Carroll "Mack" W. McGuffey III


Business Phone: 404.885.3698
Business Fax: 404.962.6808


Mack McGuffey practices environmental law as a partner in Troutman Sanders' Atlanta office and specializes in regulatory compliance and enforcement defense under the Clean Air Act. He represents utility, landfill, and industrial clients on a number of important air quality issues, including federal and state permitting requirements for the construction and operation of industrial sources, as well as applicability of and compliance with industry-specific emission standards. Mack also helps his clients participate in relevant EPA rulemaking actions and challenge those rulemakings when necessary.

Representative Matters

New Source Review and Title V Permitting & Compliance:

  • Advising numerous large electric utility companies across the country on potential New Source Review implications of all capital and significant maintenance projects. 
  • Assisting a glass manufacturer in obtaining a PSD permit for a new facility. 
  • Representing a biomass power facility in response to an objection to its Title V permit granted by EPA and coordination with state permitting authority to address that objection.
  • Advising large landfill company regarding potential permitting implications of purchasing, installing, modifying, or reconstructing landfill gas flares and landfill gas-to-energy projects. 

Environmental Enforcement Defense:

  • Representing two large ethanol production facilities in responding to Clean Air Act Section 114 information requests and Notices and Findings of Violation related to Title V Operating Permit and NESHAP compliance.
  • Defending numerous landfills against multiple findings of violation issued by both state and federal enforcement authorities and assist in permitting needed to resolve those actions.

Environmental Litigation: 

  • Representing coal and utility interests in successful challenge to EPA’s mercury and climate change regulations for the electric utility sector.
  • Assist in representing coal and utility interests in challenges to EPA’s Clean Power Plan.
  • Representing a large landfill company in developing a coalition of waste industry organizations to challenge EPA’s revisions to new source performance standards and emission guidelines for MSW landfills via petitions for judicial review and administrative action. 
  • Represent Georgia industry coalition in challenging EPA’s SSM SIP Call and in assisting state planning authorities with development of a response to the SIP Call.  

Participation in EPA Rulemaking Process:

  • Preparing comments on EPA’s Affordable Clean Energy Rule on behalf of National Mining Association
  • Preparing comments on EPA’s proposed revisions to regional haze rule revisions on behalf of various utility companies.
  • Preparing comments on proposed EPA hazardous air pollutant rule on behalf of a chemical manufacturing client that were quoted and directly incorporated into the final rule. 
  • Preparing comments for Georgia industry coalition to present industry perspective on the practical effect of EPA’s 2002 New Source Review Reform rules and, in 2011, assisting in the development of state-specific guidance for implementing those rules.


  • Assisting several large utility clients with environmental provisions in purchase and sale agreements for power plants located in the southeast and the midwest. 
  • Environmental due diligence counsel for several clients seeking to purchase or sell either new biomass electric generating units or coal-fired units that can be converted to biomass.  


  • Author, "How The Affordable Clean Energy Rule Impacts Oil And Gas," Law360, October 17, 2018.
  • Author, “Look Out—EPA Is Repowering Its Hazy Visibility Program,” Natural Gas & Electricity, September 2016.
  • Author, "2016 to Be Litigation-Heavy, as Obama EPA Wraps Up Its Air Agenda," Natural Gas & Electricity, February 2016.
  • Co-author, “Regulating Greenhouse Gases Under the Clean Air Act: Is the Bubble About to Burst?” George Washington University Law School Journal of Energy and Environmental Law, Winter 2016.
  • Author, “Supreme Court Rules EPA Must Consider Cost,” Terralex Connections, September 2015.
  • Author, "2015 to Be the Year of Final Air-Quality Regulations," Natural Gas & Electricity 31/7, ©2015 Wiley Periodicals, Inc., a Wiley company, February 2015.
  • Author, "NSR Compliance - Are You Ready?" Natural Gas & Electricity, August 2013.
  • Author, “Regulating Carbon,” Turbomachinery International, May/June 2009.
  • Co-author, “Regulating GHGs Under The Clean Air Act,” Law360, Portfolio Media, Inc. (, March 2009.
  • Author, "U.S. high court deals with emissions," Turbomachinery, May/June 2007.
  • Co-author, "Global Warming Solutions: Regulatory Challenges and Common Law Liabilities Associated With The Geologic Sequestration of Carbon Dioxide," Georgetown Law Review, 6 Geo. J.L. & Pub. Pol'y 429; 2008.

Presentations and Speaking Engagements

  • ”Regional Haze: Round 2 Is Just Around the Corner,” Electric Utility & Environment Conference, February 2017.
  • “Air Regulations for Asphalt Companies,” Virginia Asphalt Association, January 2017. 
  • “Compliance with the Clean Power Plan,” Electric Utility & Environment Conference, February 2016
  • "EPA's Clean Power Plan: A Climate Game Changer," Bloomberg BNA Webinar, September 3, 2015.
  • "EPA Issues “SIP Call” Requiring New Rules for Startup, Shutdown, and Malfunction Emissions," Bloomberg BNA Webinar, July 23, 2015. 
  • "Regulatory Update: The Clean Air Act," Southern States Energy Board 2015 Briefing to Southern Legislators, July 18, 2015.
  • Update on Environmental Litigation and Regulatory Issues for Coal-Fired Generation in the US Energy Market,” Law Seminars International 10th Annual Conference on Energy in the Southwest, July 15, 2013.
  • “Practical NSR Compliance,” Energy, Utility, and Environment Conference (EUEC), January 29, 2013.
  • “EPA’s Final Final Industrial Boiler MACT,” Regulation Week Audio Conferences, January 8, 2013.
  • "Managing Environmental Compliance", Georgia Institute of Technology, Semi-annually March 2007 through October 2012.
  • “EPA’s “Non-Hazardous Secondary Materials” (NHSM) Rule,” Energy, Utility, and Environment Conference (EUEC), February 1, 2012.
  • "EPA's MATS Rule: MACT for Utilities," Regulation Week Audio Conferences, December 28, 2011.
  • "FINAL Industrial Boiler and Process Heater MACT,” McIlvaine Hot Topic Hour, March 10, 2011.
  • "New 2011 EPA GHG Emission Regulations," Biowood Energy Audio Conferences, December 17, 2010.
  • "The 'Sum of the Differences:' Applying NSR Math in the Real World," Air & Waste Management, South Atlantic Section 2008 Environmental Management Conference, November 20, 2008.

Professional and Community Involvement

  • State Bar of Georgia (Chairman, Environmental Law Section)

Rankings and Recognition

  • Selected as a Rising Star in Environmental by Georgia Super Lawyers, published by Law & Politics and Atlanta Magazine (2007, 2009, 2011-2016).
  • Recognized in The Best Lawyers in America in Environmental Law (2015-2019).

Professional Experience

  • Partner, Troutman Sanders LLP, 2012-present
  • Associate, Troutman Sanders LLP, 2003-2011



  • University of Georgia, J.D., magna cum laude, 2003
    National Moot Court Team (2001-2003)
    Talmadge Moot Court Competition Winner
    Order of the Coif
  • University of Georgia, B.B.A., 1998

Bar Admissions

  • Georgia

Court Admissions

  • U.S. Supreme Court
  • U.S. Court of Appeals for the District of Columbia
  • Supreme Court of Georgia
  • Georgia Superior Courts
  • Georgia Court of Appeals