Geoff Yost


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Geoff brings more than 25 years of experience to his litigation practice, which focuses on environmental and commercial disputes from the investigation stage through settlement, trial, and appeal. He has represented clients in hazardous waste enforcement, cleanup disputes, environmental citizen suits, and water and other natural resources matters. He is one of only a handful of California lawyers who have taken state hazardous waste “dumpster diving” investigations to court. Geoff has also litigated complex antitrust, patent, and trade secret cases in federal and state trial and appellate courts. He is a member of the firm’s General Litigation and Energy, Natural Resources, and Environment practices

Geoff’s clients span a wide range of industries and include retailers, health care companies, real estate developers and trusts, semiconductor manufacturers and related technology companies, transportation companies, utilities, startups, and consumer products manufacturers.


Honors & Awards

  • Recognized by Best Lawyers® for Litigation - Environmental in San Francisco, CA (2023-2024); Geoff has been listed in Best Lawyers® since 2023
  • Recommended by The Legal 500 US for State Attorneys General (2023)


Bar Admissions

  • California

Court Admissions

  • U.S. District Court, Eastern, Northern, and Southern Districts of California
  • U.S. Court of Appeals, Ninth Circuit
  • U.S. Court of Federal Claims


  • Santa Clara University School of Law, J.D., 1991: cum laude; Emery Scholar
  • University of California at Berkeley, B.A., 1987

Professional Activities


  • California Supreme Court (1990)


  • San Francisco Bar Association

Adjunct Professor

  • University of California, Hastings College of Law (1998)

Editorial Board

  • Environmental Liability, Enforcement and Penalties Reporter (2000-2008)
  • Successfully litigated the termination of a hazardous waste injunction against a major retailer
  • Litigated and settled state hazardous waste enforcement action against a major transportation company
  • Litigated and negotiated with prosecutors in a number of California hazardous and medical waste enforcement investigations
  • Defended real estate developers and manufacturers in toxic tort and environmental contamination litigation
  • Litigated numerous federal and state law cost recovery lawsuits in federal and state courts on behalf of landowners, manufacturers, a major railroad, and energy companies