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David G. Mandelbaum represents clients facing problems under the environmental laws and serves as Co-Chair of the firm's Environmental Practice. He regularly represents clients in lawsuits and has also helped clients achieve satisfactory outcomes through regulatory negotiation or private transactions. David teaches Superfund, and Oil and Gas Law in rotation at the Temple Law School. He teaches the Superfund course at Suffolk (Boston) Law School as well. David is a Fellow of the American College of Environmental Lawyers.


  • Air, water and waste regulation
  • Superfund and contamination
  • Climate change 
  • Oil and gas development 
  • Water rights


Esperienze Professionali - Attività Accademiche

  • Represent pesticide manufacturer in litigation over selection of RCRA corrective action for arsenic in soils. FMC Corp. v. NYSDEC, 101 N.E.3d 379 (N.Y. 2018), and related federal and administrative litigation.
  • Represent paper manufacturer in enforcement, cost recovery, natural resources damages, and contribution litigation arising from the Lower Fox River and Green Bay Superfund site.  NCR Corp. v. Geo. A. Whiting Paper Co., No. 2:08-cv-16 (E.D. Wis.); United States v. P. H. Glatfelter Co., No. 2:10-cv-910 (E.D. Wis.).
  • Represent industrial parties in connection with the Sheboygan River and Harbor Superfund site, the Lower Passaic River Site, and scores of other Superfund or contaminated sites.
  • Represent underflowed property owner in connection with claim for diminution in value.  Tri-Realty Co. v. Ursinus College, No. 2:11-cv-5885 (E.D. Pa. consent decree entered Sept. 25, 2017).
  • Represented permittee in third-party appeal of greenhouse gas accounting provisions of air pollution permit for natural gas pipeline compressor station engines). Group Against Smog & Pollution v. Department of Environmental Protection, No. 2012-127-R (Pa. EHB settled June 28, 2013).
  • Represented plaintiff oil, gas and mineral estate holder in action for declaration of rights to access its property in the Allegheny National Forest. Seneca Resources Corp. v. United States Forest Service, No. 1:09-cv-154-SJM (W.D. Pa. Mar. 19, 2013).
  • Represented client on the brief for amicus curiae Business Round Table in public nuisance case by state attorneys general against emitters of greenhouse gases. American Electric Power Co., Inc. v. Connecticut, 564 U.S. 410 (2011).

Riconoscimenti e Premi

  • Listed,The Best Lawyers in America, Environmental Law; Litigation - Environmental; Water Law, 2006-2021
    • "Lawyer of the Year," Environmental Law, Philadelphia, 2015 and 2018
    • "Lawyer of the Year," Litigation - Environmental, Philadelphia, 2016
  • Listed, Chambers USA Guide, 2003-2021
  • Listed, Super Lawyers magazine, Pennsylvania Super Lawyers, 2004-2020
  • Listed, The Legal 500 United States, 2014-2021
    • Environment - Litigation, 2014-2021
    • Environment - Regulatory, 2018-2021
    • Dispute Resolution - Product Liability, Mass Tort and Class Action - Toxic Tort - Defense, 2018-2019, 2021
  • Team Member, The American Lawyer’s “Regional Litigation Department of the Year - Pennsylvania,” Finalist, 2018
  • Listed, Euromoney's Expert Guide to the World’s Leading Experts in Environmental Law, 2017-2021
  • Team Member, U.S. News - Best Lawyers®, Best Law Firms Edition, "Law Firm of the Year," Environmental Law, 2016
  • Selected, National Law Journal magazine, "Energy & Environmental Trailblazer," 2015
  • Listed, International Who's Who of Environmental Lawyers, All Editions
  • Rated, AV Preeminent® 5.0 out of 5.0

°AV®, AV Preeminent®, Martindale-Hubbell DistinguishedSM and Martindale-Hubbell NotableSM are certification marks used under license in accordance with the Martindale-Hubbell® certification procedures, standards and policies.

  • Adjunct Professor, Suffolk University Law School, Environmental Litigation, Spring Semester 2021 
  • Fellow, The American College of Environmental Lawyers, 2020-Present 
  • Adjunct Professor, Temple University James E. Beasley School of Law, Oil and Gas Law, Environmental Law, Superfund Litigation, Global Climate Change Law, 1990-Present
  • Former Member, Delaware Valley Regional Planning Commission, 2007-2011
    • Vice-Chair 2009-2010
  • Vice-Chair and Former Subcommittee Chair, Pennsylvania Statewide Water Resources Committee
  • Member, American Bar Association, Section on Environment, Energy and Resources
    • Past Chair, Special Committee on Smart Growth and Urban Policy
    • Member, Annual Conference on Environmental Law Planning Committee, 2009
  • Member, Maryland State Bar Association, Environmental Section
  • Member, Pennsylvania Bar Association
    • Past Chair, Environmental, Mineral, and Natural Resources Law Section
  • Member, The Florida Bar Association, Environmental and Land Use Law Section
  • Past Chair, Delaware Valley Environmental American Inn of Court
  • Course Planner, Pennsylvania Environmental Law Forum


  • Laurea magistrale in Giurisprudenza, magna cum laude, Harvard Law School, 1983
  • A.B., summa cum laude, Harvard College, 1980
Tirocinio presso una Corte
  • Hon. Louis H. Pollak, U.S. District Court for the Eastern District of Pennsylvania
  • Pennsylvania
  • Florida
  • Maryland
  • Massachusetts
  • Supreme Court of the United States
  • U.S. Court of Appeals for the Fourth Circuit
  • U.S. Court of Appeals for the Second Circuit
  • U.S. Court of Appeals for the Seventh Circuit
  • U.S. Court of Appeals for the Third Circuit
  • U.S. District Court for the Eastern District of Pennsylvania
  • U.S. District Court for the District of Columbia
  • U.S. District Court for the District of Massachusetts
  • U.S. District Court for the Eastern District of Wisconsin
  • U.S. District Court for the Middle District of Florida
  • U.S. District Court for the Middle District of Pennsylvania
  • U.S. District Court for the Western District of New York
  • U.S. District Court for the Western District of Pennsylvania