Arnold & Porter's Environmental group offers clients access to leading practitioners in every area of environmental law.

We handle precedent-setting legal challenges across the country, in state and federal courts and at the appellate level. As one distinctive example, the firm has been BP's primary environmental counsel in connection with the Deepwater Horizon Gulf of Mexico oil spill; one of the most complex, multi-party legal proceedings in the history of environmental law.

Our practice spans:

  • Litigation and Enforcement: We have a wealth of experience in civil and criminal enforcement under every federal statute; contaminated site cleanups, litigation and related proceedings; catastrophic incident defense and crisis management; and toxic tort claims associated with a diverse array of groundwater, air pollution, toxic chemical, radioactivity, and public nuisance matters.
  • Regulatory: We advise clients on their compliance obligations under the full range of environmental requirements, assist in developing company compliance programs, counsel on risk mitigation measures, identify and manage product supply chain issues, and obtain environmental permits and approvals for controversial projects.
  • Transactional: We manage environmental assessments, negotiate contractual provisions, and negotiate land use permitting for complex development projects. We also advise on the environmental aspects of multijurisdictional business transactions.

Members of the team have served in senior government positions such as Deputy General Counsel, EPA, and EPA leadership roles involving the Clean Air Act, TSCA, and FIFRA; Chief of the Environmental Enforcement Section, DOJ; Honors Trial Attorneys, DOJ; and Deputy Commissioner and General Counsel, NY State Dept. of Environmental Conservation; as well as the current Director of the Sabin Center for Climate Change Law.

» Chart on US Climate Change Litigation

» Read and download a comprehensive guide to NRD programs in all 50 states and Puerto Rico


BP Historic settlement of Deepwater Horizon claims

Negotiated the consent decree to settle all federal and state environmental claims related to the Deepwater Horizon oil spill.

The Mosaic Company Settlement of major EPA enforcement action

Successfully negotiated a complex settlement of RCRA action.

Honeywell Baker et al. v. Saint Gobain Performance Plastics Corp. et al.

Lead toxic tort counsel in class action and toxic tort suits in Hoosick Falls, NY.

Honeywell New York/New Jersey Waterways

CERCLA remedial investigations at numerous sites in the New York/New Jersey waterways.

Atlantic Richfield Nuclear disposal site

Remediation of nuclear disposal site.



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Chambers USA
Environment (Nationwide, DC, California) (2019)
Shortlist – Awards for Excellence in Environment (including Climate Change) (2019)
The Legal 500 US
Environment: Litigation (2019)
Environment: Regulatory (2019)
U.S. News & World Report and Best Lawyers
"Best Law Firms" – Environmental Law (2020)
"Best Law Firms" – Environmental Litigation (2020)
"Law Firm of the Year" – Litigation: Environmental (2015)

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