Trial counsel in noted national Superfund cases and toxic tort and environmental insurance coverage litigation, Mark Denehy has successfully represented manufacturers and others in a wide range of complex, high-stakes product liability matters involving asbestos, Silica, DES, radiation exposure, toxic shock litigation and more.

Author of the Toxic Tort Law Desk Reference’s Rhode Island Section, Mark gives his insurance, Superfund and industrial clients informed, connected and accomplished counsel in critical matters that require regional and national management and coordination.

Mark served as Adler Pollock & Sheehan’s Managing Shareholder from 2003–2012 and has won recognition from his peers and professional organizations for his high ethical and legal standards and performance.


  • Suffolk University Law School (J.D., cum laude, 1979)
  • University of Connecticut (B.A., 1975)


  • Rhode Island
  • Massachusetts
  • Connecticut
  • Pennsylvania
  • U.S. District Court, District of Rhode Island
  • U.S. District Court, District of Massachusetts
  • U.S. District Court, District of Connecticut
  • U.S. District Court, Eastern and Western Districts of Pennsylvania
  • U.S. District Court, Eastern and Southern Districts of New York
  • U.S. District Court, South Carolina
  • U.S. Court of Appeals for the First, Third and Fourth Circuits
  • U.S. Supreme Court
Representative Matters
  • Mark served as trial counsel in Violet v. Picillo, one of the leading Superfund cases in the nation.
  • He acted as liaison counsel to 130 defendants in the Davis Landfill Superfund case.
  • He has represented owners, operators, generators, and transporters in numerous Superfund Sites, including
    • the Cannons Engineering Site (Massachusetts and New Hampshire)
    • the Kingston Steel Drum Site (New Hampshire)
    • the Union Chemical Site (Maine)
    • the Western Sand & Gravel Site (Rhode Island)
    • the BestFoods Site (Rhode Island) and
    • the Rose Hill Landfill Site (Rhode Island).
  • Mark has successfully represented numerous industrial clients in litigation against their insurance carriers to obtain coverage for environmental claims.
  • Mark serves as national coordinating counsel for several clients in toxic tort matters.
Seminars / Publications
  • Annually Mark authors the Rhode Island Section of the Toxic Tort Law Desk Reference manual, a 50-state compendium of toxic tort laws.
  • Best Lawyers’ 2022 Lawyer of the Year, Environmental Law, Providence.
  • Best Lawyers 2020 Lawyer of the Year, Mass Tort Litigation / Class Actions – Defendants, Providence.
  • Best Lawyers’ 2019 Lawyer of the Year, Environmental Law, Providence.
  • Best Lawyers’ 2018 Lawyer of the Year, Mass Tort Litigation / Class Actions – Defendants, Providence.
  • Best Lawyers’ 2016 Lawyer of the Year, Products Liability Litigation – Defendants, Providence.
  • AV rated by Martindale-Hubbell, its highest rating for attorneys.
  • Selected by his peers for inclusion in the 2007-2024 editions of The Best Lawyers in America® in the field of commercial litigation, environmental law and mass tort litigation.
  • Recognized in the Chambers USA America’s Leading Business Lawyers in the area of litigation/general and commercial law since 2006.
  • Selected as a Rhode Island Super Lawyer, 2007-2023.


Best Lawyers 2024
Lawyer of the Year
Super Lawyers 2021
Professional Affiliations
  • Member, Rhode Island Bar Association Committee on Environmental Law.
  • American Bar Association’s Torts and Insurance practice section member.
  • Member, ABA’s section on Natural Resources, Energy and Environmental Law.
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