Deborah C. Prosser

(213) 312-4005
(213) 312-4001 Fax

Ms. Prosser manages national litigation and serves as a first-chair trial lawyer. She focuses her practice on the defense of high-profile toxic tort, environmental, pharmaceutical, products liability and commercial cases.

In the area of toxic tort, pharmaceutical and products liability defense, Ms. Prosser’s experience includes representing clients with diversified products ranging from chemicals (benzene, asbestos, silica, adhesives, solvents, industrial premises and silicones), to engines (locomotive, jet engine, construction equipment), to pharmaceuticals (contrast agents), to medical devices (operating room equipment), to agricultural (pesticides and fertilizers), to military equipment, to industrial products (natural gas compressors) and residential appliances (stoves, refrigerators, dryers).

In the area of environmental law, Ms. Prosser has defended private and public entity clients who were target defendants in a mass tort neighborhood suit alleging soil and groundwater contamination, property damages and medical monitoring, and has also handled numerous CERCLA cases involving large-scale contamination sites for both public and private entities.

Ms. Prosser is a seasoned and creative trial strategist with an established track record of identifying her clients’ goals, mastering complex expert issues, discrediting her opponents’ liability theories, and executing an “exit strategy” by jury verdict, mediation resolution or arbitration award—depending on the unique aspects of each case.

Ms. Prosser serves as the Vice Chair of Publications for the Toxic and Hazardous Substances Litigation Committee of the International Association of Defense Counsel (IADC). She is the Past Chair of the Toxic Torts & Environmental Law Committee of the American Bar Association (ABA) TIPS Section.

  • National coordinating counsel in asbestos litigation for Fortune 100 company involving industrial premises, products and coke oven plants.
  • Lead defense counsel for Fortune 10 company in California Judicial Council Coordinated Proceeding No. 4546 involving mass tort claims for exposure to gadolinium-based contrast agents.
  • Lead counsel for international real estate company on contaminated site in Vernon, California.
  • Commercial arbitration award in favor of aviation company involving claims of $30 million in damages for interior retrofit of Boeing Business Jet.
  • Verdict in favor of public entity client in code enforcement trial involving 40-year dispute over unlawful subdivision of residential apartment units.
  • Verdict in favor of commercial manufacturer for breach of contract and fraud against a vendor of defective component parts for vehicle natural gas cylinders.
  • Over 50 defense verdicts in mass tort trials in Lockheed Litigation involving claims of exposure to industrial adhesives used at Lockheed Skunk Works facility in Burbank, California.
  • Coordinating counsel for benzene cases across the United States.


  • “Discrediting the Opinions of Plaintiffs’ Epidemiologists: Skills and Practice Pointers for Toxic Tort Defense Attorneys,” International Association of Defense Counsel Webinar - December 2015.
  • “Current Perspectives on National Toxic Tort Litigation,” In-House Insurance Company Mass Tort Department Legal Forum, Chicago, IL October, 2015.
  • “The Shield and The Sword: Using Corporate Witness Depositions to Strengthen Your Case,” In-House Corporate Legal Department Forum, Memphis. TN May 2015.
  • “Lender and Lessor Liability," Equipment Leasing and Finance Association Legal Forum - Nashville, TN May, 2015.
  • “Defending Against Brand Attacks,” Corporate Counsel College of the International Association of Defense Counsel - Chicago IL April, 2015.
  • Kutak Rock/Association of Corporate Counsel CLE Program Speaker, “The Ethical Issues Involved with Document Retention for Litigation” - May 2012.
  • Pincus CLE Program Speaker, “How to Cross Examine Expert Witnesses” - October 2011.