## Response to Comments on Proposed Massachusetts Certifications of Infrastructure State Implementation Plans for the 2008 Ozone NAAQS, 2010 N02 

## NAAQS, and 2010 S02 

## NAAQS

On August 3, 2013, the Massachusetts Department ofEnvironmental Protection (MassDEP) issued a notice ofpublic hearing on three proposed Certifications in which MassDEP concludes that the existing Massachusetts State Implementation Plan (SIP) adequately meets the basic ("infrastructure") requirements of42 U

.S.C. § 7410(a)(l) and (2), Sections l lO(a)(l) and (2) of the Clean Air Act (CAA) , with respect to the: • National Ambient Air Quality Standards (NAAQS) for ozone promulgated by the U.S. Environmental Protection Agency (EPA) on March 12, 2008 (the 2008 ozone NAAQS) ; • NAAQS for nitrogen dioxide (N02) promulgated by EPA on January 22, 2010 (the 2010 N02 NAAQS); and • NAAQS for sulfur dioxide promulgated by EPA on June 2, 2010 (the 2010 S02 NAAQS)

. MassDEP held a public hearing on the proposed Infrastructure SIP Certifications (I-SIPs) on September 6, 2013 and accepted comments on the proposals through September 16, 2013. On September 13 , 2013, EPA issued its "Guidance on Infrastructure State Implementation Plan Elements und er Clean AirAct Sections JJO(a)(l) and l JO(a)(2) " (EPA's Guidance).
The following parties submitted comments on the proposed I-SIP Certifications: • EPA Region 1 commented on the proposed Ozone, N02 and S02 1-SIPs; • The Sierra Club commented on the proposed Ozone and S02 I-SIPs. 

## EPA Comments 1

EPA submitted the fo llowing comments concerning the Ozone I-SIP, the N02 I-SIP and the S02 I-SIP. 1. Comment: Prevention of Significant Deterioration (PSD): Since Massachusetts does not have a SIP-approved PSD program, the PSD elements in the proposed Infrastructure SIPs (1- SIPs) are not approvable (e.g., section l 10(a)(2) sub-elements (C), (D)(i)(ll) , and (J) as they relate to the state's PSD program, as well as (D)(ii) , which relates to interstate and international pollution abatement). However, a Federal Implementation Plan (FIP) is already in place to address this issue. Therefore, no further action is necessary at this time. Response: MassDEP agrees that no further action is required.

1 EPA's comments are reproduced verbatim.2

. Comment: 11 O(a)(2)(A) Emission limits and other control measures: The proposed I-SIPs state that the Commonwealth will submit a SIP revision including a new definition ofthe term "National Ambient Air Quality Standards (NAAQS). " This SIP revision will need to be submitted before EPA can approve the infrastructure SIPs. Response: MassDEP's regulation 310 CMR 7.00 , Definitions , uses the term National Ambient Air Quality Standards (NAAQS) but does not define the term or indicate to which version ofthe standards the regulations refer. In 2012, EPA commented on MassDEP's I-SIPs for the 1997 and 2006 fine particulate matter NAAQS stating that MassDEP must add a definition ofNAAQS to its regulations and the definition must include a calendar date to make clear to which NAAQS version MassDEP ' s regulations refer.
To address the 2012 EPA comment, in May 2013 , MassDEP proposed a revision to 310 CMR 7.00 to include a definition ofthe term "NAAQS" that includes a calendar date. This revision will apply to all ofthe pollutants for which EPA sets NAAQS

. MassDEP has held hearings on the proposed revision and intends to promulgate the revision to 310 CMR 7.00 as soon as possible and submit it to EPA for inclusion in the Massachusetts SIP.
3. Comment: 11 O(a)(2)(B) Ambient Air quality monitoring/data system: Massachusetts ' proposed I-SIPs includes a citation to 40 CFR 52.370, regarding a SIP-approved air quality monitoring plan. We believe the citation should instead be to 40 CFR 52 .11 20(c)(36)

. Response: MassDEP has corrected the citation in each ofthe final I-SIPs.
4. Comment: 11 O(a)(2)(C) Enforcement: The proposed I-SIPs reference three state statutes , as well as regulation 310 CMR 5.00 for this sub-element. The statutes and regulations that Massachusetts is relying on to meet the enforcement requirement should be submitted for incorporation into the SIP. Response: MassDEP submitted, with the I-SIPs, copies ofthe following statutes that demonstrate that it has adequate enforcement authority:

• M.G.L. c. 111 , s. 142A

- O, Pollution Control Laws, as amended in 2009 and 2010. • M.G.L. c. 111 , s. 2C

. Pollution violations; orders of department of environmental protection. • M.G.L. c. 21A, s. 16. Civil Administrative Penalties. MassDEP is not requesting that these statutes be incorporated in the Massachusetts SIP

. In conversations with EPA Region 1 staff subsequent to EPA's submitting this comment, Region 1 staff advised that a copy ofthe statutes should be submitted with the final I-SIPs but that incorporation ofthe statutes into the SIPs is not required. Furthermore, EPA ' s Guidance concerning this SIP element states (p

. 24) that "new" provisions should be submitted for incorporation, but does not require submission ofexisting statutes and regulations for incorporation

. These MassDEP enforcement-related statutes and regulations are not new and have been a part ofMassDEP ' s air quality program for many years.

25. Comment: 11 O(a)(2)(D)(ii) Interstate pollution abatement and international air pollution: Under this sub-element, as noted on pages 38 and 39 ofEPA's I-SIP guidance, we recommend that Massachusetts include the following two statements in each I-SIP:
"No source or sources within Massachusetts are the subject of an active finding under section 126 ofthe Clean Air Act with respect to the [2008 ozone, 2010 S02, or 2010 N02] standard

."

"There are no final findings under section 115 ofthe Clean Air Act against Massachusetts with respect to the [2008 ozone, 2010 S02, or 2010 N0 2] standard. " Response: MassDEP inserted the two recommended statements into each ofthe final I-SIPs.
6. Comment: 11 O(a)(2)(H) Future SIP revisions: The proposed I-SIPs list the Massachusetts General Statute M.G.L. c 111 , s. 142A-N that allows for future SIP revisions. As noted on page 51 ofEPA's Guidance:
"To demonstrate that the requirements under (H) are met, the best practice for an air agency submitting an infrastructure SIP would be to submit, for inclusion into the SIP (if not already part ofthe SIP) , the statutory or regulatory provisions that provide the air agency or official with the authority to perform the following actions along with a narrative explanation ofhow they meet the requirements ofthis element: (1) revise its section 110 plan from time to time as may be necessary to take into account revisions of such primary or secondary NAAQS or the availability of improved or more expeditious methods of attaining such standards; and (2) revise the plan in the event the Administrator finds the plan to be substantially inadequate to attain the NAAQS or otherwise meet all applicable CAA requirements. " p. 51 , EJ;>A ' s Guidance. Response: MassDEP notes that EPA's Guidance, at page 5 1, also states the following:

" Ifan air agency chooses not to include the relevant statute or regulation in its SIP, then the air agency should provide a reference or citation to the authority provisions, along with a narrative explanation ofhow the provisions meet the requirements ofthis element, as well as a copy ofthe relevant authority to accompany the SIP as required by 40 CFR 51.231

." As noted in the response to comment #4, MassDEP submitted a copy of. M.G.L. c. 111, s. 142A

- O, as amended in 2009 and 2010, with the I-SIP. The specific sections cited below demonstrate that MassDEP has authority to amend the Massachusetts SIP as needed. Section 142A: "The department ofenvironmental protection, referred to in this section and in sections one hundred and forty-two B through one hundred and forty-two M, inclusive, as the department may from time to time adopt regulations, pursuant to this section and sections one hundred and forty-two B through one hundred and forty-two M, inclusive, to prevent pollution or contamination ofthe atmosphere

."
Section 142D: "From time to time the department shall review the ambient air quality standards and plan for implementation, maintenance and attainment of such standards adopted pursuant to this section and, after public hearings, shall amend such standards and implementation plan so as 3to minimize the economic cost of such standards and plan for implementation, provided, however, that such standards shall not be less than the minimum federal standards ."
7. Comment: 11 O(a)(2)(J) Public Notification: The proposed 1-SIPs reference a statutory requirement that Mass DEP provide notice and public comment and hearing prior to adoption of regulations. However, this sub-element deals with the public notification ofpoor air quality

. (See page 54 ofEPA' s I-SIP guidance.) Therefore, EPA recommends that the DEP instead reference Massachusetts ' participation in AIRNOW and its activities to regularly notify the public ofexceedances of the air quality standards (e.g. , air quality web site, alerts , press releases , etc.) Response: MassDEP has revised its discussion ofthis requirement to reference Massachusetts ' participation in EPA' s AIRNOW program and MassDEP ' s daily air quality forecasts and alerts and air quality web site. 8. Comment: 11 O(a)(2)(J) Consultation with Government Officials: For this sub-element, the proposed 1-SIPs list three Massachusetts General Statutes (M

.G.L. c 21a, c. 111 and c. 30A) and an Executive Order and do not list any SIP-approved regulations that require consultation. EPA recommends that DEP consider referencing Section VII ofthe Massachusetts 1972 SIP which does require the DEP to consult with other government officials in its regulatory actions. Section II ofthe Massachusetts 1972 SIP may also be relevant. Alternatively, Massachusetts could submit the appropriate state statutes for incorporation into the SIP. Furthermore, as noted on page 53 ofEPA ' s Guidance:
"Under the requirements of40 CFR 51.2402

, the SIP would need to identify organizations that will participate in developing, implementing and enforcing the plan and the responsibilities of such organizations. The plan should also include any related agreements or memoranda ofunderstanding among the organizations. " Response: The final 1-SIPs references the 1972 Massachusetts Plan for the Implementation, Maintenance, and Enforcement ofNational Primary and Secondary Ambient Air Quality Standards (the 1972 SIP) , which documents the requirements for MassDEP to consult with other government officials. Section VII ofthe 1972 SIP, entitled " Intergovernmental and InterAgenc y Cooperation " provides that Massachusetts will cooperate with adjoining and other states to address interstate air quality control, citing NESCAUM (the New England Stafffor Coordinating Air Use Management) 3 as an example ofinterstate cooperation. Since the submission ofthe 1972 SIP, MassDEP has maintained active membership in NESCAUM, which has continued to be a forum for consultation with air program officials ofother states in the northeast. In addition , interstate consultation became a federal statutory requirement through the creation ofthe Ozone Transport Region (OTR) pursuant to the 1990 Clean Air Act

2 40 CFR § 51.240

- General plan requirements

. Each State implementation plan must identify organizations, by official title, that will participate in developing, implementing, and enforcing the plan and the responsibilities of such organizations

. The plan shall include any related agreements or memoranda ofunderstanding among the organizations

. 3 NESCAUM is now the Northeast States for Coordinated Air Use Management and includes the states ofNew York and New Jersey . 4Amendments. Massachu setts is within the OTR and actively participates in the Ozone Transport Commission, which coordinates interstate air quality planning among the OTR states. Section VII (c) ofthe 1972 SIP also discusses the existence of six air quality control regions within Massachusetts, and the role ofthe Bureau ofAir Quality Control (at that time within the Department ofPublic Health) in administering, overseeing and coordinating inter-district cooperation. The role ofmunicipally-operated air pollution control programs within the six air quality control regions in implementing the air program is discussed in detail in Section VII , Resources. Section VII (d) ofthe 1972 SIP lists the state statues that require the cooperation and/or assistance in the control of air pollution by other state agencies. Section II ofthe 1972 SIP, "LegalAuthority" lists the statutes that provide MassDEP with the legal authority to carry out the plan. The statutes cited also provide that cities or towns may apply to MassDEP to form air pollution control districts. The powers, duties , and rights of MassDEP in the exercise ofair pollution control in such districts are spelled out in the statutes referenced in the I-SIP. MassDEP submitted to EPA on September 1, 1977, a Memorandum ofUnderstanding signed by the Massachusetts air and transportation agencies related to Section 109(a)(2)(J) requirements concerning the integration ofair quality considerations into the transportation planning and development process. As noted in the proposed I-SIPs, Executive Order No. 145, adopted in 1978 , requires state agencies, including MassDEP, to provide notice to the Local Government Advisory Committee soliciting input on the impact ofproposed regulations on local government. MassDEP submitted a copy ofExecutive Order No. 145 with the final I-SIPs. The final I-SIPs note that MassDEP has the responsibility for overall coordination of SIP planning and is the lead compliance and enforcement agency related to all matters incorporated into SIPs. These responsibilities were outlined in a July 9, 1993 letter from Governor William F. Weld to EPA Region 1. The Jetter designates MassDEP as the lead agency for stationary and area sources and the lead for programs related to motor vehicle fuels, vehicle inspection and maintenance, and ridesharing. The letter designates the Executive Office ofTransportation and Construction (EOTC)4 as the lead agency in SIP planning for all transportation initiatives in consultation with Metropolitan Planning Organizations, which include representation of locallyelected officials through membership on transit authority advisory boards and regional planning commissions. The letter states that MassDEP must approve all actions incorporated into the SIP. For enforcement oftransportation initiatives, MassDEP may rely on other state and local agencies including the State Police, the Registry ofMotor Vehicles, the Massachusetts Highway Department, and local law enforcement and public health officials.
Massachusetts does not have a SIP-approved state transportation conformity rule. However, consistent with section 176 ofthe CAA and 40 CRF 93 relative to conformity determinations, including provisions for consultation as required by section l 76(c)(4) and 40 CFR 93.105 ,

4 The EOTC is now the Massachusetts Department ofTransportation. 5MassDEP and the Massachusetts Department ofTransportation consult with local, regional , and federal agencies to ensure that transportation plans, programs, projects, and federal actions are consistent with the SIP.
9. Comment: 110(a)(2)(J) Visibility Protection: Under this sub-element, the proposed I-SIPs refer back to the earlier Massachusetts chart entry for 11 O(a)(2)(C), but there is no discussion on visibility under element (C)

. However, as noted on page 55 ofEPA's Guidance:
"The EPA believes that there are no new visibility protection requirements under part C as a result of a revised NAAQS (National Ambient Air Quality Standard). Therefore, there are no newly applicable visibility protection obligations pursuant to Element J after the promulgation of a new or revised NAAQS. Air agencies do not need to address the visibility sub-element ofElement Jin an infrastructure SIP submission. " Therefore, we recommend that under the 

### (J) visibility protection sub-element, DEP delete the current reference to back to (C) and instead state that this element does not need to be addressed pursuant to EPA ' s Guidance. Response: MassDEP has revised this section as EPA recommends.
10. Comment: 110(a)(2)(M) Consultation and Participation by affected local entities: The proposed I-SIPs list Massachusetts General Statute M.G.L. c. 30A and an Executive Order and do not list any SIP-approved regulations that require consultation. EPA recommends that DEP consider referencing Section VII ofthe Massachusetts 1972 SIP which does require the DEP to consult with other government officials in its regulatory actions. Section II ofthe Massachusetts 1972 SIP may also be relevant. Alternatively, Massachusetts could submit the appropriate state statutes for incorporation into the SIP. Response: The final I-SIPs include references to the contents ofthe 1972 SIP that relate to this element. As noted in the response to comment #8 (110(a)(2)(J)

- Consultation with Government Officials) , the 1972 SIP includes provisions relating to consultation with local political subdivisions. Section VII (c) ofthe 1972 SIP discusses six air quality control regions within Massachusetts, and the role ofthe Bureau ofAir Quality Control (at that time within the Department ofPublic Health) in administering, overseeing and coordinating inter-district cooperation. The role ofmunicipally-operated air pollution control programs within the six air quality control regions in implementing the air program is discussed in detail in Section VII, Resources

. Section VII (d) ofthe 1972 SIP lists the state statues that require the cooperation and/or assistance in the control ofair pollution by other state agencies. Section II ofthe 1972 SIP, " LegalAuthority" lists the statutes that provide MassDEP with the legal authority to carry out the plan. The statutes cited also provide that cities or towns may apply to MassDEP to form air pollution control districts. The powers, duties , and rights ofthe department in the exercise ofair pollution control in such districts are spelled out in the statutes referenced in the I-SIP.

6

### •

As noted in the Response to comment #8 , MassDEP submitted with the final I-SIPs a copy of Executive Order No. 145 , which requires state agencies to provide notice to the Local Government Advisory Committee soliciting input on the impact ofproposed regulations on local governments. The final I-SIPs also include discussion ofMassDEP's policy related to consultation with local political subdivisions through the Massachusetts SIP Steering Committee, which was created pursuant to the 1990 Clean Air Amendments. The following constituencies are represented on the SIP Steering Committee: local and regional governmental entities, business and industry, and environmental groups and academia. The Committee provides a forum for consultation and participation by affected local entities in the development of SIPs and air quality regulations. Additionally, as a matter ofpolicy when adopting air regulations, MassDEP conducts stakeholder outreach, including meetings to elicit stakeholder feedback, before proposing regulations for formal public review and comment. Local entities affected by regulations or SIP revisions are provided opportunities to consult with MassDEP through the stakeholder outreach process. M.G.L. c. 30A, Administrative Procedures, provides that MassDEP must provide public notice in accordance with Chapter 30A prior to the adoption, amendment, or repeal of any regulation. Leaders ofpolitical subdivisions have the opportunity to review such notices and to participate in the public process required by Chapter 30A. MassDEP also must comply with EPA requirements related to public notice of SIP revisions , which puts local political subdivisions on notice ofchanges that may affect them

. 

## Sierra Club Comments 5


### Sierra Club comments concerning the Ozone I-SIP
1. Comment: The regulations cited in the proposed infrastructure SIP fail to ensure adequate compliance with the 2008 ozone NAAQS. Response: The Massachusetts SIP includes multiple regulations to control ozone precursors, which are cited in the I-SIP. These regulations ensure compliance with the 2008 ozone NAAQS as demonstrated by Massachusetts' state

-wide attainment designation, except for Duke's County, which has been designated as a marginal nonattainment area. 77 FR 30088, May 21 , 2012. The ozone concentrations in Duke's County leading to a marginal nonattainment designation are attributable to transported pollution from states that are upwind ofMassachusetts

. 2. Comment: The Ozone I-SIP must include provisions to ensure that ozone emissions will not cause or significantly contribute to nonattainment or interfere with maintenance ofthe Ozone NAAQS in another state.

5 Sierra Club 's comments are summarized in this document. 7Response: To address the contribution ofupwind states to ozone in downwind states, EPA promulgated the Cross-State Air Pollution Rule (CSAPR) in 2011 to replace EPA's 2005 Clean Air**Int~rstate** Rule (CAIR). In its CSAPR transport analysis, EPA found that Massachusetts does not significantly contribute to ozone nonattainment or interfere with maintenance in any other state. 76 FR 48213 , August 8, 2011. EPA 's CSAPR analysis is the latest contribution analysis available

. Note that in August 2012, the D.C. Circuit Court ofAppeals vacated CSAPR and left CAIR in place, but on April 29 , 20 14, the Supreme Court ofthe United States upheld CSAPR and remanded the case back to the D.C. Circuit Court ofAppeals. MassDEP continues to implement the MassCAIR program. Once EPA decides how it intends to proceed with CSAPR, MassDEP will submit a separate transport SIP to EPA to address this issue ifnecessary , once EPA has provided updated guidance.
3. Comment: The Ozone I-SIP should include measures to address significant sources of ozone precursors , such as electric generating units. Response: The Massachusetts Ozone SIP includes multiple regulations to control ozone precursors from stationary sources, including electric generating units. These regulations are cited in the I-SIP (for example, see page 7).
4. Comment: The Ozone I-SIP should include measures to address leaks from natural gas distribution pipelines. Methane is a major source ofozone precursors. Leaking gas pipelines create risks ofexplosions and increase costs to consumers . Response: The Massachusetts Ozone SIP includes multiple regulations to reduce emissions of volatile organic compounds (VOCs) , which contribute to the formation of ozone. 310 CMR 7

.00, Definitions , lists those compounds, including methane, that are excluded from the definition ofVOC. Methane is not a VOC so is not regulated as part ofthe Ozone SIP. 

### Sierra Club comments concerning the Ozone I-SIP and the S02 I-SIP
5. Comment: The proposed Ozone I-SIP and the proposed S02 I-SIP impermissibly fail to incorporate the respective revised NAAQS. Response: As noted in MassDEP ' s Response to EPA' s Comment # 1 above, MassDEP intends to promulgate a revision to 310 CMR 7

.00, Definitions , to add a definition ofNAAQS that addresses this issue.
6. Comment: The Ozone I-SIP and S02 I-SIP must protect visibility in other states and cannot rely on a Regional Haze Plan that has not been approved by EPA. Response: EPA approved the Massachusetts Regional Haze SIP effective October 21 , 2013. 78 Federal Register 57487 , September 19, 2013.

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### Sierra Club comments concerning the S02 I-SIP
7. Comment: The Clean Air Act, EPA's regulations and EPA's interpretations thereof , and court opinions, require that 1-SIPs must have emission limits adequate to prevent AAQS violations in areas not designated nonattainment. Response: As stated in EPA's Guidance, pursuant to CAA Section 110(a)(2) states are required to develop and maintain an air quality management program that meets various basic structural requirements including "enforceable emission limitations. " EPA has not interpreted the requirement for " enforceable emission limitations" to include single-source specific emission limitations in an infrastructure SIP. Rather, a state must demonstrate that it has in place a regulatory framework that requires the imposition ofenforceable emission limitations to insure the NAAQS can be attained and maintained. Consistent with EPA 's Guidance, MassDEP's S02 I-SIP demonstrates that it has the regulatory framework allowing it to impose and enforce such emission limits. (See Response to Comment # 10 below.)
8. Comment: The Sierra Club encourages MassDEP to expeditiously complete its 310 CMR7.02(7) compliance demonstration processes for Brayton Point and Mount Tom and to impose appropriate modeling-informed short-term emission limits for both plants. Response: MassDEP is working to complete its 310 CMR 7.02(7) review process related to S02 emissions and emission limits for these two facilities as quickly as possible. 9. Comment: MassDEP should coordinate the timing offinalizing the S02 I-SIP so that it incorporates the modeling-informed short-term emissions limits for Brayton Point and Mount Tom into the SIP. Response: As noted above in its Response to Sierra Club comment #7, EPA has not interpreted the requirement for "enforceable emission limitations " to include single-source specific emission limitations in an infrastructure SIP. Rather, a state must demonstrate that it has in place a regulatory framework that requires the imposition ofenforceable emission limitations to insure the NAAQS can be attained and maintained. Consistent with EPA's Guidance, MassDEP's S02 I-SIP demonstrates that it has the regulatory framework allowing it to impose and enforce such emission limits

. 10. Comment: Should MassDEP decline to delay finalization ofthe I-SIP , MassDEP should include in the SIP a provision clarifying the requirement ofenforceable NAAQS-protective emission limits for sources calculated to cause exceedances ofthe standard. Response: MassDEP regulations that are already part ofthe Massachusetts SIP include provisions to ensure that facilities do not cause NAAQS violations. 310 CMR 7.02, Plan Approval and Emission Limitations, provides procedures and standards for issuing approvals in Massachusetts and establishing emission limitations and conditions for facilities and emission units

. 310 CMR 7.02 generally requires a plan approval (permit) prior to any construction, substantial reconstruction, alteration, or subsequent operation of a facility that may emit contaminants to the ambient air. It also allows MassDEP to address a condition ofair pollution
9caused by a facility. The following provisions of 310 CMR 7.02 address the issue ofNAAQS compliance:
310 CMR 7.02(3)U) , General Requirements for Plan Approval , provides that MassDEP will issue a plan approval for a stationary source only ifthe emissions from a facility do not result in air quality exceeding either the Massachusetts or National Ambient Air Quality Standards.
310 CMR 7.02(5)(a) 10, Comprehensive Plan Application, provides that facilities that do not trigger the general approval requirements of 310 CMR 7.02(3)U), are required to apply for an approval ifMassDEP determines that the facility has the potential to cause or contribute to a condition of air pollution.
310 CMR 7.02(7) , Mitigation of A ir Pollution, provides that when MassDEP determines that a facility has the likelihood ofcausing or contributing to a condition ofair pollution, MassDEP may require that the facility submit information to allow MassDEP to determine the adequacy of existing air pollution control technology at a facility to prevent a condition ofair pollution.
These provisions of 310 CMR 7

.02 ensure that stationary emissions sources will be subject to enforceable NAAQS-protective emissions limits. MassDEP's current re-assessment of S02 emissions from the Brayton Point and Mt Tom facilities exemplify the adequacy ofMassDEP's existing regulatory infrastructure. Pursuant to 310 CMR 7.02, MassDEP is conducting a comprehensive review ofthese facility emissions and measures to ensure NAAQS compliance

. 11. Comment: The S02 I-SIP must include provisions to ensure that S02 emissions will not cause or significantly contribute to nonattainment or interfere with maintenance ofthe S02 NAAQS in another state. Response: According to EPA ' s Guidance, an I-SIP must demonstrate that a regulatory framework is in place to ensure that emissions within the state do not interfere with downwind maintenance and attainment. As noted in the response to comment #7, MassDEP ' s S02 I-SIP demonstrates that it has the regulatory framework to ensure S02 emissions will not cause or significantly contribute to nonattainment or interfere with maintenance ofthe S02 NAAQS in another state

. In addition, until EPA completes final designations for areas downwind of Massachusetts it is premature to address the possible contribution ofMassachusetts sources to downwind S02 maintenance or attainment issues. 6

6 In 2011 , New Hampshire recommended to EPA that a portion ofcentral NH be designated as an S02 nonattainment area. New Hampshire ' s technical support for its nonattainment recommendation does not reflect any contribution to nonattainment from Massachusetts sources. http://des. nh. gov/organization/divi sion s/air/do/sip/documents/so2-nh-designation-request.pdf 10 

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