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Ed McTiernan has over 35-years of experience as an environmental litigator who focuses on state and federal regulatory issues including site remediation, Brownfield redevelopment, natural resource damages, energy and infrastructure projects, as well as environmental permitting and due diligence. Between 2011 and 2015, Mr. McTiernan was in the Office of General counsel at the New York State Department of Environmental Conservation where he served as Deputy Commissioner and General Counsel. In that capacity, he was responsible for enforcement, rulemaking, and major policy initiatives, including the review and permitting of transportation and energy projects, Article 78 proceedings challenging agency action, as well as citizen action suits, CERCLA cost recovery claims and permit proceedings. Mr. McTiernan supervised a team of 90 attorneys in nine regional offices, and coordinated with federal agencies and national environmental advocacy groups on a number of controversial projects. In addition, he directly supervised the state's docket of environmental litigation, enforcement proceedings, and policy initiatives. Since joining Arnold & Porter he has represented clients in state and federal courts and before administrative bodies on a wide range of matters under the Clean Water Act and Oil Pollution Control Act, federal and state Superfund programs, emerging contaminants, and the National Environmental Policy Act, as well as the New York Environmental Quality Review Act.

Prior to his public service, Mr. McTiernan was in private practice for more than two decades. He also served as a team leader for a New York/New Jersey regional law firm's environmental practice where he represented Fortune 100 corporations and multi-nationals in state and federal court. Representative assignments included defending clients in administrative proceedings and litigation in numerous site remediation matters; serving as special litigation counsel to the New Jersey Meadowlands Commission in connection with the condemnation and remediation of an orphan landfill; appearing before the New Jersey Supreme Court in connection with an appeal of remediation standards; assisting the American Bakeries Association negotiate a nationwide Clean Air Act partnership program with USEPA.. He has also served as a private mediator in environmental disputes.


Best Lawyers
Environmental Law (NY) (2011, 2021-2024)
Natural Resources Law (NY) (2011, 2021-2024)
Litigation: Environmental (NY) (2021-2024)
"Lawyer of the Year" — Environmental Law (New York)
Chambers USA
Environment (NY) (2006-2011, 2023)
The Legal 500 US
Environment: Regulatory (2016-2017)



  • J.D., Seton Hall University School of Law, 1987
  • M.S., State University of New York College of Environmental Science and Forestry, 1980
  • B.S., Biology, Fordham University, 1978


  • New York
  • New Jersey
  • U.S. Court of Appeals for the Third Circuit
  • U.S. District Court, District of New Jersey
  • U.S. District Court, Southern District of New York
  • U.S. District Court, Eastern District of New York
  • U.S. District Court, Western District of New York

Government & Military Service

  • Deputy Commissioner and General Counsel, New York State Department of Environmental Conservation


  • Past Chair, Environmental Section of the New Jersey State Bar Association
  • New York State Bar Association/Environmental Committee, Member Executive Committee, 2012 - 2022; Member, 1987 - Present
  • Fellow, American College of Environmental Lawyers,  2015-2021