Executive Committee



Amy L. EdwardsChair
Amy L. Edwards
Holland & Knight LLP
Washington, DC

Amy Edwards is a Partner at Holland & Knight LLP in Washington, DC, where she co-chairs the firm's national Environment Team. She routinely counsels developers, lenders and corporations about effective strategies for structuring real estate and corporate transactions to minimize environmental and financial risk. She also counsels clients on climate change and sustainability issues, environmental disclosures, and product stewardship issues, and represents companies in enforcement proceedings. She regularly writes and speaks on these topics. Amy has been practicing environmental and energy law for more than thirty-five years.

She chaired the ASTM committee that developed E 2091, Standard Guide for Use of Activity and Use Limitation, Including Institutional and Engineering Controls, and is the author/editor of the ABA book, Implementing Institutional Controls at Brownfields and Other Contaminated Sites (2nd ed., 2012). She was an observer/advisor to the National Conference of Commissioners on Uniform State Laws during its development of the Uniform Environmental Covenants Act (UECA).

Amy has held several leadership positions in the ABA Section of Environment, Energy, and Resources, including as Vice Chair, Education Officer, on its Executive Committee, as Planning Chair for its 21st Fall Conference in Baltimore, MD, as Chair of the Environmental Transactions and Brownfields Committee (ETAB), and as a Vice Chair of the ETAB Committee. Amy also actively served as a member of the Environmental Law Institute's (ELI's) Board of Directors for seven years and serves on the Advisory Board to the Bloomberg BNA Environmental Due Diligence Guide (EDDG). She has been recognized in Chambers USA - America's Leading Business Lawyers guide, Environment Law; in the Best Lawyers in America guide, Environmental Law; in Washington, D.C. Super Lawyers, Environmental Law; and in The International Who's Who of Environment Lawyers.

Amy received her J.D. from The George Washington University Law School, and her A.B. from Smith College. She is a member of the District of Columbia, Maryland, Virginia and American Bar Associations.

Karen MignoneChair-Elect
Karen A. Mignone
Xeros Technology Group
Manchester, CT

Karen serves as Global Director of Sustainability and Environmental Affairs at Xeros Technology Group plc, a polymer technology company based in Sheffield England.  Xeros develops technology that transforms many water intensive processes by adding polymers to reduce significantly the use of water, chemistry and energy, while improving performance.  Karen’s role at Xeros is to develop its internal sustainability program, as well as helping stakeholders understand the improvements in sustainability and environmental quality provided by using Xeros technology.  Karen is also responsible for internal environmental compliance, and works with customers to insure the adoption of Xeros polymer technology improves their compliance and sustainability.  Karen is part of the Xeros Executive Management Team, which provides leadership for all company verticals.

Karen left private practice after more than 25 years representing manufacturers, contractors and municipalities in matters involving the United States Environmental Protection Agency, the Occupational Safety and Health Administration and equivalent state agencies addressing matters of compliance and enforcement. She was a partner in several law firms, the last of which was New England firm of Verrill Dana LLP.  As an advisor to corporations and individuals she gained extensive experience in addressing the remediation of historic hazardous waste sites under CERCLA, managing hazardous waste process issues pursuant to RCRA, and permit and enforcement actions under the CWA and CAA.  While she loved working with clients in developing, maintaining and defending compliance and environmental management programs, Xeros offered her the opportunity to work with a truly game-changing technology that focuses on preserving clean water and working with non-governmental organizations to provide clean water and sanitation in places where it is most needed.  This opportunity to make a difference on a global scale proved irresistible and Karen is happily immersed in learning the technology and assisting the company in implementing it around the world.

Prior to attending law school, Karen served as a fulltime municipal firefighter and medic, and was recognized by the State of Rhode Island as one of its "First Ten Women" honoring women for achievement in non-traditional jobs. She and her husband Jeff live in Mid-Coast Maine, where they enjoy hiking, gardening, birdwatching and boating.

Howard Kenison

Vice Chair
Howard Kenison
Jones & Keller
Denver, CO

Howard Kenison is a shareholder at Jones & Keller, P.C. in Denver, Colorado where he represents clients in environmental matters before state and federal courts and administrative agencies.  He has practiced environmental law exclusively for over 35 years advising and litigating on behalf of clients on a broad range of environmental issues.  Howard has provided counsel and litigation on cases ranging from NEPA compliance and litigation for large-scale water and transportation projects, wetlands and water quality permitting and defense of enforcement actions, air quality permitting and litigation, Superfund and natural resource damage litigation, hazardous and radioactive waste permitting and litigation as well as environmental due diligence in corporate acquisitions and real estate transactions.  Howard is the former Colorado Deputy Attorney General in charge of Colorado's Superfund Litigation, including the litigation resulting in the clean-up of the Rocky Mountain Arsenal. 

Howard has served on the Section’s Council and as chair of the Governance Committee.  He currently chairs the World Justice Project Task Force and served as one of the Section’s representatives to two World Justice Forums.  He served as Planning Committee Chair of the 44th Spring Conference, the ABA Super conference on Environmental Law.  He chaired the ABA’s former Standing Committee on Environmental Law and the ABA’s Working Group on Environmental Issues and the Rule of Law.  Howard is the Colorado State Chair of the Fellows of the American Bar Foundation.

He is recognized in Chambers USA - America’s Leading Lawyers for Business, Natural Resources & Environment in Colorado and Best Lawyers in America and was Environmental "Lawyer of the Year" in 2016.  Howard received the Outstanding Alumni Award from the University of Denver Sturm College of Law, in 2011 and served as the Distinguished Natural Resources Practitioner-in-Residence at the Sturm College of Law in 2010.  He has also been recognized as a Colorado Super Lawyer and in 2009 was the Attorney of the Year, Law Week Colorado.

Howard received his J.D. from the University of Denver Sturm College of Law and his B.A. from the University of Washington (Seattle).  He is a member of the Colorado Bar and admitted to practice before the United States Court of Appeals for the 10th, 8th and District of Columbia circuits as well as the US District Court for Colorado.

LeRoy Paddock

LeRoy Paddock
George Washington University Law School
Washington, DC

LeRoy (Lee) C. Paddock is associate dean for environmental law studies. He is a member of the ABA Section on Environment, Energy and Resources Council. Prior to coming to GW Law, he was the director of Environmental Legal Studies at Pace University Law School from 2002 to 2007. Dean Paddock has served as a senior consultant for the National Academy of Public Administration on several projects since 1999. He also was a visiting scholar at the Environmental Law Institute between 1999 and 2002, focusing on clean air act, state-federal relationship, and enforcement issues. From 1978 until 1999, Dean Paddock was an assistant attorney general with the Minnesota Attorney General’s Office where he served as director of environmental policy for 13 years, as manager of the Office’s Agriculture and Natural Resources Division and a member of its executive committee. He has served on numerous national panels including the Aspen Institute’s Series on Environment in the 21st Century, and the American National Standard Institute’s ISO 14000 Environmental Management Systems Council.

Dean Paddock graduated from the University of Iowa Law School with high honors and served as a law clerk to Judge Donald Lay of the U.S. Eighth Circuit Court of Appeals. His recent publications include "Keeping Pace with Nanotechnology: A Proposal for a New Approach to Environmental Accountability and Public Involvement," 21 Pace Environmental Law Review 243 (2004) and "Green Governance: Building the Competencies Necessary for Effective Environmental Management," 38 ELR 10609 (September 2008).

Michelle DiffenderferBudget Officer
Michelle Diffenderfer
Lewis Longman & Walker PA
West Palm Beach, FL

Michelle is the President and a Shareholder of Lewis, Longman & Walker, P.A. a Florida environmental and land use law firm, where she began practicing law in 1995. Michelle assists landowners, businesses and governments with the local, state and federal requirements for permitting land development and infrastructure projects. Michelle has written and presented on a variety of topics including wetlands, endangered species, water, National Environmental Policy Act requirements and the ongoing restoration of America’s Everglades.

Michelle has served the American Bar Association's Section of Environment, Energy & Resources in various roles since she first became active in the Section in 2002, including Education Officer, Executive Council, Public Service Task Force Chair, State and Regional Environmental Cooperation Committee Chair, Communications and Marketing Chair, Outreach Chair, and as Liaison to the Florida Bar’s Environmental and Land Use Law Section. Michelle also has worked on, sometimes as Chair, the planning committees for various Section Conferences including, Key Environmental Issues in EPA Region 4, Eastern Water Law, Annual Water Law, Fall, and Spring. Michelle is a Fellow of the American Bar Foundation and the American College of Environmental Lawyers. Michelle is a Past Chair of the Environmental and Land Use Law Section of the Florida Bar.

The Chamber of Commerce of the Palm Beaches recognized Michelle with the ATHENA® Award in 2008 which honors individuals that have achieved professional excellence, actively served the community, and helped women to reach their leadership potential. Michelle has also received The Florida Commission on the Status of Women Florida Achievement Award (2016), the Families First of Palm Beach County Harriet Goldstein Award (2015), the University of Miami School of Law Alumni Achievement Award (2014), the Business Leader Magazine’s Women Extraordinaire Award (2011) and the Caribbean-American Democratic Club of Palm Beach County’s Community Change Maker Award for Environmental Advocacy (2013).  Michelle is AV Preeminent rated by Martindale Hubbell and has also been recognized in her field by several publications including Florida Super Lawyers, Florida Trend Legal Elite, and The International Who’s Who of Environmental Lawyers. Michelle received her Bachelor of Arts, with honors, from Brown University in 1990 and her Juris Doctor, cum laude, Order of the Coif, from the University of Miami, School of Law in 1994.

Michelle and her family enjoy traveling especially when in the company of their beloved ABA friends.


Susan Margaret FloydEducation Officer
Susan Margaret Floyd
Entergy Services, Inc.
New Orleans, LA

Susan Margaret Floyd is a senior (environmental) counsel at Entergy Services, Inc. Floyd's experience includes matters related to natural resource damage assessment under the Oil Pollution Act, regulatory requirements under the Clean Water Act, the Clean Air Act, RCRA, CERCLA and TSCA, including issues associated with citizen suits, and recent initiatives by state and federal agencies, especially in the area of environmental justice. An active member of the American Bar Association, Section of Environment, Energy, and Resources, Floyd served as Program Chair for the 2016 Spring Conference held in Austin, Texas. She has also served as Chair of the Special Committee on Law Students and the Special Committee on State and Local Bar Cooperation. At the state level, Floyd has served as Chair of the Section on National Resources, Energy and Environmental Law of the Mississippi Bar Association. She was recognized in "Chambers USA – America's Leading Lawyers for Business" in the area of Environment as an "Associate to Watch" in 2014 and a "Star Associate" in 2015 and 2016. Floyd was also named a "Rising Star" in the area of Environmental Law in the Mid-South Super Lawyers (listed annually since 2013) and recognized by the Mississippi Business Journal as one of "Mississippi's 50 Leading Business Women for 2014. Floyd received her undergraduate degree at the University of the South in Sewanee, TN, her Masters of Education in Gifted Studies at Mississippi University for Women, and her Juris Doctorate degree from Mississippi College School of Law.

Jeffery S. DennisMembership and Diversity Officer
Jeffery S. Dennis
Advanced Energy Economy
Lorton, VA 

Jeff Dennis is Senior Counsel at Akin Gump Strauss Hauer & Feld LLP in the Washington, DC office. Prior to that he was Director, Division of Policy Development, in the Office of Energy Policy and Innovation at the Federal Energy Regulatory Commission in Washington, D.C. In that role, he leads efforts to evaluate the effectiveness of existing Commission policies and to identify new and emerging policy issues impacting the Commission’s statutory responsibilities.

Previously, Jeff served as a Legal Advisor to Commissioner John R. Norris at FERC, where he provided legal and policy advice to the Commissioner on all aspects of FERC’s regulation of the electricity and natural gas industries. Before joining Commissioner Norris’ staff, Jeff was Director, Federal Regulatory Affairs, at Edison Electric Institute (EEI), the trade association representing investor-owned electric utilities. Earlier in his career, Jeff was an Attorney-Advisor and Appellate Attorney at FERC, where he advised the Commissioners on electricity regulatory matters, and defended the Commission on appeal before the United States Circuit Courts of Appeals. Jeff has also been an attorney in private practice, representing electricity generators and large power users in federal and state regulatory proceedings.

Jeff has held several leadership positions in the ABA Section of Environment, Energy, and Resources, including Young Lawyers Division liaison, committee chair, and member of Council. He is also an active leader in the Energy Bar Association. In addition, he has published several articles in trade and scholarly publications, and is a frequent speaker on topics in energy and environmental law and policy. Jeff has a J.D. from the University of New Mexico School of Law, Order of the Coif, where he earned a certificate in natural resources and environmental law, and a B.A. from Marymount University (Arlington, VA), summa cum laude.

Jonathan W. KahnPublications Officer
Jonathan W. Kahn
Blake Cassels & Graydon LLP
Toronto, ON

Jonathan Kahn is a partner in the Toronto office of Blake, Cassels & Graydon LLP, one of Canada’s leading business law firms. He has for more than 30 years provided representation and advice on a broad range of environmental and natural resources law issues. He routinely represents clients on the purchase, sale, and remediation of contaminated land, mining regulation and permitting; management of natural resources; the transportation, handling and disposal of hazardous substances; environmental permitting; air, water and waste regulation; lender liability; and other environmental matters. Jonathan’s wide-ranging expertise also includes representing accused corporations in significant environmental prosecutions; acting for proponents in major mining, renewable energy and infrastructure projects and providing environmental law advice on a range of significant transactions. Jonathan’s clients span a wide spectrum of industries, including chemical, mining, construction, oil and gas, transportation, general manufacturing, automotive, food and beverage, and agribusiness.

Routinely ranked as a leading environmental lawyer by a range of publications, Jonathan was named global Environmental Lawyer of the Year in 2018 by Who’s Who Legal and was described as “one of the top environmental law practitioners in Canada” by Chambers Global.

Jonathan has served in a variety of leadership positions in SEER. In addition, Jonathan served as Chair of the National Environment, Energy and Resources Law Section of the Canadian Bar Association in 2012-13, and is a former chair of the Environmental Law Section of the Ontario Bar Association.

Pamela E. BarkerSection Delegate to the ABA House of Delegates
Pamela E. Barker
Lewis Rice LLC
Saint Louis, MO

Before joining Lewis Rice, Pam was outside counsel for Appvion, Inc. Prior to that she was the Chief Regulatory and Environmental Counsel and Assistant General Counsel at Appvion Inc., joining the company in February of 2007. Prior to that, she was a shareholder at Godfrey & Kahn S.C., a Milwaukee law firm where she practiced for 27 years. At Godfrey & Kahn she was the co-chair of the Environmental Energy Practice Group. Her primary area of practice was in federal and state environmental law focusing primarily on complex issues arising out of real estate transactions, corporate mergers and acquisitions and lender liability.

Pam has long held leadership positions with the State Bar of Wisconsin and the American Bar Association. In 1993 she was the first woman and youngest President of the State Bar of Wisconsin. Prior to that she served as the Chairperson of the Board of Governors of the State Bar of Wisconsin and was the President of the Milwaukee Young Lawyers Association. Pam served eight years in the House of Delegates of the ABA and served on the Executive Council of the Young Lawyers Division of the ABA. Within the Section of Environment, Energy, and Resources, Pam has served on the Council, as Chair of the Governance Committee, and as Chair of the Environmental Transaction and Brownfields committee. She has also served on many committees within the American Bar Association including the Commission on Women in the Profession.

In 1979 Pam received a Juris Doctorate from the University of Wisconsin Law School, magna cum laude, and received a B.A., cum laude from Beloit College.

Sheila S. HollisSection Delegate to the ABA House of Delegates
Sheila S. Hollis
Duane Morris LLP
Washington, DC

Sheila Slocum Hollis is chair of the Duane Morris, LLP Washington, D.C. office, and was the office's founding managing partner, as well as the founding leader of the firm's Energy, Environment and Resources Practice Group. She served on the firm's Executive Committee and Partners Board for more than a decade.

Ms. Hollis practices in the areas of energy policy, transactional and regulatory law worldwide. She was the founding Director of the Office of Enforcement of the Federal Energy Regulatory Commission. For 20 years, she was adjunct professor at George Washington University Law School, teaching over 600 students energy law and co-authored texts on energy law.

Sheila served as the first woman President of the Energy Bar Association, Chaired the ABA’s Section of Environment, Energy and Resources and serves as its representative in the ABA House of Delegates, chaired the Federal Bar Association’s Energy and Environment Section and multiple other Bar related entities. She Chairs the ABA’s Standing Committee on the Law Library of Congress. She is the recipient of multiple honors and awards and was recognized in 2017 as one of Washington, D.C.’s Top 100 Lawyers in Washington Super Lawyers. Widely published, she is a frequent commentator on environment and energy issues in CNN and other media.

Ms. Hollis is ranked by Chambers and is AV Preeminent for 30 years by Martindale-Hubble. She was named one of the 50 Key Women in Energy Worldwide and received the 2011 Lifetime Achievement in Energy in Platt's Global Energy Awards. She is a Trustee of the Center for American and International Law, a Life Fellow of the American Law Institute and Honorary International member of the Commercial Bar of England and Wales, Ms. Hollis was elected to membership in the American College of Environmental Lawyers. Sheila was recognized for achievement in International Law and Policy by the University of Denver Law School and delivered a major address on international energy law at the award event.

Ms. Hollis serves as a Board Member of the American Friends of the Royal Society, Treasurer of the United States Energy Association, a Trustee of Plimoth Plantation and the Sustainability Advisory board of KB Homes.

Ms. Hollis is a graduate of the University of Colorado at Boulder, Cum Laude in its Honors  Program and with Honors in Journalism. She is a graduate of the University of Denver College of Law and studied at the University of Exeter in England. She is a member of the Colorado and DC Bar Associations and an honorary barrister in the Commercial Bar of England and Wales.  

John E. MilnerImmediate Past Chair
John E. Milner
Brunini Grantham
Jackson, MS

John Milner concentrates his practice primarily in environmental law. He represents business and industrial clients in environmental litigation in state and federal courts in the southeastern region, as well as environmental permitting and enforcement actions, natural resource damage assessments, and regulation promulgation proceedings before the United States Environmental Protection Agency and the Mississippi Department of Environmental Quality and other federal and state agencies. His environmental practice also concerns real estate due diligence and contractual matters in the southeastern region states. John represents clients in lobbying and monitoring activities concerning environmental and other business and industry issues before the Mississippi Legislature.

He is a Fellow in the American College of Environmental Lawyers. He has also been recognized by Woodward/White as one of the Best Lawyers in America® in the fields of Environmental Law and Litigation- Environmental in Mississippi and is ranked by Chambers USA: America’s Leading Lawyers as a Band 1 practitioner of environmental law in Mississippi.

John is the Immediate Past Chair of the ABA Section of Environment, Energy, and Resources, having served as Chair for the 2017 – 2018 Section year. In 2013, at the ABA Annual Meeting, John Milner received from the ABA Section of Environment, Energy, and Resources the first annual “Chair’s Award for Outstanding Contribution” to the Section for 2012-2013.

John currently serves as Environmental Counsel for the Mississippi Manufacturers Association, the primary trade association representing the interests of Mississippi industry, and is General Counsel for the Mississippi Poultry Association and for the Mississippi Petroleum Marketers and Convenience Stores Association. He also serves as a member of the Board of Trustees of the Mississippi Chapter of The Nature Conservancy and is a past Chairman of the Board.