Massachusetts's submission, sources of SO2 
emissions will be addressed by Massachusetts's SIP-approved 
SO2 control programs. These programs include the low sulfur 
fuel rule, emissions standards for power plants, SO2 limits 
on municipal waste combustors, and a statewide permitting program. The 
low sulfur fuel rule reduces the sulfur content of oil combusted in 
stationary sources and requires the use of low sulfur fuel for large 
stationary engines and turbines based on EPA requirements for diesel 
fuel.\15\ Massachusetts notes in the submission that sulfur emissions 
from stationary sources will continue to decrease over time due to 
MassDEP's fuel rule. The State's Emissions Standards for Power Plants 
regulation establishes a facility-wide rolling 12-month SO2 
emissions rate of 3.0 pounds per megawatt-hour and a monthly average 
emissions rate of 6.0 pounds per megawatt-hour.\16\ The State's 310 CMR 
7.08 regulations establish limits on municipal waste combustors and 
requires such facilities to establish emission control plans and places 
limits on SO2.\17\ MassDEP's statewide permitting program 
establishes a pre-construction Plan Approval for sources that require 
Best Available Control Technology for pollutants will be emitted, 
including SO2, and ensures that projects requiring Plan 
Approvals will limit SO2 emissions.\18\ These regulations 
will help ensure that sulfur emissions from stationary sources will 
continue to decrease over time, and that new or modified stationary 
sources in Massachusetts will not cause exceedances of the 
SO2 NAAQS in neighboring states.
---------------------------------------------------------------------------

    \15\ See the EPA's final action of the regional haze portions in 
Massachusetts's SIP, at 78 FR 57487 (September 21, 2013).
    \16\ Id.
    \17\ See the EPA's final action of the reasonably available 
control technology (RACT) of nitrous oxides in Massachusetts's SIP, 
at 64 FR 48095, September 13, 1999.
    \18\ See the EPA's final action of the Massachusetts ``U 
Restricted Emission Status'' regulation into the SIP, at 60 FR 
17226, April 5, 1995. Massachusetts has delegation of the Federal 
Prevention of Significant Deterioration program (See CFR 40 
52.1165).
---------------------------------------------------------------------------

    In conclusion, for interstate transport prong 2, the EPA reviewed 
additional information about emissions trends, Massachusetts 
regulations that limit SO2 sources, and the technical 
information considered for interstate transport prong 1. The EPA finds 
that the combination of low ambient concentrations of SO2 in 
Massachusetts and neighboring and downwind states, the distances 
between cross-state SO2 sources, the downward trend in 
SO2 emissions from Massachusetts and neighboring and 
downwind states, and Massachusetts regulations that limit 
SO2 sources indicate no interference with maintenance of the 
2010 SO2 NAAQS from Massachusetts. Accordingly, the EPA 
proposes to determine that Massachusetts SO2 emissions 
sources will not interfere with maintenance of the 2010 SO2 
NAAQS in any other state, per the requirements of CAA section 
110(a)(2)(D)(i)(I).

[[Page 38905]]

IV. Proposed Action

    The EPA is proposing to approve Massachusetts's February 9, 2018 
submission of the 2010 SO2 NAAQS as meeting the interstate 
transport requirements of CAA section 110(a)(2)(D)(i)(I). The EPA is 
soliciting public comments on the issues discussed in this notice or on 
other relevant matters. These comments will be considered before taking 
final action. Interested parties may participate in the Federal 
rulemaking procedure by submitting written comments to this proposed 
rule by following the instructions listed in the ADDRESSES section of 
this Federal Register.

V. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the Act and 
applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, the EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air Act. 
Accordingly, this proposed action merely approves state law as meeting 
Federal requirements and does not impose additional requirements beyond 
those imposed by state law. For that reason, this proposed action:
     Is not a significant regulatory action subject to review 
by the Office of Management and Budget under Executive Orders 12866 (58 
FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
     Is not expected to be an Executive Order 13771 regulatory 
action because this action is not significant under Executive Order 
12866;
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the Clean Air Act; and
     Does not provide EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using practicable and legally permissible methods, under 
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where the EPA or an Indian tribe 
has demonstrated that a tribe has jurisdiction. In those areas of 
Indian country, the rule does not have tribal implications and will not 
impose substantial direct costs on tribal governments or preempt tribal 
law as specified by Executive Order 13175 (65 FR 67249, November 9, 
2000).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Reporting and recordkeeping 
requirements, Sulfur oxides.

    Dated: August 5, 2019.
Deborah Szaro,
Acting Regional Administrator, EPA Region 1.
[FR Doc. 2019-17000 Filed 8-7-19; 8:45 am]
 BILLING CODE 6560-50-P


