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Margaret E. Peloso

Margaret E. Peloso Partner, Environmental & Natural Resources

Margaret’s areas of practice are environmental law and climate change. With respect to climate change, she handles a variety of matters, including advising on climate change risk management, with a particular emphasis on the changing regulatory environment, and climate change adaptation issues. Margaret works on a variety of complex environmental litigation matters, with a particular focus on issues related to expert witnesses and the use of scientific evidence in litigation. She also deals extensively with the notice and comment process on a wide range of federal environmental regulations.

Prior to joining Vinson & Elkins, Margaret completed her Ph.D. in environment at Duke University, where she wrote her doctoral dissertation on legal and policy issues associated with sea-level rise adaptation. Margaret has authored several articles on climate change and environmental law, and presented papers on a variety of climate change topics at academic and industry conferences, as well as before various federal agency groups exploring climate change adaptation.

Experience Highlights

  • Advising client on EPA’s proposed financial assurance requirements for the hard rock mining industry 
  • Advising client on litigation and expert witness strategy related to one of the Nation’s largest Superfund sediment sites 
  • Advising client on EPA’s rulemaking regarding waters of the United States 
  • Prepared legal analyses regarding CERCLA and common law theories of liability for contaminated sediment sites 
  • Advised manufacturer of industrial explosives regarding potential emission control technologies that could be applied to a new ammonia plant, including analysis of the status of its anhydrous ammonia facility under EPA’s GHG permitting guidance and an assessment of the types of GHG controls that could be selected in a PSD permitting process 
  • Prepared legal analysis and materials for negotiations with EPA regarding adjustment of environmental sampling data 
  • Represented industry trade association in a federal district court challenge by national environmental groups to the U.S. Fish and Wildlife Service’s decision not to list the dunes sagebrush lizard under the Endangered Species Act 
  • Assisted in the preparation of expert witness, depositions of adverse witnesses, and preparation of Daubert motions in soil contamination case
  • Advising global commodities merchant with respect to the creation of procedures for vetting transactions and managing reporting, and on the creation of renewable fuels obligations and trading mechanisms to realize value of renewable fuels credits 
  • Advised downstream energy company in connection with shareholder resolution to defer the purchase of Renewable Fuel Standard (RFS) credits, including guidance on how best to balance obligations under U.S. tax code to maintain status as a MLP while meeting renewable fuels standards 
  • Advising association of U.S. shareholder-owned electric companies regarding EPA's proposed revisions to the Guideline on Air Quality Modeling 
  • Advise clients on legal issues related to climate change adaptation and flood resilience 
  • Advise client on the potential impacts of proposed existing source performance standards, including the potential energy efficiency or emissions reductions measures that may be required in state implementation plans, on client’s assets across the United States 
  • Advising biomass producer regarding implementation of the Clean Power Plan, including comments on EPA’s model trading rules and advice on potential treatment of biomass as carbon neutral 
  • Advised publicly traded energy and services company on a number of complex issues related to acquisition of electric utility, including the impact of the Clean Power Plan on asset valuation and the risks posed by sea-level rise to coastal power plants 
  • Advised private equity firm through bidding and initial contract negotiations for the purchase of a refinery on the West Coast, including drafting contract provisions to ensure compliance with the Renewable Fuel Standards and state cap-and-trade program 
  • Advised biomass producer in response to environmental non-governmental organization (NGO) report alleging inadequate climate change disclosures 
  • Provided environmental and climate change due diligence on transactional matters for the power and chemical manufacturing industries 

Contact Details


T +1.202.639.6774
F +1.202.879.8874
2200 Pennsylvania Avenue NW
Suite 500 West
Washington, DC 20037
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Margaret 's Practices

  • Duke University, Ph.D., Environment, 2010 (Dissertation: Adapting to Rising Sea Levels)
  • Stanford Law School, J.D. with distinction, 2009 (Editor in Chief, Stanford Journal of Law, Science & Policy; Article Review Board Chair, Stanford Environmental Law Journal)
  • Duke University, Masters of Environmental Management, Environmental Economics and Policy; Coastal Environmental Management, 2006
  • Duke University, B.S., Biology summa cum laude, 2005 (Phi Beta Kappa)
  • Admitted to practice: New York; District of Columbia
  • Other language: Conversational in Spanish
  • Law360, Rising Star, 2019
  • Chambers USA, Climate Change (Nationwide), 2015–2019; Star Associate in Climate Change (Nationwide), 2016 and 2017; Up and Coming in Climate Change (Nationwide), 2018 and 2019; Environment (District of Columbia), 2018 and 2019; Associate to Watch in Environment (District of Columbia), 2016 and 2017; Up and Coming in Environment (District of Columbia), 2018 and 2019
  • American Bar Association On the Rise – Top 40 Young Lawyer, 2017
  • Selected to the Washington, D.C. Rising Stars list, Super Lawyers (Thomson Reuters), 2019
  • Legal 500 U.S., Environment: Litigation, 2019; Environment: Regulatory, 2019
    • American Bar Association
      • Section Council: Section of Environment, Energy and Resources (2017-2020)
      • Chair: Section of Environment, Energy and Resources 46th Spring Conference (2017)
      • Chair: Special Committee on Public Service of the American Bar Association’s Section of Environment, Energy, and Resources
      • Chair: Climate Change Sustainable Development and Ecosystems Committee (2012–2014)
    • Member: Law360 Environmental Editorial Advisory Board (2013-2014)
    • Board Member: Women’s Energy Network, Washington, D.C. Chapter (2014-2016)
    • Member: Women’s Energy Network, National Advisory Council