UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street

Philadelphia, Pennsylvania 19103

DATE: September 16, 2013

SUBJECT: Technical Support Document for the Delaware State Implementation Plan for the 

Infrastructure Requirements for the 2010 Sulfur Dioxide National Ambient Air 

Quality Standards

/s/

FROM: Rose Quinto, Environmental Engineer

Office of Air Program Planning

TO: File

/s/

THRU: Cristina Fernandez, Associate Director

Office of Air Program Planning 

A. INTRODUCTION

The Environmental Protection Agency (EPA) is taking action on a submittal made by the State of 

Delaware to meet the Clean Air Act (CAA) section 110(a)(2) infrastructure requirements for the

2010 sulfur dioxide (SO2) national ambient air quality standards (NAAQS).

B. BACKGROUND

On June 22, 2010 (75 FR 35520), EPA promulgated a revised NAAQS for the 1-hour primary

SO2 at a level of 75 parts per billion (ppb), based on a 3-year average of the annual 99th percentile 

of 1-hour daily maximum concentrations.

Section 110(a) of the CAA requires states to submit state implementation plans (SIPs) that 

provide for the implementation, maintenance, and enforcement of new or revised NAAQS within 

three years following the promulgation of such NAAQS. Section 110(a) of the CAA imposes the 

obligation upon states to make a SIP submission to EPA for a new or revised NAAQS. For the 

2010 SO2 NAAQS, states typically have met many of the basic program elements required in 

section 110(a)(2) of the CAA through earlier SIP submissions in connection with previous SO2

standards. Section 110(a)(2) of the CAA lists specific elements that states must meet or continue 

to meet in these SIP submissions. The requirements include SIP infrastructure elements such as

requirements for modeling, monitoring, and emissions inventories that are designed to assure 

attainment and maintenance of the NAAQS. 
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C. EPA REQUIREMENTS

As discussed above, for the 2010 SO2 NAAQS, states must provide SIP submissions, or provide 

certification that the existing SIP contains provisions addressing relevant infrastructure SIP 

elements from sections 110(a)(2)(A) through (M) of the CAA. 

D. STATE’S SUBMITTAL

On May 29, 2013, Delaware provided a submittal to satisfy the requirements of section 110(a)(2) 

of the CAA for the 2010 SO2 NAAQS. This submittal addressed the following infrastructure 

elements that EPA is proposing to approve: Section 110(a)(2)(A), (B), (C), (D)(i)(II), (D)(ii), 

(E), (F), (G), (H), (J), (K), (L), and (M) of the CAA. The submittal also addressed section 

110(a)(2)(D)(i)(I) but EPA will take separate action on that part of the Delaware submittal. This 

submittal did not include element (I) which pertains to the nonattainment requirements of part D, 

Title I of the CAA, since this element is not required to be submitted by the 3-year submission 

deadline of CAA section 110(a)(1), and will be addressed in a separate process.

E. EVALUATION OF STATE SUBMITTAL

1. Section 110(a)(2)(A)

EPA has determined that Delaware has established laws and regulations applicable to the 2010 

SO2 NAAQS that include enforceable emissions limitations and other control measures, means 

or techniques, as well as schedules and timetables for compliance to meet the applicable 

requirements of the CAA. The following enforceable emission limitations and schedules are 

contained in Delaware’s approved SIP: 7 DE Admin. Codes 1101 (Definitions and 

Administrative Principles), 1108 (SO2 Emissions from Fuel Burning Equipment), 1109

(Emissions of Sulfur Compounds from Industrial Operations), 1110 (Control of SO2 EmissionsKent and Sussex Counties), 1127 (Stack Heights), 1144 (Control of Stationary Generator 

Emissions), 1145 (Excessive Idling of Heavy Duty Vehicles), and 1146 (Electric Generating Unit 

Multi-Pollutant Regulation). These regulations are identified as part of the Delaware SIP at 40 

CFR 52.420(c). 

At present, statutory authority is set out in Title 7 “Conservation” of the Delaware Code, Chapter 

60—Delaware’s comprehensive water and air resources conservation law. Legislative authority

giving the Secretary of the Delaware Department of Natural Resources and Environmental 

Control (DNREC) the authority to promulgate regulations is codified at 7 Del. C., Chapter 60. 

This authority is applicable to the 2010 SO2 NAAQS.

In this rulemaking action, EPA is not proposing to approve or disapprove any existing Delaware

provisions with regard to excess emissions during startup, shutdown, and malfunction (SSM) of 
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operations at a facility. EPA believes that a number of states have SSM provisions which are 

contrary to the CAA and existing EPA guidance (August 11, 1999, Steven Herman and Robert 

Perciasepe Guidance Memorandum, “State Implementation Plans: Policy Regarding Excess 

Emissions During Malfunctions, Startup, and Shutdown”), and EPA is addressing such state 

regulations in a separate rulemaking action. See 78 FR 12460, February 22, 2013. In the 

meantime, EPA encourages any state having a deficient SSM provision to take steps to correct it 

as soon as possible. 

Also in this action, EPA is not proposing to approve or disapprove any existing Delaware rules 

with regard to director’s discretion or variance provisions. EPA believes that a number of states 

have such provisions which are contrary to the CAA and existing EPA guidance (see 52 FR 

45109, November 1987), and EPA is taking separate rulemaking action to address such state 

regulations. See 78 FR 12460. In that proposed rulemaking, EPA identified specific Delaware 

regulations in which state officials are provided unbounded discretion to set alternative emission 

limits during periods of start-up and shutdown of equipment through a permitting process that 

does not entail subsequent approval of the alternative emission limits through a SIP revision. 

EPA has proposed to find that this process constitutes an impermissible director’s discretion 

provision with the potential to allow impermissible discretionary exemptions from SIP emission 

limits. See 78 FR 12495-12496. In the meantime, EPA encourages any state having director’s 

discretion or variance provisions which are contrary to the CAA and EPA guidance to take steps 

to correct the deficiency as soon as possible.

Based upon EPA’s review of the submittal, EPA is proposing to determine that the State has met 

its obligations pursuant to 110(a)(2)(A). 

2. Section 110(a)(2)(B)

7 DE Admin. Code 1103 – “Ambient Air Quality Standards” and 7 DE Admin. Code 1117 –

“Source Monitoring, Record Keeping and Reporting” provide for the establishment and 

operation of procedures necessary to monitor, compile, and analyze data related to ambient air 

quality. These regulations are included in Delaware’s approved SIP listed in 40 CFR 52.420(c).

Delaware has established and currently operates appropriate devices, methods, systems, and 

procedures necessary to monitor, compile, and analyze data on ambient air quality, and upon 

request, makes such data available to the Administrator. 

Delaware maintains and operates a multi-station network of ambient monitors throughout the 

State to measure ambient air quality levels within Delaware for comparison to each NAAQS as 

required by 40 CFR part 58. Delaware measures and reports SO2 concentrations from 

monitoring sites located in Wilmington near MLK Boulevard, Delaware City, Bellefonte,

Summit Bridge, and Lewis.
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All data is measured using EPA approved methods as either Reference or Equivalent monitors. 

All monitors are subjected to the quality assurance requirements of 40 CFR part 58, Appendix A, 

and all samplers are located at sites that have met the minimum siting requirements of 40 CFR 

part 58, Appendix E. The data is submitted to EPA’s Air Quality System (AQS) in a timely

manner in accordance with the schedule prescribed by EPA in 40 CFR part 58.

In order to keep EPA informed of changes to the sampling network, DNREC provides EPA 

Region III with prior notification of any planned changes to the network. As needed, details of 

these changes and anticipated approvals of the changes are communicated to EPA. On an annual 

basis, Delaware sends EPA a monitoring network plan as required by 40 CFR part 58, section 10

(Annual Monitoring Network Plan and Periodic Network Assessment). EPA approved 

Delaware’s 2012 Annual Air Quality Monitoring Network Design Plan on February 21, 2013. 

This plan contains all required information including site and monitor description, analysis 

methods, operating schedule, monitoring objectives and scale of representativeness, as well as 

information on any planned changes. DNREC submits data to the AQS system, in a timely

manner, pursuant to the schedule prescribed by EPA in 40 CFR part 58. Other requirements of 

the 2010 SO2 NAAQS include operational SO2 air quality monitoring network that was in place 

on January 1, 2013. Delaware has the appropriate number and location of SO2 monitors in New 

Castle and Sussex Counties. All monitors were operational as of January 1, 2013. 

Based upon EPA’s review of the submittal, EPA is proposing to determine that the State has met 

its obligations pursuant to 110(a)(2)(B). 

3. Section 110(a)(2)(C)

Delaware has established and currently operates a program to provide for the enforcement of the 

enforceable emission limitations and other control measures (including the measures identified 

for section 110(a)(2)(A) above), means, or techniques, as well as schedules and time tables for 

compliance, as may be necessary or appropriate, to meet the applicable requirements of the CAA 

and to regulate modification and construction of any stationary source within areas covered by its 

SIP as necessary to assure the NAAQS are achieved. Aspects of Delaware’s program for 

enforcement are found in those SIP-approved provisions of 7 DE Admin. Codes 1102 and 1125. 

At present, Delaware, as part of its Division of Air Quality function, exercises its programmatic 

authority to utilize the enforcement powers set out in 7 Del. C. section 6005 entitled, 

“Enforcement; civil and administrative penalties; expenses,” 7 Del. C., section 6013 entitled 

“Criminal penalties,” and 7 Del. C. section 6018 entitled “Cease and desist order.” 

Delaware implements its Construction and Operation Permit Program requirements under 7 DE 

Admin. Codes 1102 and 1125. These existing permitting programs which are part of the 

Federally-approved SIP ensure that the construction and modification of both major and minor 

stationary sources do not cause or contribute to a violation of the SO2 NAAQS.
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SIP approved 7 DE Admin. Code 1102 provides for the evaluation and necessary regulation of 

any stationary source that emits equal to or greater than 0.2 pounds of any air contaminant, 

including SO2, in any one day.

SIP approved 7 DE Admin. Code 1125 governs preconstruction review and permitting of any

new or modified major stationary source of air pollutants as required in Part C of Title I of the 

CAA. 

Based upon EPA’s review of the submittal, EPA is proposing to determine that the State has met 

its obligations pursuant to 110(a)(2)(C). 

 

4. Section 110(a)(2)(D)

Section 110(a)(2)(D)(i)(I)

In accordance with the decision of the U.S. Court of Appeals for the District of Columbia (D.C. 

Circuit Court), EPA at this time is not treating the 110(a)(2)(D)(i)(I) SIP submission from 

Delaware as a required SIP submission. See EME Homer City Generation, LP v. EPA, 696 F.3d 

7 (D.C. Cir. 2012), cer. granted, 2013 U.S. App. LEXIS 48101 (2013). On June 24, 2013, the 

Supreme Court granted the petitions of the United States and others and agreed to review this 

D.C. Circuit Court decision. However, at this time the D.C. Circuit Court decision remains in 

place and unless it is reversed or otherwise modified by the Supreme Court, states are not 

required to submit 110(a)(2)(D)(i)(I) SIP revisions until EPA has quantified their obligations 

under that section. Regardless of whether a particular SIP submission is considered to be 

“required,” section 110(k)(2) of the CAA requires EPA to act on the submission. Delaware’s 

May 29, 2013 infrastructure SIP submission for the 2010 SO2 NAAQS included information 

related to section 110(a)(2)(D)(i)(I). EPA will address this portion of Delaware’s submittal in a 

separate action.

Section 110(a)(2)(D)(i)(II)

For all areas of Delaware, a SIP- approved PSD program (Section 3.0 of 7 DE Admin. Code 

1125) is in place. See 40 CFR 52.420(c). See additional discussion under 110(a)(2)(C). Based 

upon EPA’s review of the submittal, EPA is proposing to determine that Delaware has met its 

obligations pursuant to 110(a)(2)(D)(i)(II) for the permit program to meet Part C of Title I of the 

CAA. EPA notes that the Delaware SIP also includes Delaware’s permit program to meet 

requirements in Part D of Title I of the CAA (applicable in nonattainment areas) for construction 

or modification of major stationary sources. See 7 DE Admin. Code 1125, Section 2.0. 
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Prong 4 of section 110(a)(2)(D)(i)(II) requires that SIPs include provisions prohibiting any source 

or other type of emissions activity in one state from interfering with measures to protect visibility

required to be included in another state’s SIP. Delaware’s regional haze SIP was approved on 

July 19, 2011 (76 FR 42557) and prohibits emission sources in Delaware from emitting air 

pollutants which would interfere with measures that protect visibility in other states. 

Based upon EPA’s review of the submittal, EPA is proposing to determine that the State has met 

its obligations pursuant to 110(a)(2)(D)(i)(II). 

Section 110(a)(2)(D)(ii) 

The Delaware SIP has adequate provisions to insure compliance with applicable requirements of 

sections 126 and 115 of the CAA. Delaware has a SIP approved PSD program (7 DE Admin 

Code 1125 – October 2, 2012, 77 FR 60053). In addition, there are no sources within Delaware 

that are subject to a finding under section 126 of the CAA with respect to the SO2 NAAQS. 

Also, there are no findings under section 115 of the CAA against Delaware with respect to the 

SO2 NAAQS. 

Based upon EPA’s review of the submittal, EPA is proposing to determine that the State has met 

its obligations pursuant to 110(a)(2)(D)(ii). 

5. Section 110(a)(2)(E)

For section 110(a)(2)(E)(i), Delaware has adequate authority under state law pursuant to

7 Del. C. Chapter 60 to carry out its SIP obligations with respect to the 2010 SO2 NAAQS. 

DNREC will continue to have, through the State of Delaware General Fund and through the Title 

V fee program, funding to carry out its SIP obligations. Furthermore, Delaware’s funding 

sources are sufficient to provide adequate personnel for those purposes. 

At present, Delaware also states that it fulfills this obligation by virtue of having adequate 

personnel and funding through the CAA section 105 grant process (Federal grant funds), the 

State of Delaware general fund (state tax revenues), and appropriated special funds collected by

the State of Delaware from application fees, permit fees, renewal fees, and civil or administrative 

penalties or fines under 7 Del. C. Chapter 60. DNREC’s Division of Air Quality is responsible 

for developing, implementing and enforcing the SIP. 

Delaware complies with the requirements of section 110(a)(2)(E)(ii) through compliance with the 

applicable requirements of 29 Del C., Chapter 58, “Laws Regulating the Conduct of Officers and 

Employees of the State,” which EPA approved as a SIP revision on April 17, 2013 (78 FR 

22785).
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The requirements of section 110(a)(2)(E)(iii) are not applicable to Delaware because Delaware 

does not rely on localities for specific SIP implementation.

Based upon EPA’s review of the submittal, EPA is proposing to determine that Delaware has met 

its obligations pursuant to 110(a)(2)(E). 

6. Section 110(a)(2)(F)

Specific monitoring and emissions reporting requirements are found throughout the State of 

Delaware’s regulations governing the control of air pollution, including 7 DE Admin. Codes 

1103 and 1117. These regulations are included in Delaware’s approved SIP and are listed in 40 

CFR 52.420(c).

Delaware’s SIP requires that owners or operators of stationary sources monitor and submit 

periodic reports on the nature and amounts of SO2 emissions and emissions related-data from 

sources. The information submitted to DNREC is available to the public at reasonable times for 

public inspection pursuant to Delaware law. Delaware’s SIP submittal stated that it will continue 

to require reporting of emissions. Delaware’s regulatory authorities include the ability for 

Delaware to require the installation, maintenance and replacement of equipment, where 

appropriate. 

Except as specifically exempted by the Delaware Freedom of Information Act, 29 Del. C.

Chapter 100, Delaware makes all records, reports or information obtained by DNREC or referred 

to at public hearings available to the public pursuant to the provisions of the Delaware Freedom 

of Information Act, 29 Del. C. Chapter 100.

Other aspects of Delaware’s program for requiring installation and maintenance of monitoring 

equipment, and periodic emissions reporting, are found in the source monitoring, source testing 

and test methods, and recordkeeping and reporting provisions of 7 DE Admin. Codes 1108,

1109, 1110, 1127, 1144, 1145, 1146 and others in the approved Delaware SIP, which is

identified at 40 CFR 52.420(c). 

Based upon EPA’s review of the submittal, EPA is proposing to determine that the State has met 

its obligations pursuant to 110(a)(2)(F). 

7. Section 110(a)(2)(G)

Delaware has authority comparable to that in section 303 of the CAA and adequate contingency

plans to implement such authority. 
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At present, 7 Del. C. section 6003(a)(1) requires a permit from the Secretary prior to discharging 

any air contaminant. 7 Del. C. section 6002(2) defines air contaminant essentially as any

substance other than uncombined water. 7 Del. C. section 6005 allows the Secretary to seek a 

preliminary or permanent injunction or temporary restraining order for discharge of an air 

contaminant without a permit authorization, and to issue a cease and desist order for violations 

(7 Del. C. section 6018). Therefore, if any discharge of an air contaminant, including SO2, would 

cause imminent and substantial endangerment to the health, safety and welfare of the people of 

the State of Delaware or the environment, the Secretary may seek an injunction or temporary

restraining order to halt the violation.

Delaware’s SIP contains an emergency episode plan found in 7 DE Admin. Code 1115, Air 

Pollution Alert and Emergency Plan, that is currently approved in the SIP and identified at 40 

CFR 52.420(c). 

Based upon EPA’s review of the submittal, EPA is proposing to determine that the State has met 

its obligations pursuant to 110(a)(2)(G). 

8. Section 110(a)(2)(H)

Through its SIP submission, Delaware has demonstrated that it has adequate authority under the 

Delaware Code, Chapter 60, Title 7 “Conservation” to revise the SIP. The submission also 

provides EPA with adequate assurances that Delaware will review and revise its SIP from time to 

time as may be necessary to take account of revisions of such primary or secondary NAAQS or 

the availability of improved or more expeditious methods of attaining such standards, whenever 

the Administrator finds, on the basis of information available to the Administrator, that the plan 

is substantially inadequate to attain the NAAQS which Delaware implements, or to otherwise 

comply with any additional requirements established under the CAA.

Based upon EPA’s review of the submittal, EPA is proposing to determine that the State has met 

its obligations pursuant to 110(a)(2)(H). 

9. Section 110(a)(2)(J)

Section 121 (relating to consultation). 7 DE Admin. Code 1132, Transportation Conformity of 

the State of Delaware Governing the Control of Air Pollution, provides a legal platform for the 

various consultation procedures that have been developed between DNREC, the Delaware 

Department of Transportation (DELDOT), and the Metropolitan Planning Organizations 

(MPOs). The MPOs provide the forum for consultation with local governments. Delaware’s 

MPOs are: WILMAPCO, Kent County MPO, and the Salisbury-Wicomoco MPO. Regional 

planning organizations provide the forum for inter-state consultations. 7 DE Admin. Code 1132 

is included in the Delaware SIP. Additionally, consultations with Federal Land Managers are 
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always ongoing in accordance with EPA rules (such as in the federal regional haze regulations). 

Section 127 (relating to public notification). All SIP revisions and new/amended regulations 

undergo public notice and hearing, pursuant to 7 Del. C. Chapters 29 and 60, which provides for 

publication in the newspapers and in the Delaware Register, and allow for comment by both the 

public and local political subdivisions. The public notice and hearing process also fulfills the 

section 121 consultation process. Approved regulations in the Delaware SIP specify the 

organizations responsible for implementing and enforcing the plans. In addition, DNREC makes

real time and historical air quality information available on its web site. 

PSD requirements necessary to implement the 2010 SO2 NAAQS are SIP approved and 

implemented through the requirements of 7 DE Admin. Code 1125, Preconstruction Review.

The latest Delaware PSD SIP was approved on October 2, 2012 (77 FR 60053).

With regard to visibility protection, there are no new applicable visibility protection obligations 

under section 110(a)(2)(J) as a result of the 2010 SO2 NAAQS. Delaware is complying with, and 

will continue to comply with the visibility protection and regional haze program requirements 

under part C of the CAA. EPA approved the Delaware regional haze SIP on July 19, 2011 

(76 FR 42557).

Based upon EPA’s review of the submittal, EPA is proposing to determine that the State has met 

its obligations pursuant to 110(a)(2)(J). 

10. Section 110(a)(2)(K)

As discussed in Delaware’s May 29, 2013 SIP submittal, Delaware has the authority and 

technical capability to conduct air quality modeling in order to assess the effect on ambient air 

quality relevant pollutant emissions and will continue to perform modeling. Delaware has a SIP 

approved PSD program (7 DE Admin Code 1125). Delaware will continue to submit to EPA the 

air quality modeling data as part of Delaware’s relevant SIP submissions, permit actions, and 

through Federal grant commitments or in other ways that EPA may request.

Based upon EPA’s review of the submittal and the Delaware SIP, EPA is proposing to determine 

that the State has met its obligations pursuant to 110(a)(2)(K). EPA is proposing to determine 

that Delaware has the authority and technical capability to conduct air quality modeling in order 

to assess the effect on ambient air quality of relevant pollutant emissions.

11. Section 110(a)(2)(L)

Delaware has a fully approved Title V operating permit program. See paragraphs (b) and (c) 

under “Delaware” in Appendix A to 40 CFR part 70—Approval Status of State and Local 
10

Operating Permits Programs.

Additionally, Delaware’s submission adequately addresses this requirement by explaining that 

consistent with Delaware law, Delaware will continue to require the owner or operator of each 

major stationary source to pay to the permitting authority, as a condition of any permit required

under the CAA, a fee sufficient to cover (i) the reasonable costs of reviewing and acting upon 

any application for such a permit, and (ii) if the owner or operator receives a permit for such 

source, the reasonable costs of implementing and enforcing the terms and conditions of any such 

permit (not including any court costs or other costs associated with any enforcement action), until 

such fee requirement is superseded with respect to such sources by the Administrator’s approval 

of a fee program under Title V pursuant to Delaware law. Delaware currently fulfills this under 

the enabling authority of 7 Del. C., sections 6095 to 6099, and fee legislation that currently is 

renewed every three years. 

Based upon EPA’s review of the submittal, EPA is proposing to determine that the State has met 

its obligations pursuant to 110(a)(2)(L). 

12. Section 110(a)(2)(M)

In the May 29, 2013 SO2 infrastructure SIP submittal, Delaware stated it will continue to provide 

for consultation and participation by local political subdivisions affected by the SIP pursuant to 

the public notice laws found in 7 Del. C., sections 6006 and 6010, and 29 Del. C. Chapters 

10003, 10004, and 10115, as applicable. Furthermore, Delaware stated all Delaware SIP 

revisions undergo public notice and hearing which has allowed for comment by the public which 

includes local political subdivisions. The public notice and hearing processes fulfill the 

requirements for consultation with local political subdivisions affected by the SIP.

Based upon EPA’s review of the submittal, EPA is proposing to determine that the State has met 

its obligations pursuant to 110(a)(2)(M). 

F. CONCLUSIONS AND RECOMMENDED AGENCY ACTION

EPA’s analysis of Delaware’s infrastructure submittal and the Delaware SIP for the 2010 SO2

NAAQS concludes that Delaware meets the requirements of sections 110(a)(2)(A), (B), (C),

(D)(i)(II), (D)(ii), (E), (F), (G), (H), (J), (K), (L), and (M) as identified above. EPA will take 

separate action on Delaware’s submittal for section 110(a)(2)(D)(i)(I). It is recommended that a 

notice of proposed rulemaking be prepared approving Delaware’s infrastructure submittal for the 

2010 SO2 NAAQS with the exception of the portion addressing section 110(a)(2)(D)(i)(I).