Shannon M. Kasley Partner

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Shannon has nearly 30 years of experience representing multinational companies in all phases of high-stakes commercial and civil litigation and appeals, appearing before trial and appellate courts, administrative bodies and arbitration panels throughout the country. He regularly advises energy and oil and gas companies in multiparty and multidistrict litigation, including commercial disputes; fraud claims; large chemical dockets; product liability, mass tort and environmental cases; sensitive environmental, social and governance (ESG) issues; antitrust matters; and challenges to regulatory and administrative actions.

In addition, Shannon represents manufacturing and other clients in civil and criminal matters in cases ranging from complex mass tort and antitrust matters to qui tam suits alleging violations of the False Claims Act; securities and consumer fraud class actions; breach of fiduciary duty; breach of contract; unjust enrichment; indemnification; tortious interference; and misappropriation of trade secrets claims. He has counseled corporate clients and individuals in criminal investigations conducted by the Department of Justice, the Securities and Exchange Commission, the Internal Revenue Service, the Office of the Comptroller of the Currency, the Federal Bureau of Investigation, and U.S. Army Criminal Investigation Command, as well as by numerous state attorneys general. In particular, Shannon has advised banking and oil and gas clients in connection with antitrust cartel matters, including internal investigations, leniency applications, and responding to grand jury subpoenas.

Early in his career, Shannon served as a law clerk to the Hon. Garrett E. Brown, Jr., United States District Judge and later the Chief Judge of the U.S. District Court for the District of New Jersey. Before law school, he played semi-professional baseball in New Jersey.


  • Currently lead counsel for an international oil and gas company in connection with responses to a state AG subpoena concerning an alleged “forever chemical.”
  • Currently co-lead counsel for an international oil and gas company in connection with advice concerning the company’s legacy product catalog and related chemicals.
  • Currently co-lead counsel for an international oil and gas company in several suits that uncovered a fraudulent kickback scheme at one of the company’s refineries and has resulted in the recovery of over $7 million from those involved.
  • Co-lead counsel for an international oil and gas company in a $1 billion lawsuit filed by a municipality as well as lawsuits by 35,000 area residents alleging personal injury, property damage, and lost wages following an incident and large fire at one of the company’s refineries in California. Led the team that ultimately defeated the municipality’s first-of-its-kind claim for lost tax revenue, which led to a favorable settlement of the city’s remaining claims.* 
  • Co-lead counsel for an international oil and gas company in connection with lawsuits claiming that various consumer and related products and their active ingredients caused non-Hodgkin’s lymphoma and Parkinson’s disease.*
  • Lead trial and appellate counsel to an international oil-and-gas company in DC Superior and US District Court cases, as well as three appeals to the United States Court of Appeals for the DC Circuit, alleging environmental-racism, property-damage, and other claims in connection with a underground gasoline leak over 30 years ago in a neighborhood on the DC/Maryland border. The matters involved organized media coverage, YouTube and Twitter campaigns, and public protests at various locations including outside the White House and law-firm offices.  Both the DC Superior and federal district courts dismissed all claims and in July 2020, the DC Circuit granted summary affirmance in connection with the appeals.*
  • Lead counsel for an international oil and gas company in a lawsuit in the U.S. District Court, District of Maryland, alleging breach of contract, indemnification and other claims concerning remediation of leaks from an underground pipeline near Baltimore’s harbor that the client sold in 1994. Successfully resolved through mediation led by the federal Magistrate Judge.*
  • Represented of one of the world’s largest global oil and gas producers in a qui tam suit in the Eastern District of Texas alleging violations of Department of the Interior’s royalty calculation regulations.*
  • Represented an international oil and gas company before the United States Supreme Court.*
  • Represented an applicant in the DOJ Antitrust Division’s Corporate Leniency Program and led the nearly two-year internal investigation and government proffers in connection with the leniency application. The matter was resolved when the Justice Department closed the investigation.*
  • Represented one of the nation’s largest financial institutions in the In re Municipal Derivatives Antitrust Litigation in the Southern District of New York in connection with allegations of price-fixing, bid rigging and customer allocation in the numerous putative class and individual actions and various federal and state investigations. Directed the client, a leniency applicant, with respect to the cooperation and damage-limitation provisions of the Antitrust Criminal Penalties Enhancement and Reform Act of 2004 (ACPERA).*
  • Represented an international oil and gas company in connection with challenges to the California Air Resources Board’s proposed Clean Fuel Outlets regulation, which would have required producers and importers of gasoline in California to offer hydrogen fuel at certain gasoline stations.*
  • Represented: i) a Department of Defense contractor in connection with civil and criminal investigations involving allegations of procurement fraud, alleged violations of the Foreign Corrupt Practices Act and unauthorized leaks of top-secret information; ii) an international construction and engineering company in connection with an SEC investigation involving allegedly false and misleading statements and studies offered in support of the issuance of municipal bonds; and iii) an international company in connection with a DOJ Antitrust Division civil and criminal investigation involving alleged collusion in the beef-packing industry.*
  • Pro bono representation of an Air Force National Guard Technical Sergeant and an Army Specialist before the Physical Disability Board of Review. The Technical Sergeant had been medically separated for congestive heart failure with a 10% disability rating, while the Specialist had been separated with a 20% rating following a career-ending training accident in Airborne School. Following written submissions, the PDBR increased the Technical Sergeant’s rating to 60% and the Specialist’s rating to 50%. The PDBR reclassified both as medically retired with retroactive benefits to their severance dates in the early 2000s, including TRICARE medical coverage and other lifetime benefits.*
  • *Denotes work done prior to joining McGuireWoods.