June 18, 2015

VIA ELECTRONIC MAIL

George (Tad) Aburn, Director

Air & Radiation Management Admin.

Maryland Department of the Environment

1800 Washington Blvd.

Baltimore, MD 21230

Email: george.aburn@maryland.gov

RE: Implementation of Sulfur Dioxide Consent Decree from Sierra Club v. 

McCarthy in Maryland

Dear Mr. Aburn:

On behalf of the Sierra Club I write to urge the Department to move forward with its 

stalled sulfur dioxide (SO2) regulations for coal-fired power plants in order to avoid 

nonattainment designations in Maryland, which would be required under the recent consent 

decree in Sierra Club v. McCarthy1if these regulations are not expeditiously finalized and 

adopted. To aid in this process, as an exhibit to this letter, I am providing the Department with 

updated steady state and time series modeling for SO2 emissions from the C.P. Crane, H.A. 

Wagner and Brandon Shores plants conducted by Wingra Engineering in adherence with EPA’s 

most current modeling guidance using the most current versions of U.S. EPA’s AERMOD

modeling software.2 The attached modeling results confirm that, absent enforceable regulatory 

action by the Department to address actual and allowable short-term emissions from these

facilities, Maryland would be required to recommend a nonattainment designation to the U.S. 

Environmental Protection Agency for the area surrounding these plants. In order to avoid this 

nonattainment designation, the Sierra Club urges the Department to expeditiously finalize its 

draft sulfur dioxide regulations for the State’s coal plants. 

On June 22, 2010, the U.S. Environmental Protection Agency (EPA) published a new 

primary National Ambient Air Quality Standard (NAAQS) for SO2. This standard—75 ppb as a 

1-hour average—was intended to address adverse health impacts of short-term exposure to SO2.

3

 

 

1

Sierra Club v. McCarthy, Case No. 3:13-cv-3953-SI, Consent Decree (approved Mar. 2, 2015), attached as Exhibit 

1.

2 Wingra Engineering, C.P. Crane Generating Station, Chase, Maryland, Brandon Shores & H.A. Wagner 

Generation Stations, Fort Smallwood Complex, Maryland, Evaluation of Compliance with the 1-hour NAAQS for 

SO2, at 3 Tbl. 1 (May 4, 2015), attached as Exhibit 2.

3 Exposure to sulfur dioxide (SO2) even in very short time periods—as short as five minutes—has been shown to 

cause significant adverse human health effects. Sulfur dioxide causes decrements in lung function, aggravation of 

asthma, and respiratory morbidity. See EPA, Integrated Science Assessment for Sulfur Oxides – Health Criteria, 

EPA/600/R-08/047F, ch. 5 tbls. 5-1, 5-2 (2008); Primary National Ambient Air Quality Standard for Sulfur Dioxide 

Final Rule, 75 Fed. Reg. 35,520, 35,525 (June 22, 2010) (hereinafter ―SO2 Final Rule‖); see also EPA, Our 

Nation‘s Air: Status and Trends Through 2008 at 4 (2010) (noting that the health effects of sulfur dioxide exposure 

include aggravation of asthma and chest tightness) (hereinafter ―Out Nation‘s Air‖), available at 

http://www.epa.gov/airtrends/2010/report/fullreport.pdf. Short-term SO2 exposure is especially risky for children, 
Mr. George (Tad) Aburn

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June 18, 2015

Consistent with the guidance provided in the preamble to EPA’s final rule, which encouraged 

states to take “early action to address potential violations of the NAAQS before they occur” in 

order to avoid the need for nonattainment designations,4,5in October 2013, the Department 

commenced a stakeholder process to address SO2 emissions from Maryland’s coal plants. 

Addressing emissions from these facilities is particularly critical because Maryland’s seven coal 

plants account for over 43% of all SO2 emissions in the State and comprise nearly all of 

Maryland’s largest individual SO2 sources.6

In January 2014, as part of the ongoing stakeholder process, MDE released a draft 

regulation for SO2 emissions from the State’s coal-fired power plants. The regulation established 

1-hour SO2 emission limits in lb/hr for each coal unit in the State that air dispersion modeling 

demonstrated was necessary to insure the facilities’ emissions do not cause or contribute to 

violations of the 2010 1-hour SO2 NAAQS. Since that date, however, MDE has taken no action 

to further develop or finalize this regulation. 

On March 2, 2015, the U.S. District Court for the Northern District of California 

approved a consent decree7requiring the EPA, no later than September 2016, to finalize 

designations for undesignated areas containing stationary sources that emitted more than 2,600 

tons of SO2 and had an annual average emission rate of 0.45 lb SO2/MMBtu or higher in 2012. 

Based on data from EPA’s Air Markets Database, the two coal units at the H.A. Wagner coal 

plant in Maryland emitted 7,430.0 tons of SO2 in 2012 with an average emission rate of 1.176 lb 

SO2/MMBtu.8 Consequently, EPA must finalize its designation for the area containing the 

Wagner plant no later than September 2016. Consistent with this designation deadline, the 

Department is required to submit its designation recommendations to EPA no later than 

September 2015. 

In order to avoid a nonattainment designation for the area surrounding the Wagner plant, 

which also contains the Brandon Shores and Crane plants, the Sierra Club urges the Department 

to submit to EPA as part of its package a final rule establishing modeling-informed SO2 limits for 

 

the elderly, and asthmatics. See EPA, Sulfur Dioxide – Health, available at 

http://www.epa.gov/air/sulfurdioxide/health.html. And EPA has determined that SO2 exposure can aggravate 

existing heart disease, leading to increased hospitalizations and premature deaths. Id.

4

SO2 Final Rule at 35,576/2.

5 As the Sierra Club has previously identified in correspondence to the Governor and the Department, Maryland has 

an independent legal obligation to include enforceable emission limits in its Infrastructure State Implementation 

Plan for the 2010 1-hour SO2 NAAQS pursuant to Section 110(a)(2)(A) of the Clean Air Act, 42 U.S.C. 

§ 7410(a)(2)(A). See, e.g., Ltr. from Joshua Berman, Associate Attorney, Sierra Club, Diana Dascalu-Joffe, Senior 

General Counsel, Chesapeake Climate Action Network, and Tim Whitehouse, Director, Chesapeake Chapter of the 

Physicians for Social Responsibility to Governor Martin O’Malley (Aug. 14, 2013). 

6 According to EPA’s most current National Emission Inventory, in 2011, the seven coal plants emitted 31,088 tons 

of SO2 out of a statewide total from all sources of 71,945 tons. See 

http://www.epa.gov/ttnchie1/net/2011inventory.html and linked fusion table for SO2 emissions. 

7

Sierra Club v. McCarthy, Case No. 3:13-cv-3953-SI, Consent Decree (approved Mar. 2, 2015). 

8 Total SO2 (tons) from Wagner coal units in 2012 = Unit 2 SO2 (tons) + Unit 3 SO2 (tons) = 2,512.8 + 4,960.2 tons 

= 7,473.0 tons SO2. Average SO2 (lb/MMBtu) from Wagner coal units in 2012 = Total SO2 (tons) * 2000 (lb/ton) / 

Total Heat Input (MMBtu) = [(2,512.8 + 4,960.2) tons * 2,000 lb/ton] / [(4,438,743 + 8,271,872) MMBtu] = 1.176 

lb/MMBtu. 
Mr. George (Tad) Aburn

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June 18, 2015

these three plants that are sufficiently stringent and with an appropriately limited averaging time 

to ensure that the NAAQS will be attained and maintained in the area around these plants. 

Previously, in November 2011, the Sierra Club provided the Department with the results of SO2

air dispersion modeling conducted by Gray Sky Solutions using meteorological data from 2006 

to 2010. This modeling was based on steady state emissions at maximum actual and permitted 

allowable emission rates for the facilities and identified significant exceedances of the 2010 1-

hour SO2 NAAQS in the vicinity of the Crane and Wagner plants. In May 2015, the Sierra Club 

retained Wingra Engineering to update the modeling for these facilities by incorporating the 

most current (2012-2014) meteorological data using the newest versions of AERMOD, 

AERMET and AERSURFACE, and including the impacts of Brandon Shores. The updated 

modeling also includes time series modeling of the Baltimore area coal plants individually and 

collectively. 

The updated modeling demonstrates both that the emissions from the Ft. Smallwood 

(Wagner and Brandon Shores) units individually and the Baltimore units (Wagner, Brandon 

Shores and Crane) collectively cause exceedances of the SO2 NAAQS based on actual historical 

emissions and actual historical meteorological data from 2012 – 2014. Moreover, the modeling 

continues to demonstrate that the current permit limits are grossly insufficient, both in emission 

rate and averaging time, to prevent violations of the 1-hour SO2 NAAQS. Instead, the collective 

emission from the Ft. Smallwood complex must be no higher than 3,737 lb/hr as an hourly rate, 

and emissions from the three plants collectively must be no higher than 5,466 lb/hr as an hourly

rate to ensure attainment and maintenance of the NAAQS.9 These results are strongly consistent 

with the modeling results from MDE’s 2013 modeling and with the emission limits in the 

January 2014 draft regulation. 

Given the impending September 2015 deadline for the Department to submit its 

designation recommendations to EPA for the Baltimore area, the Sierra Club urges MDE to 

move forward expeditiously with finalization of its January 2014 SO2 regulation to establish 

enforceable, modeling-informed 1-hour SO2 emission limits for the Baltimore area coal plants in 

order to ensure that their emissions do not cause or contribute to violations of the NAAQS. By 

submitting this regulation to EPA as part of Maryland’s designation recommendation, Maryland 

can avoid the nonattainment designation, which would otherwise be required for the area around 

these plants. 

Thank you for your consideration and please do not hesitate to contact me with any 

questions regarding the updated modeling. 

Respectfully submitted,

Joshua Berman

Staff Attorney

 

9 May 4, 2015 modeling report at 4, Tbl. 3. 
Mr. George (Tad) Aburn

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June 18, 2015

Sierra Club Environmental Law Program

50 F St. NW, 8th Floor

Washington, DC 20001

Tel: (202) 650-6062

Email: Josh.Berman@sierraclub.org

Cc: Randy Mosier

Michael Woodman
EXHIBIT 1
[PROPOSED] CONSENT DECREE 

CASE NO.: 3:13-cv-3953-SI 

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SAM HIRSCH 

Acting Assistant Attorney General 

Environment and Natural Resources Division 

MARTHA C. MANN 

U.S. Department of Justice 

Environmental Defense Section 

P.O. Box 7611 

Washington, D.C. 20044 

Tel: (202) 514-2664 

Fax: (202) 514-8865 

Email: martha.mann@usdoj.gov 

Attorneys for Defendant Gina McCarthy, 

Administrator, United States 

Environmental Protection Agency 

[Additional counsel listed on signature page] 

IN THE UNITED STATES DISTRICT COURT 

FOR THE NORTHERN DISTRICT OF CALIFORNIA 

SAN FRANCISCO DIVISION 

SIERRA CLUB and NATURAL 

RESOURCES DEFENSE COUNCIL, 

 Plaintiffs, 

 

 v. 

GINA MCCARTHY, in her official 

capacity as Administrator of the United 

States Environmental Protection Agency, 

 Defendant. 

Case No.: 3:13-cv-3953-SI 

[PROPOSED] CONSENT DECREE 

 

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[PROPOSED] CONSENT DECREE 

CASE NO.: 3:13-cv-3953-SI 

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WHEREAS, on August 26, 2013, Plaintiffs Sierra Club and Natural Resources Defense 

Council (“Plaintiffs”) filed the complaint (“Complaint”) in the above-captioned matter against 

Defendant Regina McCarthy in her official capacity as Administrator of the United States 

Environmental Protection Agency (“EPA”) alleging that EPA has failed to undertake a certain 

nondiscretionary duty under the Clean Air Act (“CAA”), 42 U.S.C. §§ 7401-7671q, and that 

such alleged failure is actionable under section 304(a)(2) of the CAA, 42 U.S.C. § 7604(a)(2); 

WHEREAS, within one year after promulgation of a revised national ambient air 

quality standard (“NAAQS”), section 107(d)(1)(A) of the CAA directs states to submit lists of 

initial designations of all areas, or portions thereof, as attainment, nonattainment, or 

unclassifiable for the revised NAAQS, 42 U.S.C. § 7407(d)(1)(A); 

WHEREAS, EPA is required to promulgate designations for all areas of the country 

(including tribal areas and certain U.S. territories) within two years of promulgation of the 

revised NAAQS, or within three years if EPA has insufficient information to promulgate the 

designations within two years, pursuant to section 107(d)(1)(B) of the CAA, 42 U.S.C. 

§ 7407(d)(1)(B); 

WHEREAS, EPA is required to publish a notice in the Federal Register promulgating 

designations, pursuant to section 107(d)(2)(A) of the CAA, 42 U.S.C. § 7407(d)(2)(A); 

WHEREAS, EPA revised the primary NAAQS for sulfur dioxide (“SO2”) on June 2, 

2010, see 75 Fed. Reg. 35,520 (June 22, 2010); 

WHEREAS, states were directed to submit their area designations for the 2010 revised 

primary SO2 NAAQS by June 2, 2011, see 75 Fed. Reg. at 35,385/col. 2; 

WHEREAS, on August 3, 2012, EPA invoked the additional year to issue designations, 

see 77 Fed. Reg. 46,295 (Aug. 3, 2012); 

WHEREAS, on August 5, 2013, EPA published designations under the 2010 revised 

primary SO2 NAAQS for twenty-nine areas in sixteen states, thus removing such areas from 

the potential scope of the above-captioned matter, see 78 Fed. Reg. 47,191 (Aug. 5, 2013); 

WHEREAS, the Complaint alleges that EPA has a nondiscretionary duty to promulgate 

and publish the remaining area designations for the 2010 revised primary SO2 NAAQS within 

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[PROPOSED] CONSENT DECREE 

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the time lines set forth in section 107(d)(1)(B) of the CAA, 42 U.S.C. § 7407(d)(1)(B), 

(d)(2)(A); 

WHEREAS, on October 29, 2013, Plaintiffs filed a Motion for Summary Judgment on 

the issue of liability in the above-captioned matter, reserving for future briefing the issue of 

remedy; 

WHEREAS, on November 12, 2013, EPA filed its response to Plaintiffs’ Motion for 

Summary Judgment and did not dispute the claim of liability; 

WHEREAS, on December 6, 2013, the Court granted Plaintiffs’ Motion for Summary 

Judgment, and directed the parties to meet and confer on the remedy; 

WHEREAS, the Plaintiffs and EPA have agreed to a settlement of this action; 

WHEREAS, the Plaintiffs and EPA, by entering into this Consent Decree, do not waive 

or limit any claim or defense, on any grounds, related to any EPA final action; 

WHEREAS, the Plaintiffs and EPA consider this Consent Decree to be an adequate and 

equitable resolution of all the claims in this matter; 

WHEREAS, it is in the interest of the public, the Plaintiffs and EPA, and judicial 

economy to resolve this matter without unnecessary protracted litigation; 

WHEREAS, the Administrator has proposed and anticipates promulgating a 

rulemaking that would direct states to conduct additional information collection and analyses 

regarding certain stationary sources of SO2, for purposes of informing future area designations 

under the 2010 revised primary SO2 NAAQS, see 79 Fed. Reg. 27,449 (May 13, 2014); 

WHEREAS, the Plaintiffs and EPA agree that this Court has jurisdiction over this 

matter pursuant to the citizen suit provision of section 304(a)(2) of the CAA, 42 U.S.C. 

§ 7604(a)(2); 

WHEREAS, the Court, by entering this Consent Decree, finds that the Consent Decree 

is fair, reasonable, in the public interest, and consistent with the CAA; 

NOW THEREFORE, before the taking of testimony, without trial or determination of 

any additional issue of fact or law that the Court has not already addressed in this matter, and 

upon consent of the Plaintiffs and EPA, it is hereby ordered, adjudged and decreed, that: 

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1. EPA shall sign for publication in the Federal Register no later than sixteen (16) 

months from the date of this Court’s entry of this Order a notice of EPA’s promulgation of 

designations for the 2010 revised primary SO2 NAAQS pursuant to section 107(d) of the CAA, 

and within ten (10) business days following such signature deliver the notice to the Office of 

the Federal Register for review and prompt publication, for remaining undesignated areas 

which: 

(a) based on air quality monitoring in the three (3) full calendar years preceding 

such deadline have monitored violations of the 2010 revised primary SO2

NAAQS; or 

(b) contain any stationary source that has not been “announced for retirement” 

pursuant to subparagraph (c) by the date of this Consent Decree, and that, 

according to the data in EPA’s Air Markets Database, either (1) emitted more 

than 16,000 tons of SO2 in 2012, or (2) emitted more than 2,600 tons of SO2 and 

had an annual average emission rate of 0.45 lbs SO2/Mmbtu or higher in 2012; 

where 

(c) “announced for retirement” means any stationary source in the United States 

with a coal-fired unit that as of January 1, 2010, had a capacity of over five (5) 

megawatts (MW) and that has announced that it will cease burning coal at that 

unit through a company public announcement, public utilities commission 

filing, consent decree, public legal settlement, final state or federal permit filing, 

or other similar means of communication. 

2. EPA shall sign for publication in the Federal Register no later than December 

31, 2017, a notice of EPA’s promulgation of designations for the 2010 revised primary SO2

NAAQS pursuant to section 107(d) of the CAA, and within ten (10) business days following 

such signature deliver the notice to the Office of the Federal Register for review and prompt 

publication, for remaining undesignated areas in which, by January 1, 2017, states have not 

installed and begun operating a new SO2 monitoring network meeting EPA specifications 

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[PROPOSED] CONSENT DECREE 

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referenced in EPA’s anticipated rulemaking directing states to collect and analyze additional 

information regarding SO2 emissions concentrations. 

3. EPA shall sign for publication in the Federal Register no later than December 

31, 2020, a notice of EPA’s promulgation of designations for the 2010 revised primary SO2

NAAQS pursuant to section 107(d) of the CAA, and within ten (10) business days following 

such signature deliver the notice to the Office of the Federal Register for review and 

publication, for all remaining undesignated areas. 

4. After EPA’s obligations under Paragraphs 1 through 3 have been completed, 

and after the notices required by Paragraphs 1 through 3 have been published in the Federal 

Register, EPA may move to terminate the Consent Decree. The Plaintiffs shall have fourteen 

(14) days in which to respond to such motion. 

5. Following delivery of the notices of promulgation of designations described in 

Paragraphs 1 through 3 to the Office of the Federal Register, EPA shall not take any action 

(other than is necessary to correct any typographical errors or other errors in form) to delay or 

otherwise interfere with publication of such notices in the Federal Register. EPA shall make 

available to the Plaintiffs copies of the notices within five (5) business days following 

signature by the Administrator. 

6. The Plaintiffs and EPA may extend the deadlines established in Paragraphs 1 

through 3 for a period of sixty (60) days or less by written stipulation executed by counsel for 

the Plaintiffs and EPA and filed with the Court. In addition, the deadlines established in 

Paragraphs 1 through 3 may be extended by the Court upon motion by any party to this 

Consent Decree for good cause shown, after consideration of any response by the non-moving 

party to this Consent Decree. Any party to this Consent Decree seeking to extend deadlines by 

motion and without stipulation must provide written notice to all other parties to this Consent 

Decree of the deadlines the party is seeking to extend at least ten (10) business days prior to 

filing with the Court such motion. No motion to extend a deadline shall be considered properly 

filed unless notice pursuant to this Paragraph is provided, or the moving party demonstrates 

why it could not have provided the advance written notice. 

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7. Nothing in this Consent Decree shall be construed to limit or modify the 

discretion accorded EPA by the CAA and by general principles of administrative law, 

including the discretion to alter, amend or revise any response and/or final action contemplated 

by this Consent Decree. EPA’s obligations to take the actions set forth in Paragraphs 1 through 

3 by the dates specified do not constitute limitations or modifications of EPA’s discretion 

within the meaning of this paragraph. 

8. Nothing in this Consent Decree shall be construed to confer upon the District 

Court jurisdiction to review any final decision made by EPA pursuant to this Consent Decree. 

Nothing in this Consent Decree shall be construed to confer upon the District Court jurisdiction 

to review any issues that are within the exclusive jurisdiction of the United States Court of 

Appeals pursuant to section 307(b)(1) of the CAA, 42 U.S.C. § 7607(b)(1). Nothing in the 

terms of this Consent Decree shall be construed to waive any remedies or defenses the parties 

may have under CAA section 307(b)(1), 42 U.S.C. § 7607(b)(1). 

9. This Court shall retain jurisdiction to enforce the terms of this Consent Decree 

and to consider any requests for costs of litigation, including attorneys’ fees. 

10. In the event of a dispute between the parties to this Consent Decree 

concerning the interpretation or implementation of any aspect of this Consent Decree, the 

disputing party shall provide the other party with a written notice outlining the nature of the 

dispute and requesting informal negotiations. If the parties cannot reach an agreed-upon 

resolution within ten (10) business days after receipt of notice, any party may move the Court 

to resolve the dispute. 

11. No motion or other proceeding seeking to enforce this Consent Decree shall 

be considered properly filed, unless the Plaintiffs have followed the procedure set forth in 

Paragraph 10. 

12. The United States, on behalf of EPA, agrees that the Plaintiffs are entitled to 

recover their costs of litigation (including reasonable attorneys’ fees) (“litigation costs”) 

incurred in this matter pursuant to 42 U.S.C. § 7604(d). The deadline for filing a motion for 

litigation costs is hereby extended until 120 days after entry of this Consent Decree by the 

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Court. During this time, the Plaintiffs and EPA shall seek to resolve informally any claim for 

litigation costs, and if they cannot reach a resolution, the Plaintiffs may seek such litigation 

costs from the Court. The Court shall retain jurisdiction to resolve any request for litigation 

costs. 

13. The obligations imposed upon EPA by this Consent Decree may only be 

undertaken using appropriated funds. No provisions of this Consent Decree shall be 

interpreted as or constitute a commitment or requirement that EPA obligate or pay funds in 

contravention of the Anti-Deficiency Act, 31 U.S.C. § 1341, or any other applicable federal 

law. 

14. The parties recognize that the possibility exists that a lapse in the 

appropriations that fund EPA could delay compliance with the timetables contained in this 

Consent Decree. Should a delay occur due to a lapse in appropriations, any deadlines 

occurring within ninety (90) days of the termination of the delay shall be extended one day for 

each day of the delay. EPA will provide Plaintiffs with notice as soon as is reasonably possible 

under the circumstances in the event that EPA invokes this Paragraph of the Consent Decree 

and will provide Plaintiffs with an explanation of EPA's basis for invoking this Paragraph. 

Plaintiffs may challenge the invocation of this Paragraph of the Consent Decree under the 

dispute resolution terms of this Consent Decree, and EPA shall bear the burden of justifying its 

invocation of this Paragraph. 

15. The Plaintiffs and EPA shall not challenge the terms of this Consent Decree or 

this Court’s jurisdiction to enter this Consent Decree. 

16. The Plaintiffs and EPA agree and acknowledge that before this Consent 

Decree is entered by the Court, EPA must provide notice of this Consent Decree in the Federal 

Register and provide an opportunity for public comment pursuant to section 113(g) of the 

CAA, 42 U.S.C. § 7413(g). After this Consent Decree has undergone notice and comment, the 

Administrator and/or the Attorney General, as appropriate, shall promptly consider any such 

written comments in determining whether to withdraw or withhold their consent to the Consent 

Decree, in accordance with section 113(g) of the CAA. If the Administrator and/or the 

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[PROPOSED] CONSENT DECREE 

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Attorney General do not elect to withdraw and withhold their consent, EPA shall promptly file 

a motion that requests the Court to enter this Consent Decree. 

17. Any notices required or provided by this Consent Decree shall be made in 

writing, via facsimile, e-mail, or other means, and sent to the following: 

For Plaintiffs: 

 Nicholas Morales 

 David S. Baron 

 Earthjustice 

 1625 Massachusetts Ave., STE 702 

 Washington, DC 20036 

 nmorales@earthjustice.org 

 dbaron@earthjustice.org 

 Fax: 202-667-2356 

 Zachary M. Fabish 

 The Sierra Club 

 50 F Street, NW – 8th Floor 

 Washington, DC 20001 

 zachary.fabish@sierraclub.org 

 Fax: 202-547-6009 

 Emily K. Davis 

 Natural Resources Defense Council 

 1152 15th Street, NW, Suite 300 

 Washington, DC 20005 

 edavis@nrdc.org 

 Fax: 202-289-1060 

For Defendant: 

 

 Martha C. Mann 

 United States Department of Justice 

 Environmental Defense Section 

 P.O. Box 7611 

 Washington, DC 20044 

 martha.mann@usdoj.gov 

 Fax: 202-514-8865 

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COUNSEL FOR DEFENDANT:

Dated: ~) us~- ~ ~'LQ~~

~~~

SO ORDERED on this day of

SAM HIRSCH

Acting Assistant Attorney General

Environment &Natural Resources Division

MARTHA C. MANN

United States Department of Justice

Environment &Natural Resources Division

P.O. Box 7611

Washington, D.C. 20044

Tel: (202) 514-2664

E-mail: martha.mann(a~usdoj~ov_

Counsel for Defendant EPA

2014

SUSAN ILLSTON

United States District Judge

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[PROPOSED] CONSENT DECREE

CASE No.: 3:13-cv-3953-SI

2nd March

Case3:13-cv-03953-SI Document163 Filed03/02/15 Page10 of 10
EXHIBIT 2
C.P. Crane Generating Station 

Chase, Maryland 

Brandon Shores & H.A. Wagner Generating Stations 

Fort Smallwood Complex, Maryland 

Evaluation of Compliance with the 1-hour NAAQS for SO2 

May 4, 2015 

Conducted by: 

Steven Klafka, P.E., BCEE 

Wingra Engineering, S.C. 

Madison, Wisconsin
Evaluation of Compliance with the 1-hour NAAQS for SO2

May 4, 2015 

Page 2

1. Introduction 

Wingra Engineering, S.C. was hired by the Sierra Club to conduct an air modeling impact analysis to 

help USEPA, state and local air agencies identify facilities that are likely causing exceedences of the 

1-hour sulfur dioxide (SO2) national ambient air quality standard (NAAQS). This document

describes the results and procedures for an evaluation conducted for three Maryland generating 

stations located near Baltimore, Maryland. These three stations include C.P. Crane Generating 

Station in Chase, Maryland and Brandon Shores & H.A. Wagner Generating Stations at the Fort 

Smallwood Complex in Maryland. This analysis updates the 2011 report prepared by Gray Sky 

Solutions by incorporating emissions from the most recent three years (2012-2014), incorporating 

the emissions from the Brandon Shores facility, and using the most current version of EPA’s 

AERMOD and related software. 1 

The dispersion modeling analysis predicted ambient air concentrations for comparison with the 1-

hour SO2 NAAQS. The modeling was performed using the most recent version of AERMOD, 

AERMET, and AERMINUTE, with data provided to the Sierra Club by regulatory air agencies and 

through other publicly-available sources as documented below. The analysis was conducted in 

adherence to all available USEPA guidance for evaluating source impacts on attainment of the 1-

hour SO2 NAAQS via aerial dispersion modeling, including the AERMOD Implementation Guide; 

USEPA's Applicability of Appendix W Modeling Guidance for the 1-hour SO2 National Ambient 

Air Quality Standard, August 23, 2010; modeling guidance promulgated by USEPA in Appendix W 

to 40 CFR Part 51; USEPA’s March 2011 Modeling Guidance for SO2 NAAQS Designations; 2 and, 

USEPA’s December 2013 SO2 NAAQS Designations Technical Assistance Document.3 

2. Compliance with the 1-hour SO2 NAAQS 

2.1 1-hour SO2 NAAQS 

The 1-hour SO2 NAAQS takes the form of a three-year average of the 99th-percentile of the annual 

distribution of daily maximum 1-hour concentrations, which cannot exceed 75 ppb.4 Compliance 

with this standard was verified using USEPA’s AERMOD air dispersion model, which produces air 

concentrations in units of μg/m3. The 1-hour SO2 NAAQS of 75 ppb equals 196.2 μg/m3, and this is 

the value used for determining whether modeled impacts exceed the NAAQS.5 The 99th-percentile 

 

1 Gray Sky Solutions, Modeling the Short-term SO2 Impacts Due to Wagner and Crane Power Plant Emissions, 

September 2011. 

2

 http://www.epa.gov/scram001/so2_modeling_guidance.htm 

3

 http://www.epa.gov/oaqps001/sulfurdioxide/pdfs/SO2ModelingTAD.pdf 4 USEPA, Applicability of Appendix W Modeling Guidance for the 1-hour SO2 National Ambient Air Quality Standard, 

August 23, 2010.

5 The ppb to μg/m3

 conversion is found in the source code to AERMOD v. 14134, subroutine Modules. The conversion 

calculation is 75/0.3823 = 196.2 μg/m3

. 
Evaluation of Compliance with the 1-hour NAAQS for SO2

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of the annual distribution of daily maximum 1-hour concentrations corresponds to the fourth-highest 

value at each receptor for a given year. 

2.2 Modeling Results 

Modeling results for the three Maryland generating stations are summarized in Table 1. It was 

determined that based on either current allowable emissions, peak maximum emissions, or measured 

actual emissions, the three Maryland generating stations are estimated to create downwind SO2

concentrations which exceed the 1-hour NAAQS. 

More specifically, the modeling results presented in Table 1, show exceedences of the NAAQS by 

the plant’s allowable, maximum and actual emissions. “Allowable” is the peak emission rate from 

each unit as approved by the current air quality operation permit for the facility. “Maximum” is the 

peak hourly emissions which at each location between January 1, 2012 and December 31, 2014 as 

taken from USEPA Air Markets Program Data.

6

 “Actual” represents the emissions which occurred 

during each hour during the between January 1, 2012 and December 31, 2014 period. 

Air quality impacts in Maryland are based on a background concentration of 26.2 μg/m3. This is the 

2011-13 design value for Prince George's, Maryland - the lowest measured background 

concentration in the state. This is the most recently available design value. See Section 5 for further 

discussion of the background concentrations used for this analysis. 

Table 1 - SO2 Modeling Results for the Three Maryland Generating Stations 

Power 

Plant(s) 

Emission 

Rates 

99th Percentile 1-hour Daily Maximum (μg/m3) NAAQS Meets 

NAAQS? 

Impact Background Total (μg/m3) (μg/m3) 

All Allowable 1,261.2 26.2 1,287.4 196.2 No 

Crane Allowable 826.7 26.2 852.9 196.2 No 

Brandon/Wagner Allowable 1,250.9 26.2 1,277.1 196.2 No 

All Maximum 561.0 26.2 587.2 196.2 No 

Crane Maximum 478.0 26.2 504.2 196.2 No 

Brandon/Wagner Maximum 468.4 26.2 494.6 196.2 No 

All Actual 267.7 26.2 293.9 196.2 No 

Crane Actual 103.9 26.2 130.1 196.2 Yes 

Brandon/Wagner Actual 265.3 26.2 291.5 196.2 No 

 

 

6

 http://ampd.epa.gov/ampd/ 
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The emissions used for the modeling analysis are summarized in Table 2. 

Table 2 - Modeled SO2 Emissions from the Three Maryland Generating Stations 7

Power 

Plant (s) Unit 

Heat 

Input 

(mmbtu/hr) 

Allowable 

Emissions 

(Averaging 

Period) 

Allowable 

Emissions 

(lbs/mmbtu) 

Allowable 

Emissions 

(lbs/hr) 

Maximum 

Emissions 

(lbs/hr) 

Crane 

C01 1,865 24-hours 3.5 6,527.5 2,966.7 

C02 1,865 24-hours 3.5 6,527.5 4,574.1 

All Units 3,730 13,055.0 7,540.8 

Brandon Shores 

& 

Wagner 

B01 7,128 1.0% Coal Sulfur 1.5 10,692.0 2,112.1 

B02 7,128 1.0% Coal Sulfur 1.5 10,692.0 1,511.1 

W02 1,337 1.0% Coal Sulfur 1.5 2,005.5 2,445.4 

W03 2,740 1.0% Coal Sulfur 1.5 4,110.0 3,205.2 

All Units 18,333 27,499.5 9,273.8 

All Power Plants All Units 22,063 40,555 16,815 

Based on the modeling results, Table 3 provides the necessary emission reductions from current 

allowable rates necessary to achieve compliance with the 1-hour NAAQS. 

Table 3 - Required Emission Reductions for Compliance with the 1-hour NAAQS for SO2 

Power 

Plant (s) 

Acceptable 

Impact 

(μg/m3

) 

Required 

Reduction 

(%) 

Required 

Emissions 

(lbs/hr) 

Required 

Emissions 

(lbs/mmbtu) 

All 170.0 86.5% 5,466.4 0.25

Crane 170.0 79.4% 2,684.6 0.72

Brandon / Wagner 170.0 86.4% 3,737.2 0.20

Predicted exceedences of the 1-hour NAAQS for SO2 based on allowable emissions extend 

throughout the region to a maximum distance of the modeling domain of 25 kilometers. 

Figures 1 through 5 show the extent of predicted exceedences of the 1-hour NAAQS for SO2 based 

on the allowable emissions from all three plants, the C.P. Crane Generating Station by itself, and the 

Brandon Shores and H.A. Wagner Generating Stations by themselves. 

 

7

 Allowable emissions for Crane are based on Maryland Department of Natural Resources, Part 70 Operating Permit No. 

24-005-00079, March 1, 2009. Allowable emissions for Brandon Shores and Wagner are based on Maryland Department 

of Natural Resources, Part 70 Operating Permit No. 24-003-00468, May 1, 2011. 
Evaluation of Compliance with the 1-hour NAAQS for SO2

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2.3 Conservative Modeling Assumptions 

A dispersion modeling analysis requires the selection of numerous parameters which affect the 

predicted concentrations. For the enclosed analysis, several parameters were selected which underpredict facility impacts. 

Assumptions used in this modeling analysis which likely under-estimate concentrations include the 

following: 

 Allowable emissions are based on a limitation with an averaging period which is greater than 

the 1-hour average used for the SO2 air quality standard. Emissions and impacts during any 

1-hour period may be higher than assumed for the modeling analysis. 

 No consideration of facility operation at less than 100% load. Stack parameters such as exit 

flow rate and temperature are typically lower at less than full load, reducing pollutant 

dispersion and increasing predicted air quality impacts. 

 No consideration of building or structure downwash. These downwash effects typically 

increase predicted concentrations near the facility. 

 No evaluation has been conducted to determine if the stack height exceeds Good Engineering 

Practice or GEP height. If the stack height exceeds GEP, the predicted concentrations will 

increase. 

 No consideration of off-site sources. These other sources of SO2 will increase the predicted 

impacts.
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Figure 1 - Regional View of Impacts Due to Allowable Emissions from All Three Plants 
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Figure 2 - Regional View of Impacts Due to Allowable Emissions from C.P. Crane 

 
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Figure 3 - Local View of Impacts Due to Allowable Emissions from C.P. Crane
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Figure 4 - Regional View of Impacts Due to Allowable Emissions from Brandon Shores & Wagner 

 
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Figure 5 - Local View of Impacts Due to Allowable Emissions from Brandon Shores & Wagner 

 
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3. Modeling Methodology 

3.1 Air Dispersion Model 

The modeling analysis used USEPA’s AERMOD program, v. 14134. AERMOD, as available from 

the Support Center for Regulatory Atmospheric Modeling (SCRAM) website, was used in 

conjunction with a third-party modeling software program, AERMOD View, sold by Lakes 

Environmental Software. 

3.2 Control Options 

 

The AERMOD model was run with the following control options: 

 1-hour average air concentrations 

 Regulatory defaults 

 Flagpole receptors 

To reflect a representative inhalation level, a flagpole height of 1.5 meters was used for all modeled 

receptors. This parameter was added to the receptor file when running AERMAP, as described in 

Section 4.4. 

An evaluation was conducted to determine if the modeled facilities are located in a rural or urban 

setting using USEPA’s methodology outlined in Section 7.2.3 of the Guideline on Air Quality 

Models.8

 For urban sources, the URBANOPT option is used in conjunction with the urban 

population from an appropriate nearby city and a default surface roughness of 1.0 meter. Methods 

described in Section 4.1 were used to determine whether rural or urban dispersion coefficients were 

appropriate for the modeling analysis. 

 

3.3 Output Options 

The AERMOD analysis was based on three years of recent meteorological data. The modeling 

analyses used one run with three years of sequential meteorological data from 2012-2014. Consistent 

with USEPA’s Modeling Guidance for SO2 NAAQS Designations, AERMOD provided a table of 

fourth-high 1-hour SO2 impacts concentrations consistent with the form of the 1-hour SO2 NAAQS.9 

Please refer to Table 1 for the modeling results. 

 

8

 USEPA, Revision to the Guideline on Air Quality Models: Adoption of a Preferred General Purpose (Flat and Complex 

Terrain) Dispersion Model and Other Revisions, Appendix W to 40 CFR Part 51, November 9, 2005.

9 USEPA, Area Designations for the 2010 Revised Primary Sulfur Dioxide National Ambient Air Quality Standards, 

Attachment 3, March 24, 2011, pp. 24-26. 
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4. Model Inputs 

4.1 Geographical Inputs 

The “ground floor” of all air dispersion modeling analyses is establishing a coordinate system for 

identifying the geographical location of emission sources and receptors. These geographical 

locations are used to determine local characteristics (such as land use and elevation), and also to 

ascertain source to receptor distances and relationships. 

The Universal Transverse Mercator (UTM) NAD83 coordinate system was used for identifying the 

easting (x) and northing (y) coordinates of the modeled sources and receptors. Stack locations were 

obtained from facility permits and prior modeling files provided by the state regulatory agency. The 

stack locations were then verified using aerial photographs. 

The facility was evaluated to determine if it should be modeled using the rural or urban dispersion 

coefficient option in AERMOD. A GIS was used to determine whether rural or urban dispersion 

coefficients apply to a site. Land use within a three-kilometer radius circle surrounding the facility 

was considered. USEPA guidance states that urban dispersion coefficients are used if more than 50% 

of the area within 3 kilometers has urban land uses. Otherwise, rural dispersion coefficients are 

appropriate.10 

USEPA’s AERSURFACE v. 13016 was used to develop the meteorological data for the modeling 

analysis. This model was also used to evaluate surrounding land use within 3 kilometers. Based on 

the output from the AERSURFACE, approximately 2.6% of the land surrounding the C.P. Crane 

Generating Station and 13.4% of the land surrounding the Brandon Shores and H.A. Wagner 

Generating Stations were of urban land use types including Type 21 – Low Intensity Residential, 

Type 22 – High Intensity Residential and Type 23 – Commercial / Industrial / Transportation. 

This is less than the 50% value considered appropriate for the use of urban dispersion coefficients. 

Based on the AERSURFACE analysis, it was concluded that the rural option would be used for the 

modeling summarized in this report. Please refer to Section 4.5.3 for a discussion of the 

AERSURFACE analysis.

 

 

10 USEPA, Revision to the Guideline on Air Quality Models: Adoption of a Preferred General Purpose (Flat and 

Complex Terrain) Dispersion Model and Other Revisions, Appendix W to 40 CFR Part 51, November 9, 2005, Section 

7.2.3. 
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4.2 Emission Rates and Source Parameters 

The modeling analyses only considered SO2 emissions from the facility. Off-site sources were not 

considered. Concentrations were predicted for the following scenarios: 

1) allowable emissions based on the current permit issued by the regulatory agency, 

2) maximum emissions occurring during any hour between January 1, 2012 and December 

31, 2014 as taken from USEPA Air Markets Program Data.

11 For the Brandon Shores and 

Wagner plants, this hour was based on the total emissions for each hour from all units at their 

location, and, 

2) actual hourly emissions measured during each hour of the January 1, 2012 and December 

31, 2014 period. 

Stack parameters and emissions used for the modeling analysis are summarized in Table 4. 

Table 4 – Facility Stack Parameters and Emissions 12

Stack B01 B02 C01 C02 W02 W03 

Generating Station Brandon Brandon Crane Crane Wagner Wagner 

Boiler/Unit Unit 1 Unit 2 Unit 1 Unit 2 Unit 2 Unit 3 

X Coord. [m] 366970.5 366980.5 382293.8 382335.7 368092 368050 

Y Coord. [m] 4338117.53 4338120.09 4353574.5 4353566.3 4337574 4337602 

Base Elevation [m] 10 9.92 1.27 1.27 3.85 4.1 

Release Height [m] 121.92 121.92 107.59 107.59 87.48 105.46 

Gas Exit Temperature [°K] 326.483 326.483 427.594 427.594 409.817 418.706 

Gas Exit Velocity [m/s] 13.023 11.96 29.942 29.071 22.692 28.733 

Inside Diameter [m] 9.51 9.51 3.322 3.322 3.109 4.206 

Allowable Emission Rate [g/s] 1347 1347 822.5 822.5 252.7 517.9

Maximum Emission Rate [g/s] 266.1 190.4 373.8 576.3 308.1 403.8

Actual Emission Rate [g/s] - - - - - - 

The above stack parameters and emissions were obtained from regulatory agency documents and 

databases identified in Section 2.2. The analysis was conducted based on 100% operating load using 

maximum exhaust flow rates and temperatures. Operation at less than full capacity loads was not 

considered. This assumption tends to under-predict impacts since stack parameters such as exit flow 

rate and temperature are typically lower at less than full load, reducing pollutant dispersion and 

 

11 http://ampd.epa.gov/ampd/ 

12 U.S. Energy Information Agency, Form EIA-860 detailed data, 2013, http://www.eia.gov/electricity/data/eia860/xls/eia8602013.zip
Evaluation of Compliance with the 1-hour NAAQS for SO2

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increasing predicted air quality impacts. Stack location, height and diameter were verified using 

aerial photographs, and flue gas flow rate and temperature were verified using combustion 

calculations. 

4.3 Building Dimensions and GEP 

No building dimensions or prior downwash evaluations were available. Therefore this modeling 

analysis did not address the effects of downwash and this may under-predict impacts. 

4.4 Receptors 

For the three Maryland generating stations, two receptor grids were employed: 

1. A 100-meter Cartesian receptor grid centered on the three Maryland generating stations and 

extending out 15 kilometers. 

2. A 500-meter Cartesian receptor grid centered on the three Maryland generating stations and 

extending out 25 kilometers. 

A flagpole height of 1.5 meters was used for all these receptors. 

Elevations from stacks and receptors were obtained from National Elevation Dataset (NED) GeoTiff 

data. GeoTiff is a binary file that includes data descriptors and geo-referencing information 

necessary for extracting terrain elevations. These elevations were extracted from 1 arc-second (30 

meter) resolution NED files. The USEPA software program AERMAP v. 11103 is used for these 

tasks. 

4.5 Meteorological Data 

To improve the accuracy of the modeling analysis, recent meteorological data for the 2012-2014 

period were prepared using the USEPA’s program AERMET which creates the model-ready surface 

and profile data files required by AERMOD. Required data inputs to AERMET included surface 

meteorological measurements, twice-daily soundings of upper air measurements, and the 

micrometeorological parameters surface roughness, albedo, and Bowen ratio. One-minute ASOS 

data were available so USEPA methods were used to reduce calm and missing hours.13 The USEPA 

software program AERMINUTE v. 14237 is used for these tasks. 

This section discusses how the meteorological data was prepared for use in the 1-hour SO2 NAAQS 

modeling analyses. The USEPA software program AERMET v. 14134 is used for these tasks. 

 

13 USEPA, Area Designations for the 2010 Revised Primary Sulfur Dioxide National Ambient Air Quality Standards, 

Attachment 3, March 24, 2011, p. 19. 
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4.5.1 Surface Meteorology 

Surface meteorology was obtained for Baltimore Washington International Airport located near the 

the three Maryland generating stations. Integrated Surface Hourly (ISH) data for the 2012-2014 

period were obtained from the National Climatic Data Center (NCDC). The ISH surface data was 

processed through AERMET Stage 1, which performs data extraction and quality control checks. 

4.5.2 Upper Air Data 

Upper-air data are collected by a “weather balloon” that is released twice per day at selected 

locations. As the balloon is released, it rises through the atmosphere, and radios the data back to the 

surface. The measuring and transmitting device is known as either a radiosonde, or rawindsonde. 

Data collected and radioed back include: air pressure, height, temperature, dew point, wind speed, 

and wind direction. The upper air data were processed through AERMET Stage 1, which performs 

data extraction and quality control checks. 

For the three Maryland generating stations, the concurrent 2012-2014 upper air data from twicedaily radiosonde measurements obtained at the most representative location were used. This 

location was the Sterling, Virgina measurement station. These data are in Forecast Systems 

Laboratory (FSL) format and were downloaded in ASCII text format from NOAA’s FSL website.14 

All reporting levels were downloaded and processed with AERMET.

4.5.3 AERSURFACE 

AERSURFACE is a program that extracts surface roughness, albedo, and daytime Bowen ratio for 

an area surrounding a given location. AERSURFACE uses land use and land cover (LULC) data in 

the U.S. Geological Survey’s 1992 National Land Cover Dataset to extract the necessary 

micrometeorological data. LULC data was used for processing meteorological data sets used as 

input to AERMOD. 

AERSURFACE v. 13016 was used to develop surface roughness, albedo, and daytime Bowen ratio 

values in a region surrounding the meteorological data collection site. AERSURFACE was used to 

develop surface roughness in a one kilometer radius surrounding the data collection site. Bowen 

ratio and albedo was developed for a 10 kilometer by 10 kilometer area centered on the 

meteorological data collection site. These micrometeorological data were processed for seasonal 

periods using 30-degree sectors. Seasonal moisture conditions were considered average with winter 

months having continuous snow cover. 

 

14 Available at: http://esrl.noaa.gov/raobs/ 
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4.5.4 Data Review 

Missing meteorological data were not filled as the data file met USEPA’s 90% data completeness 

requirement.15 The AERMOD output file shows there were 0.2% missing data. 

To confirm the representativeness of the airport meteorological data, the surface characteristics of 

the airport data collection site and the modeled source location were compared. Since the Baltimore 

Washington International Airport is located close to the three Maryland generating stations, this 

meteorological data set was considered appropriate for this modeling analysis. 16 Additionally, this 

weather station provided high quality surface measurements for the most recent 3-year time, and had 

similar land use, surface characteristics, terrain features and climate. 

5. Background SO2 Concentrations 

Background concentrations were determined consistent with USEPA’s Modeling Guidance for SO2

NAAQS Designations.17 To preserve the form of the 1-hour SO2 standard, based on the 99th

percentile of the annual distribution of daily maximum 1-hour concentrations averaged across the 

number of years modeled, the background fourth-highest daily maximum 1-hour SO2 concentration 

was added to the modeled fourth-highest daily maximum 1-hour SO2 concentration.18 Background 

concentrations were based on the 2011-13 design value measured by the ambient monitors located in 

Maryland.19 

6. Reporting 

All files from the programs used for this modeling analysis are available to regulatory agencies. 

These include analyses prepared with AERSURFACE, AERMET, AERMAP, and AERMOD. 

 

15 USEPA, Meteorological Monitoring Guidance for Regulatory Modeling Applications, EPA-454/R-99-05, February 

2000, Section 5.3.2, pp. 5-4 to 5-5. 

16 USEPA, AERMOD Implementation Guide, March 19, 2009, pp. 3-4. 

17 USEPA, Area Designations for the 2010 Revised Primary Sulfur Dioxide National Ambient Air Quality Standards, 

Attachment 3, March 24, 2011, pp. 20-23. 

18 USEPA, Applicability of Appendix W Modeling Guidance for the 1-hour SO2 National Ambient Air Quality Standard, 

August 23, 2010, p. 3. 

19 http://www.epa.gov/airtrends/values.html