Allison Rumsey's practice focuses primarily on environmental litigation and enforcement matters. Ms. Rumsey represents clients in State and federal regulatory enforcement actions, class action and citizen suit lawsuits, and business disputes. She represented BP in the litigation brought by the United States, citizen and environmental groups, states, and foreign states arising from the Deepwater Horizon oil spill.

In addition to litigation, Ms. Rumsey advises clients on federal and State regulatory compliance programs. She has experience in CERCLA, RCRA, the Clean Air Act, the Clean Water Act, and the National Environmental Policy Act, among other statutes. Ms. Rumsey also has an active practice representing clients with respect to the environmental laws applicable to large infrastructure and other projects, including the development of a gold mine, the construction of a railroad bridge across a major waterway, and the redevelopment of a large sports field on federal land.

Prior to joining the firm, Ms. Rumsey was Counsel to the Assistant Attorney General, Environment and Natural Resources Division of the US Department of Justice. As an Honors Trial Attorney in the Natural Resources Section, Ms. Rumsey handled several high-profile environmental cases. She was awarded the Distinguished Service Award.

Ms. Rumsey also has worked extensively in South Africa on a variety of environmental issues. In addition, she is an Adjunct Professor at Georgetown University Law Center teaching Environmental Law.

Ms. Rumsey clerked for the Honorable Harold Greene, United States District Court of the District of Columbia and for the Honorable Harry T. Edwards, US Court of Appeals, District of Columbia Circuit.


  • Chemours, as lead counsel, on enforcement litigation brought by the State of North Carolina, relating to the discovery of chemicals in the Cape Fear River in North Carolina attributable to the client's facility.
  • Chemours, as lead counsel, in four toxic tort class action lawsuits brought by homeowners around facility, and public water utilities.
  • BPXP as part of a team in lawsuits brought by the United States under the Clean Water Act and Oil Pollution Act and other actions claiming violations of a variety of federal and state laws, brought as a result of the oil spill by the state of Louisiana, citizen groups, and environmental groups, among others.
  • FORTUNE 100 company in a cost recovery action brought by the United States at Cape Canaveral Air Force Station.
  • FORTUNE 500 company in CERCLA litigation related to the cleanup and redevelopment of shorefront property and the remediation of Hudson River sediments.
  • Major chemical company in a natural resource damages matter arising from historic contamination of the Ottawa River in Toledo, Ohio.
  • Wind developer on a large wind farm in Wyoming.
  • Large oil company as part of a team in negotiations with the US Environmental Protection Agency over alleged Clean Air Act permitting issues at a refinery.
  • FORTUNE 100 company in providing legal counseling on the impact of listings under the Endangered Species Act on a wind farm development.
  • International pulp and paper company on the implications of the new regulatory landscape climate change on their business.
  • FORTUNE 100 company in providing legal assistance both on compliance with federal greenhouse gas regulations, policies, and programs and understanding opportunities created by those new regulations.


Top Read for 2023: Our Recently Published Clean Water Act Essentials Book
Environmental Edge: Climate Change & Regulatory Insights
Two New Hazardous Substances: The Impact of Listing PFOA and PFOS Under the Comprehensive Environmental Response, Compensation, and Liability Act (pdf)
The Journal of Federal Agency Action, Volume 1, Number 1
Clean Water Act Essentials Third Edition
ABA Book Publishing
Two New Hazardous Substances: The Impact of Listing PFOA and PFOS under CERCLA
Biden-Harris EPA Announces Clean Water Act Rule to Re-Empower States and Tribes
Environmental Edge: Climate Change & Regulatory Insights


Green 500: Leaders in Environmental Law—Environmental Litigation (2023)


  • J.D., Georgetown University Law Center, 1992, magna cum laude, Order of the Coif
  • B.A., Middlebury College, 1985, cum laude
  • District of Columbia
  • Colorado
Government & Military Service
  • Honors Trial Attorney, Natural Resources Section, US Department of Justice
  • Counsel to the Assistant Attorney General, Environment and Natural Resources Division, US Department of Justice
  • United States Court of Appeals, District of Columbia Circuit, The Honorable Harry T. Edwards
  • U.S. District Court, District of Columbia, The Honorable Harold H. Greene
  • Adjunct Professor, Environmental Law, Georgetown University Law Center

  • Instructor, Environmental Law Institute Superfund Bootcamp


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