Clients rely on Nessa to help them solve their most complicated, expensive, and intractable problems.

Nessa focuses her practice on complex environmental litigation, including multi-district and multi-party litigation, pre-litigation counseling, and administrative litigation. She is a team-oriented leader who works with clients to understand their priorities and operations in order to achieve client-driven outcomes. She also brings a litigator’s eye to pre-litigation opportunities to reduce risk, including pre-litigation counseling regarding the National Environmental Policy Act (NEPA) and emerging contaminants such as PFAS. Given the high profile nature of much of her work, Nessa has experience working with clients’ executive, legal, public relations, and government relations teams to develop comprehensive strategies.

Nessa has led significant trial court and appellate matters, including federal appeals, to a successful conclusion. She has experience with a range of high-stakes litigation, including mass environmental claims, coordinated litigation with federal government entities, class action, and single-party litigation. Nessa also has significant experience with administrative litigation, including multiple rulemaking challenges in various jurisdictions. 

Nessa has achieved favorable results for FORTUNE® 100 companies, states, and counties in federal and state courts throughout the country. She litigates federal and state statutory claims, as well as common law tort claims, with particular experience in product liability and nuisance claims. She has played a leading role in large joint defense groups and in coordinated litigation with federal and state governments, as well as in smaller single-party litigation matters.

Examples of Nessa's experience include:

  • Obtaining a unanimous decision from the D.C. Circuit in a precedent-setting case regarding modification of an injunction under NEPA.
  • Securing summary judgment in the U.S. District Court for the District of Columbia defending the Bureau of Reclamation’s NEPA review of a $250 million water infrastructure project on behalf of the State of North Dakota.
  • Obtaining an injunction of New Hampshire’s maximum contaminant levels for certain PFAS.
  • Serving as one of the lead lawyers on a team defending numerous products liability and toxic tort cases related to alleged groundwater contamination involving a gasoline additive in both federal and state courts, briefing novel issues regarding the scope of a state’s authority to bring claims on behalf of its citizens for the New Hampshire State Supreme Court.
  • Successfully defeating class certification on behalf of an oil refiner client in a proposed statewide class action in federal court against numerous refiners involving alleged damage to boats from certain fuels.
  • Representing a coke plant in a lawsuit alleging Clean Air Act and Resource Conservation and Recovery Act citizen suit claims as well as state common law tort claims.
  • Advising developers of water infrastructure on the NEPA process and issues arising under NEPA (including invasive species), including the preparation of a full Environmental Impact Statement.
  • Denial of class certification in a suit involving 20,000 commercial waste collection customers across Florida, having highlighted significant variation in the underlying contracts.

Nessa currently serves on the firm’s Management Committee and previously served as Chair of the firm’s Diversity, Equity, and Inclusion Committee. She served several terms as the co-chair of the Environmental Law Forum of the Women’s Bar Association of Washington, DC.


  • Emory University  (B.A., magna cum laude, 1998)
    • History, Political Science, and Human and Natural Ecology
  • University of Virginia  (J.D., 2003)

Bar Admissions

  • District of Columbia
  • Virginia
  • Colorado

Court Admissions

  • U.S. Court of Appeals – Fourth Circuit
  • U.S. Court of Appeals - D.C. Circuit
  • U.S. Court of Appeals - Eighth Circuit
  • U.S. District Court – Colorado
  • U.S. District Court – District of Columbia
  • U.S. District Court – Eastern District of Virginia
  • U.S. District Court – Western District of Virginia

Professional Affiliations

  • Fellow, American Bar Foundation

  • 2019 Fellow, Leadership Counsel on Legal Diversity

  • American Bar Association

Honors & Awards

  • Chambers and Partners - USA, Band 5 in Environmental Law (2021-2023)
  • The Best Lawyers in America©, a Best Lawyers® publication, recognition in Environmental Litigation (2015-2024)
  • The Legal 500, recognition in Environmental Litigation (2019-2020)