David G. Mandelbaum

David G. Mandelbaum represents clients facing problems under the environmental laws. He regularly represents clients in lawsuits and also has helped clients achieve satisfactory outcomes through regulatory negotiation or private transactions. A fellow of the American College of Environmental Lawyers, David teaches Superfund, and Oil and Gas Law in rotation at the Temple University Beasley School of Law as well as an environmental litigation course at Suffolk (Boston) Law School.

Mr. Mandelbaum has been engaged in matters involving allocation of costs among responsible parties, especially under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). He has tried large cases and resolved others as lead counsel. He has written, spoken, and taught extensively on the subject. He also has been engaged to assist lead counsel from this firm and others:

•to develop cost allocation methodologies;
•to craft expert testimony in support of a favored methodology (given a definition of “fairness,” why one methodology better tracks it than another);
•to develop efficient case management approaches;
•to manage portfolio of contaminated properties and related risks and litigation; and
•to assist private allocation as part of a neutral team.

Mr. Mandelbaum has advised clients on specific compliance and enforcement questions, and broader issues of compliance management systems, sustainability policies, and, more recently, strategies concerning “ESG.” He has been engaged to assist in the development of offshore wind and onshore alternative energy projects as well as the redevelopment of contaminated properties.

Judicial Clerkships

•Hon. Louis H. Pollak, U.S. District Court for the Eastern District of Pennsylvania

Recognition & Leadership

Awards & Accolades

•Honoree, Pennsylvania Bar Association Environmental and Energy Law Section, 'Environmental Law Lifetime Achievement Award,' 2022
•Listed, Chambers USA Guide, 2003-2025 (Band 1 in each edition)
•Listed, The Best Lawyers in America, Environmental Law; Litigation - Environmental; Water Law, 2006-2026
•'Lawyer of the Year,' Litigation - Environmental, Philadelphia, 2016 and 2024
•'Lawyer of the Year,' Environmental Law, Philadelphia, 2015 and 2018
•Listed, Who's Who Legal, 2013-2022
•Thought Leaders - USA, Environment, 2023
•Global Leader, Environment, 2013-2022
•Listed, Euromoney's Expert Guide to the World’s Leading Experts in Environmental Law, 2017-2021
•Listed, The Legal 500 United States, 2014-2025
•Environment - Litigation, 2014-2024
•'Recommended Lawyer,' 2022 and 2024
•'Other Key Lawyer,' 2022 and 2023
•Environment - Regulatory, 2018-2024
•'Other Key Lawyer,' 2022 and 2023
•Dispute Resolution - Product Liability, Mass Tort and Class Action - Toxic Tort - Defense, 2018-2019, 2021, and 2024-2025
•Listed, Boston magazine, 'Top Lawyers - Land Use Environment,' 2022-2023
•Listed, Super Lawyers magazine, Pennsylvania Super Lawyers, 2004-2025
•Team Member, Law360 “Environmental Practice Group of the Year,” 2022
•Team Member, The American Lawyer’s “Regional Litigation Department of the Year - Pennsylvania,” Finalist, 2018
•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
•Rated, AV Preeminent 5.0 out of 5.0