Picture of Mark A. Marionneaux

Mark A. Marionneaux


Mark Marionneaux is a partner in the Baton Rouge office of Kean Miller. He joined the firm in 1994 and practices in the products liability, litigation and toxic tort defense groups. Mark represents some of Louisiana’s most prominent chemical, fertilizer, and energy companies in a wide variety of litigation matters involving chemical exposure, toxic tort, products liability, insurance defense, workers compensation and class action litigation. Mark has over 30 years of experience and regularly advises clients on litigation strategy, insurance coverage issues, and litigation management. He has particular experience in the fertilizer manufacturing, farming and agribusiness industries. Mark is AV-rated by Martindale Hubbell. He also serves as an Assistant Examiner for the Committee on Bar Admissions for the State of Louisiana. Mark was named a BTI Client Service All-Star for 2014 based on independent feedback from corporate counsel. He is listed in The Best Lawyers in America (Litigation – Environmental, Mass Tort Litigation / Class Actions – Defendants) for 2023-2024.

Representative Experience
  • Representation of a national farm chemicals company in trucking related accidents involving spray rigs, specialty farming equipment, and Killbrew trailers
  • Representation of a worldwide chemical refiner in complex insurance coverage litigation related to its Louisiana operations
  • Louisiana counsel for a major fertilizer producer in complex occupational exposure litigation and litigation management
  • Louisiana counsel for a global fertilizer company and with regard to legal challenges arising out of facility operations, product transportation, and manufacturing processes
  • Representation of a large agricultural chemical company with regard to transport of chemicals and in litigation involving its alleged product liability
  • Representation of an energy producer in a wide variety of litigation in connection with its ongoing and legacy oilfield operations
  • Louisiana counsel for large manufacturer of consumer products with regard to products liability claims in Louisiana

Mark earned his B.S. in Criminal Justice from Louisiana State University in 1989. He earned his J.D. in 1992 from the LSU Law Center where he was a member of the Louisiana Law Review.

  • Admitted, Louisiana, 1992; United States District Courts for the Eastern, Middle and Western Districts of Louisiana; United States Court of Appeals, Fifth Circuit; United States Supreme Court
  • Baton Rouge, Louisiana State and American Bar Associations; Louisiana Association of Defense Counsel; Defense Research Institute; 18th Judicial District Court Bar Association
Articles, Publications and Presentations
  • Comment, International Scope of Fourth Amendment Protections: United States v. Verdugo-Urquidez, 52 Louisiana Law Review 455.
  • Comment, The Louisiana Lottery—Supreme Court Style: A Look at State v. Simpson and its Constitutional Mandate of Random Allotment of Criminal Court Cases Within a District, 52 Louisiana Law Review 1285.
Community Service
  • Past Chairman, Workplace Giving Chairman, Capital Area United Way