Patrick W. Dennis is a partner in the Los Angeles office of Gibson, Dunn & Crutcher.  He is a member of the Environmental Litigation and Mass Tort Practice Group.  Mr. Dennis has extensive experience representing clients in general manufacturing, energy, banking, aerospace, real estate, construction, electronics, oil and gas, cement making, and lead recycling in a wide range of environmental matters.  He has substantial experience in the following areas:

• Toxic Tort Litigation
• CERCLA Cost Recovery Litigation
• Defense of Environmental Enforcement Actions by Public & Private Parties
• Complex or Large Transactions with Environmental Issues
• Environmental Laws and Regulations Counseling

Mr. Dennis is consistently named among the nation’s leading environmental law attorneys.  He was selected to the 2023 Lawdragon Green 500: Leaders in Environmental Law  guide for the past two editions, including the inaugural edition in 2021, which recognizes environmental justice leaders.  Who’s Who Legal recognized Mr. Dennis in its 2023 Who’s Who Legal Thought Leaders: USA  guide, which features lawyers with “vast expertise and experience advising on some of the world’s most significant and cutting-edge legal matters,” and the “ability to innovate, inspire, and go above and beyond to deliver for their clients.”  He was also listed, for outstanding work in environmental law, in Who’s Who Legal’s Environment  2022.  In 2019, Mr. Dennis was nationally ranked as one of just ten “Leading Lawyers” in Environmental Litigation in The Legal 500 United States, and in all prior years going back to 2009, he was ranked as one of just 10 or 11 such Leading Lawyers.  In 2017, Mr. Dennis was awarded the Legal 500 Hall of Fame award for being a “leading lawyer” for the past six consecutive years.  In 2021 and again in 2022 Mr. Dennis was ranked as a California Environmental Law “Senior Statesman” and from 2010 through 2020, he is in the top tier, Band 1, ranking for California environmental law in Chambers USA: America’s Leading Lawyers for Business.  He has also been selected by his peers for inclusion in The Best Lawyers in America© for the field of Environmental Law and Litigation-Environmental.  In 2017, he was listed in Expert Guide’s Energy and Environment Guide as a leading practitioner in the area of Environmental law.  From 2012-2014, Best Lawyers named him Los Angeles Litigation – Environmental “Lawyer of the Year.”  Mr. Dennis received the 2016 CLAY (California Lawyer Attorney of the Year) award in the Real Estate and Development category for his role in the redevelopment of the Hollywood Park racetrack into a world class football stadium to house the Los Angeles Rams for their return to Los Angeles.

In 2009, Mr. Dennis was elected to the exclusive American College of Environmental Lawyers by his peers.  He was also a Chair and a founding member of the Los Angeles County Bar Association Environmental Law Section.  Between 2017-2019, Mr. Dennis was the Chair of the Board of Trustees for the California Science Center Foundation.

Among other successful appellate arguments, Mr. Dennis represented (1) the Atlantic Richfield Company in the Ninth Circuit Court of Appeal decision reported at Wilshire Westwood Associates v. Atlantic Richfield Corporation, 881 F.2d 801 (1988) (excluding refined petroleum products from CERCLA coverage under the so-called “petroleum exclusion”); (2) the Climate Action Reserve in the California Second Appellate District decision reported at Our Children’s Earth Foundation v. California Air Resources Board, 234 Cal. App. 4^th 870 (2015) (upholding the validity of the offset protocols for voluntary carbon emission reductions as part of California’s landmark Greenhouse Gas cap and trade regulations); Philip Morris USA in the trial court and appeal in Aranda v. Philip Morris USA Inc., 183 A.3d 1245 (Del. 2018) (establishing a new and more rigorous test for fórum non conveniens  in Delaware by Delaware’s Supreme Court).

He received a B.S. (Civil Engineering – 1976); M.S. (Mechanical Engineering – 1978); and a J.D./MBA (1982), all from the University of California, Los Angeles. Mr. Dennis has practiced exclusively in the environmental law area since graduating from law school.