William Voth concentrates his practice on mass tort, consumer, fraud, and product liability litigation. Cases include defense of False Claims Act suits, medical monitoring claims, class actions and other aggregate litigation, governmental cost-recovery suits, public nuisance claims, market share, conspiracy, concert of action, and other industry-wide liability theories. As examples of such representations, he has represented clients in False Claims Act litigation, defended governmental and private claims of injury from lead products in paint in federal and state courts throughout the country, and served as legal issues counsel at trials of Engle progeny tobacco cases in Florida state courts.

Pro bono work includes constitutional challenge to indigent defense system in Mississippi Supreme Court, death penalty appeal in Georgia Supreme Court, and representation of charter school parents.


  • False Claims Act lawsuit against government computer services contractor by US Attorney for the Southern District of New York and New York Attorney General.
  • Defense trial verdicts in governmental lead paint public nuisance suits in California and Rhode Island and in individual personal injury suit in Wisconsin.
  • Legal issues counsel at Engle progeny tobacco trials in Florida.
  • Class certification denials in consumer protection act, economic injury, property damage, and medical monitoring cases in multiple jurisdictions.
  • Summary judgment on conspiracy and other industry-wide liability theories in multidistrict welding products occupational exposure cases against former manufacturers and corporate successors.

  • Dismissal of multiple New Jersey city/county environmental contamination suits seeking abatement and funding of government programs, affirmed in New Jersey Supreme Court.
  • Dismissal of suits by Ohio Attorney General and Ohio municipalities seeking housing abatement and health care expenditures.
  • Pro bono trial and appellate counsel in challenge to Mississippi state criminal indigent defense system.
  • Pro bono counsel for Bronx charter school and parents opposing motion to preliminarily enjoin co-location in underutilized public school building.


False Claims Act Materiality Standard Applied to Dismiss Implied Certification Claims (pdf)
Government Contracting Law Report, Vol. 3, No. 7
Effort to Revive Dismissed Implied Certification Claims Based on Escobar Fails on Materiality Grounds
The Current Enforcement Environment Facing the Financial Services Industry: FCA and FIRREA Liability
Arnold & Porter Regulatory Roundtable, New York, NY
Four Things Every In-House Counsel Should Know About Economic Injury Class Actions
Arnold & Porter LLP
Defending Attorneys General Suits: Current Issues And Perspectives

Arnold & Porter LLP Webinar


The Legal 500 US
Product Liability and Mass Tort Defense: Toxic Tort (2013)


  • JD, Harvard Law School, 1980, cum laude
  • BA, Beloit College, 1977
  • New York
  • Florida
  • US Court of Appeals for the Second Circuit
  • US District Court, Eastern District of New York
  • US District Court, Southern District of New York

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