Peter Hsiao

Attorney in Los Angeles, CA

Peter Hsiao is head of the Environment and Energy Group in Los Angeles and head of the Green Products and Chemicals team. Drawing upon his technical background as a chemical engineer, Mr. Hsiao has 28 years of experience in complex litigation and transactional work with a specialty as a lead trial attorney in environmental, natural resources, chemical toxic tort, and land use law.

Mr. Hsiao is recognized as one of the leading attorneys in environmental law. He is one of 16 lawyers named as a Distinguished Environmental Advocate by the American Bar Association. He was appointed to the ABA's Standing Committee on Environmental Law and is the former Chair of the State Bar of California's Environmental Law Section. Mr. Hsiao is named by Best Lawyers in America as a leading lawyer in environmental law, and by Chambers and Partners as one of the best environmental lawyers. Legal 500 and PLC Global 3000 recommend him as one of the best environmental lawyers in the United States. The International Who's Who of Business Lawyers named him as a leading cross-border environmental attorney. He is listed by Super Lawyers as one of the leading environmental lawyers in California. The Los Angeles Business Journal named him as one of the top environmental lawyers in Los Angeles.

Mr. Hsiao served as a senior trial lawyer for the U.S. Department of Justice as an Assistant U.S. Attorney for the Central District of California. He was lead trial counsel representing the U.S. Environmental Protection Agency and other federal agencies in major environmental and chemical litigation. Mr. Hsiao obtained several multi-million dollar judgments, including the second-largest penalty for violation of the volatile organic compound limitations for consumer and industrial coatings, the largest recovery for cleanup of soil and groundwater pollution, and the then largest penalty for violation of EPA's administrative order authority.

Mr. Hsiao received the U.S. Department of Justice's Special Commendation Award, the U.S. Attorney's Office Special Achievement Award, and the U.S. Fish and Wildlife Service Golden Eagle Award. He was selected to lecture at the Justice Department's trial practice institute on trial practice in environmental cases. He has litigated cases in the U.S. Supreme Court, the federal courts of appeals, and the district and state courts. He also was appointed as a judge pro tem for the Los Angeles Municipal Court and has served as a mediator for environmental cases.

In private practice, Mr. Hsiao is an environmental trial attorney who advises Fortune 500 clients on a wide variety of complex environmental and land use matters. His cases include some of the largest environmental cases in California, including the cleanup of the San Francisco International Airport and the air pollution control measures for the Owens Dry Lake bed, the largest source of particulate air emissions in the United States. He represents clients in multi-party groundwater and soil contamination cases, hazardous waste management and disposal issues, and in Clean Air Act matters. He further advises both public and private clients on the state's complex environmental assessment and land use planning requirements, and litigates cases under CEQA and NEPA.

Mr. Hsiao is the co-editor and co-author of the California Environmental and Natural Resources Law Handbook, a comprehensive treatise now in its 12th edition. He serves as a lecturer for the American Law Institute and the American Bar Association on expert witness testimony and litigation skills in chemical cases. He also has spoken and written widely on the subject of chemical regulation and litigation.

Mr. Hsiao currently serves as senior vice president and is on the executive committee of the board of directors of the Los Angeles County Bar Foundation.

Mr. Hsiao is a magna cum laude graduate in chemical engineering from the University of Utah, where he received the Outstanding Student Award from the American Institute of Chemical Engineers. He obtained his J.D. in 1985 from the Boalt Hall School of Law, University of California at Berkeley, where he received the McBaine Advocacy Award.


Peter Hsiao is recommended as a leading environmental lawyer by Chambers USA 2013, Best Lawyer in America (2011 - 2013), Legal 500 US (2007 - 2013), Los Angeles Business Journal, Los Angeles Magazine and Super Lawyers (2005 - 2013).

(213) 892-5731
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Areas of Law

  • Environmental Litigation
  • Environmental Regulation
  • Clean Technology & Alternative Energy
  • Advanced Chemicals & Materials
  • Proposition 65 & Chemicals
  • Product Liability
  • Land Use & Development
  • Consumer Products
  • Environment & Energy
  • Government & Public Agencies
  • Retail
  • Transportation
  • Green Marketing & Advertising
  • Natural Resources


Peer Rating


Overall Peer Rating

4.4 out of 5.0
  • Meets very high criteria of general ethical standards
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Experience & Credentials



Admission Details

Admitted in 1985, California

Law School Attended

University of California, Berkeley, School of Law
Class of 1985

University Attended

University of Utah
Class of 1982

Contact Information


(213) 892-5731


Send email to Peter Hsiao

Office Information
Peter Hsiao
 707 Wilshire Boulevard,
Los Angeles, CA 90017-3543


Morrison & Foerster LLP (Los Angeles, California)

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