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Ken Warren

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Ken Warren draws on 35 years of environmental law experience to provide insightful counsel to his clients. His practice includes regulatory, litigation, and transactional matters involving environmental compliance, permitting, environmental aspects of real estate and corporate transactions, site remediations, sustainability and climate change, and alternative energy issues.

Many of the large and small companies that Ken has counseled have benefited from his practical insight and creativity in addressing regulatory and enforcement challenges. Fortune 500 companies have retained Ken to navigate complex federal and state environmental permitting programs. Ken is also a seasoned environmental litigator and has tried numerous cases to verdict. He served as lead trial and appellate counsel for a Fortune 100 company in a multiparty environmental case in which he obtained a favorable final judgment following a lengthy district court trial and successfully defended the judgment on appeal to the Third Circuit. He has also negotiated and helped to administer consent decrees with novel provisions protecting both the companies and the environment.

Ken employs his extensive experience in the field of water resources to advise clients on water supply and allocation, stormwater and wastewater permitting, total maximum daily loads, and safe drinking water compliance. He negotiated a Safe Drinking Water Act Administrative Order on Consent for a Fortune 500 company and assisted the company in implementing the Site remedy through a CERCLA consent decree. He also serves as general counsel for a multistate water resources agency, the Delaware River Basin Commission. This is a rare achievement for an individual in the private sector.

Ken is widely recognized as a leader in environmental law. He is the immediate past-President of the American College of Environmental Lawyers and is listed in leading national and international guides of lawyers for environmental law. He served as Chair of the American Bar Association’s Section of Environment, Energy, and Resources from 2003 to 2004, during which time he led the section’s 10,000 lawyers. He also served as a member of the ABA Standing Committee on Environmental Law and was the initial chair of the ABA’s Homeland Security Task Force. Ken writes a regular column for The Legal Intelligencer on environmental law and has authored numerous articles on environmental issues. He also wrote a chapter in The Law of Environmental Justice. Ken is a frequent speaker on environmental matters before sections of the American Bar Association and other groups.

Ken was appointed by the U.S. Environmental Protection Agency Administrator to serve as an industry stakeholder representative on the EPA’s National Environmental Justice Advisory Council and served on the Council from 2000 to 2006. He served on the Board of Trustees of the Academy of Natural Sciences in Philadelphia, the oldest natural science museum in the Americas.


  • University of Pennsylvania Law School, Philadelphia, Pennsylvania, 1979, JD, magna cum laude, Order of the Coif
  • Brown University, Providence, Rhode Island, 1975, BA, magna cum laude, with Honors


  • The Honorable Joseph L. McGlynn, Jr., United States District Court for the Eastern District of Pennsylvania, 1979 – 1980


  • University of Pennsylvania Law School
    • Law Review
    • Order of the Coif
    • Trial Association Award
    • Keedy Cup Moot Court Winning Team
    • Phi Beta Kappa
  • Who’s Who Legal (Environmental Law)
  • Named a Leader in Environmental Law by Chambers USA: America’s Leading Lawyers for Business
  • Best Lawyers in America, selected as a Best Lawyer in America in Environmental Law
  • Best Lawyers in America, selected as Philadelphia’s 2017 Environmental Law “Lawyer of the Year



      • American College of Environmental Lawyers
      • American Bar Association, Standing Committee on Environmental Law
      • Past Chair, American Bar Association; Section of Environment, Energy, and Resources
      • Pennsylvania Bar Association
      • Delaware Valley Environmental Inn of Court


      • Board of Trustees, The Academy of Natural Sciences
      • Board Member, The Pinchot Institute for Conservation


      • Speaker, “Flowing into the Future: Evolving Water Law Issues,” Pennsylvania Bar Institute, June 2011

Bar Admissions

      • Pennsylvania