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Jeremy Karpatkin represents technology, consumer products, and chemical companies in a wide range of complex litigation and regulatory matters concerning CERCLA, the Clean Water Act, state environmental laws, FIFRA, and other environmental laws. Mr. Karpatkin has litigated extensively in federal court and represents clients before state and federal agencies. He also counsels clients on federal and state rulemaking and on regulatory compliance. He has successfully challenged EPA rulemakings in federal court, has defended clients in RCRA citizen suits, and has engaged in successful collaboration with state and federal agencies in environmental rulemaking and technically complex compliance matters.

Mr. Karpatkin also has an active constitutional rights pro bono practice. His pro-bono matters include litigation challenging state restrictions on the right to vote under the Voting Rights Act and the 14th amendment, litigating due process claims on behalf of displaced tenants, litigation challenging the termination of the DACA program, and co-authoring amicus briefs to the US Supreme Court on right to counsel, right to education, freedom of speech and freedom of association claims.

Prior to joining Arnold & Porter, Mr. Karpatkin worked at the United States Department of Energy in a variety of capacities involving the remediation of the DOE nuclear weapons complex. His positions included serving as Senior Policy Advisor to the Assistant Secretary for Environmental Management and Senior Advisor to the Manager of the Rocky Flats facility in Golden, Colorado. Previously, Mr. Karpatkin served as Chief of Staff to US Senator Paul Simon.


  • Fortune 100 company on CERCLA clean-ups of sediment "mega-sites" in New Jersey and New York. Representation includes litigation and all stages of the CERCLA remedial process and advising the client on all phases of the equitable allocation process.
  • Fortune 100 company on major redevelopment and remediation project, which successfully transformed a contaminated site into a mixed-use redevelopment area, in partnership with the community and local governments.
  • Fortune 100 company in Special Master process overseeing remediation of contaminated sites in New Jersey subject to federal court consent order, which includes complying with state requirements, federal consent decree requirements and advising the client on property redevelopment.
  • Fortune 500 chemical company in negotiating and resolving with EPA selection and implementation of a remediation remedy under CERCLA.
  • Fortune 100 company on development of federal infrastructure initiatives and implications for environmental requirements and approvals.
  • Advising clients on developing remediation plans during COVID-19, and negotiating agreements with state and federal regulators under CERCLA and state environmental laws
  • Mosaic Fertilizer LLC in successful challenge to EPA water quality criteria, resulting in striking of portion of EPA rule as arbitrary and capricious. Florida Wildlife Federation v. Jackson, 853 F. Supp.2d 1138 (N.D. Fla. 2012).
  • Fortune 100 company in successfully negotiating settlement for cost contribution at contaminated midwestern industrial site.
  • Reckitt Benckiser LLC in complex challenge to EPA FIFRA action in federal District Court Reckitt Benckiser v. Jackson, 762 F. Supp. 2d 34 (D.D.C. 2011), and the Court of Appeals, Reckitt Benckiser Inc. v. EPA, 613 F.3d 1131 (D.C. Cir. 2010); as well as representing Reckitt Benckiser before EPA in FIFRA administrative proceedings.
  • Fortune 100 technology company in RCRA citizen-suit involving contaminated site in Maryland.
  • Major oil and gas company on compliance with EPA Greenhouse Gas Reporting Rule.



Chambers USA
Environment (DC) (2022-20023)



  • J.D., University of Denver Sturm College of Law, 2005,

    Order of St. Ives

  • B.A., Oberlin College


  • District of Columbia
  • Pennsylvania
  • U.S. Court of Appeals for the Eleventh Circuit
  • U.S. District Court, Northern District of Florida
  • U.S. District Court, District of New Jersey

Government & Military Service

  • Senior Advisor, Assistant Secretary for Environmental Management, US Department of Energy

  • Senior Policy Advisor, Office of the Manager, Rocky Flats Field Office, US Department of Energy
  • Chief of Staff, US Senator Paul Simon


  • U.S. District Court, District of Colorado, The Honorable Lewis T. Babcock