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California Proposition 65

Our Proposition 65 practice is one of California's largest and most experienced, encompassing lawyers and lobbyists in our San Francisco, Los Angeles and Sacramento offices. Our breadth and depth of experience in advising, defending and advocating for businesses regulated by this unique law are unmatched. Our active practice, which keeps us in regular communication with regulators, activists and plaintiff's counsel, enables us to efficiently serve our diverse clientele and provide cost-effective, valuable insights and services. We have intensively litigated dozens of matters, with leading roles in the majority of major multiparty cases brought over the statute's 30+ years. We often handle cases involving newly emerging legal and scientific issues and lead industry coalitions in challenging regulations and chemical listings.

  • Deep Experience: Three of our attorneys have focused their practices on Proposition 65 for more than 20 years.

  • At the Forefront: We have led defense groups and industry coalitions in litigating—often through appeal—almost every key Proposition 65 issue, from constitutional and regulatory challenges to affirmative defenses.

  • Broad Scope: Our Proposition 65 lawyers have represented thousands of companies, large and small—from suppliers to manufacturers, distributors to retailers—in almost every industry.

“Arnold & Porter adeptly advises on emerging scientific issues, at both a state and federal level [with] a particularly strong track record of advising on matters relating to California's Proposition 65.” – Chambers USA
“They are experts on the subject matter and seek to understand and prioritize what we want to achieve, tailoring the legal strategy to those objectives.” – Chambers USA, Client

Experience Highlights

  • California Chamber of Commerce and Farm Bureau Federation in defending regulatory standard for lead against activist group challenge.
  • McDonald's, Applebee's and other national restaurant systems in defeating claims by animal rights activists that Proposition 65 warnings are required on grilled chicken.
  • The Walt Disney Company in litigation concerning claims of air emissions from engines and defending warning signage.
  • Dunkin' Donuts, 7-Eleven, ampm, and National Coffee Association in long-running litigation over acrylamide in coffee.
  • California Chamber of Commerce in First Amendment challenge to enforcement of warnings for acrylamide.
  • Consumer Brands Association (formerly Grocery Manufacturers Association) on Proposition 65 regulatory and legislative reform issues.
  • Several national retail chains regarding Proposition 65 claims for exposure to phthalates (DEHP, DBP, DINP) in everyday household products, including kitchenware, tools, fashion accessories, and electronic, as well as in Proposition 65 compliance strategies.
  • Kellogg's, General Mills and Post in appellate ruling that warnings for acrylamide in breakfast cereal are preempted by federal law.
  • Three major supplement manufacturers in trial establishing that dietary supplements are covered by the naturally occurring exemption.
  • Two plumbing manufacturers in a successful trial of claims that Proposition 65 prohibits the sale of their products in California (ruling affirmed on appeal).
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Related Services


  • Chambers USA
    Food & Beverages: Regulatory and Litigation (Nationwide) (2023)
    Retail (Nationwide) (2023)