Zachary Fayne focuses primarily on environmental litigation and enforcement matters and regulatory counseling, with a particular focus on issues arising under the Clean Air Act. Mr. Fayne has litigated in both federal and state court. He represents clients in business disputes, class action lawsuits, citizen suit actions, toxic tort litigation, regulatory enforcement matters, challenges to state and federal rulemakings, and natural resource damage claims. Mr. Fayne also counsels clients regarding compliance with air quality regulations promulgated by the US EPA and California Air Resources Board, and has advised and defended numerous companies in connection with California's consumer protection laws.

Mr. Fayne also has an active pro bono practice. Mr. Fayne, together with co-counsel ArchCity Defenders and other Arnold & Porter attorneys, represents a class of individuals in a Section 1983 lawsuit against several St. Louis municipalities alleging that the municipalities engage in unconstitutional debtors' prison practices to coerce payment of unpaid fines from traffic tickets and other minor ordinance violations. Mr. Fayne also has partnered with the Washington Lawyers' Committee for Civil Rights and Urban Affairs in two Section 1983 lawsuits filed in federal district court related to the provision of inadequate medical care at an immigrant detention facility and excessive use of police force, respectively. Both cases resulted in favorable settlements, and Arnold & Porter received an Outstanding Achievement Award from the Washington Lawyers' Committee for its efforts.

Mr. Fayne is a graduate of Harvard Law School, where he served as a Technical Editor of the Harvard Civil Rights-Civil Liberties Law Review. Prior to joining the firm, Mr. Fayne worked at the Public Defender Service for the District of Columbia in the Special Litigation Division.


  • BP as part of a team of attorneys in litigation brought by the United States, citizen and environmental groups, states, and foreign governments arising from the Deepwater Horizon oil spill.
  • Fortune 500 company in litigation in California state court challenging on constitutional grounds the designation of a chemical as a carcinogen under Proposition 65.
  • Electric power company in defense of citizen suit claims under the Clean Air Act.
  • Trade association in litigation challenging a rulemaking by the US EPA and NHTSA setting greenhouse gas and fuel economy standards for heavy-duty trailers.
  • Vehicle manufacturers in litigation challenging a rulemaking by the California Air Resources Board related to onboard diagnostics and recall authority.
  • Hotel owner in breach of contract litigation in Florida state court against hotel management company.


Re-Opening Your Business in a COVID Environment: A Discussion on Protecting Consumers and Employees
Coronavirus: Multipractice Webinar
Cleaning Product Disclosures From Coast to Coast: California Law Goes Into Effect, Is New York Next?
Two-Month Warning: California Cleaning Product Right to Know Act
Navigating the Minefield of State Consumer Product Chemical Disclosure Laws
Overview of California Regulatory Developments
Presenter, Arnold & Porter Webinar for Personal Care Products Council


  • JD, Harvard Law School, 2009, cum laude
  • BA, Washington University in St. Louis, 2006, summa cum laude
  • California
  • District of Columbia
  • Maryland
  • Supreme Court of the United States
  • US District Court, District of Columbia
  • US District Court, Northern District of California
  • Vice Chair, Section on Environment, Energy, and Resources, Air Quality Committee, American Bar Association
  • Member, Advisory Board, OneJustice

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