Keith Casto focuses his practice on energy and environmental regulatory and transactional consultation, environmental and toxic tort litigation, and white-collar environmental criminal defense. His energy and environmental law expertise stems from his ten years of practice in the U.S. Environmental Protection Agency’s (EPA) Region 4 office in Atlanta and over 20 years in private practice in California and Georgia. Keith has extensive experience in conventional and renewable energy projects, greenhouse gas emissions credit trading, green technology financing, and renewable energy project development and is an international speaker on these issues. His privacy and cybersecurity practice embraces both counseling and litigation. He has been recognized in The Best Lawyers in America (BL Rankings) in the field of Environmental Law every year since 2011.

Keith has experience in conventional and renewable energy project financing, entitlements, and regulatory compliance. His environmental regulatory and litigation practice includes regulatory compliance counseling for all environmental media; due diligence investigation in real estate transactions and corporate mergers and acquisitions; domestic and international environmental audits; environmental management system consultation; and civil litigation, including cost recovery for soil and groundwater contamination under Superfund and various common law theories and toxic tort defense. In addition, Keith represents industrial clients, real estate developers, and individuals in defense of civil enforcement actions and criminal prosecutions at federal, state, and local levels in California and throughout the United States.

He has practiced extensively before many energy and environmental agencies throughout California, the United States, and Europe, including the EPA, U.S. Department of Justice, Federal Energy Regulatory Commission, California Public Utilities Commission, California Energy Commission, Bay Area Air Quality Management District and Regional Water Quality Control Boards, U.S. Army  Corps of Engineers, San Francisco Bay Conservation and Development Commission, State Water Resources Control Board, California Air Resources Board, California Department of Toxic Substances Control, and numerous hazardous material management regulatory agencies and water districts.

Professional & Civic Engagement


  • American Bar Association, Environment, Energy, and Resources Law Section and International Law Section
  • State Bar of California, Environmental Legislation Subcommittee 
  • California Lawyers Association, Environmental Law Section (2018 – Present)
  • Environmental Law Institute
  • Bar Association of San Francisco
  • Santa Clara County Bar Association
  • The Florida Bar, Environmental and Land Use Law Section
  • State Bar of Georgia, Environmental Law Section

Community Involvement

  • Bay Area Council, Board of Directors (2009 – 2013)
  • United Way of Silicon Valley, Advisory Board

Thought Leadership


  • “California Air Resources Board Approves Amendments to California’s Climate Change Cap-and-Trade Regulation and Adds New Carbon Offset Protocol,” Client Alert, April 2014
  • “Northern District Issues New ESI Guidelines,” Client Alert, December 2012
  • “California Low Carbon Fuel Standard Case Heard by Ninth Circuit,” Client Alert, November 2012


  • “WCI Carbon Market 2040 Crystal Ball,” Webinar hosted by California Carbon, March 2021

Honors & Awards

  • Recognized in The Best Lawyers in America (BL Rankings), Environmental Law (2011 – Present)