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Daria Diaz has practiced environmental law for more than 30 years. She represents local, national, and international energy and industrial clients in a variety of substantive areas including environmental, natural resources, energy, oil and gas, and toxic torts. 

Throughout her career, Daria has litigated a variety of environmental and energy law cases, including legacy oil field cases, and cases involving solid waste disposal and recycling, underground storage tanks, underground injection wells, coastal and wetlands issues, natural resource damages, and hazardous waste treatment, storage and disposal. 

Additionally, she handles environmental regulatory law, including permitting, compliance, and enforcement.   Daria assists and counsels clients in permitting and enforcement actions before federal and state agencies, on release notification issues and environmental audits, and has participated in rulemaking efforts at both the federal and state level. She also represents clients in insurance, real estate, and transactional matters involving environmental issues.

Representative Matters

  • Defense of numerous legacy oilfield site lawsuits for major and independent oil and gas companies.
  • Defense of major oil and gas producer in royalty underpayment litigation.
  • Defense of major oil company in connection with an Oil Pollution Act cost recovery action and associated tort claims.
  • Representation of a refinery in connection with administrative enforcement actions brought by the Louisiana Department of Environmental Quality.
  • Counsel to several business and industrial clients–representation includes various environmental regulatory, adjudicatory, compliance, and permitting issues.
  • Defense of a large real estate developer in criminal and civil enforcement actions for alleged Clean Water Act violations.
  • Representation of a large landowner in a NEPA challenge to a federal siting proposal.
  • Advised a marine terminal facility on Clean Air Act and Clean Water Act permitting issues.
  • Advised a solid waste company on permitting and associated regulatory issues in connection with the operation of a landfill.
  • Provided advice on the applicability of the Clean Air Act, Clean Water Act, and Oil Pollution Act, including permit and permit transfer issues in connection with an asset purchase.
  • Defense of a large municipality in an action filed by the United States under CERCLA seeking access to property for purposes of response action.
  • Counsel to numerous clients on environmental issues associated with real estate transactions, asset transfers, and business acquisitions.

Professional & Civic Activities

Professional and Civic Activities

  • Louisiana State Bar Association member and Past Chair of the Environmental Law Section.
  • Baton Rouge Bar Association member.

Teaching Positions

  • Daria served as adjunct faculty at Tulane Law School where she taught a class on Environmental Enforcement.

Honors & Awards

Honors & Awards

  • Best Lawyers in America 2023 and 2024.
  • Chambers and Partners 2010 – 2024.
  • New Orleans Magazine "Top Lawyer" 2012 – 2023.

News & Events


"Environmental Enforcement," Tulane Law School Spring Semester 2007.

"Land Use and Environmental Group: The Role of the Private Sector in Redeveloping Major Areas Impacted by Catastrophic Events," American Bar Association Real Property and Probate Section, 17th Annual Real Property Symposium, San Diego, CA 2006.

"Solid Waste Issues and Current Developments," March 2002, sponsored by the Tulane Law School Environmental Institute.

"Negotiating EPA Compliance Agreements," March 2000, sponsored by the Tulane Law School Environmental Institute.

"Safe Drinking Water Act, Amendments of 1986 - Source Water Protection," February 1999, sponsored by the Tulane Law School Environmental Institute.

"Environmental Enforcement," February 1998, sponsored by the Tulane Law School Environmental Institute.

"Environmental Justice," December 1997, sponsored by the Louisiana Trial Lawyers Association.

"Environmental Advocacy and Litigation Seminar," Tulane Law School 1994-1996.

"Administrative Process and Procedure - Permitting and Enforcement," February 1997, sponsored by the Tulane Law School Environmental Institute.

"Citizen Participation in DEQ Permitting and Enforcement Proceedings," March 1995, sponsored by the Louisiana State Bar Association.

"Pollution Control and Environmental Regulation for Geologists," November 1992, University of New Orleans.


  • Recent Developments Environmental Law, Louisiana Bar Journal, Vol. 52, No. 1, June 2004.
  • Panelist LSU Environmental Round Table:  Louisiana Department of Environmental Quality Update, April 29, 2004.
  • Recent Developments Environmental Law, Louisiana Bar Journal, Vol. 51, No. 1, June 2003.
  • Environmental Justice, Chapter 30, Louisiana Environmental Law Handbook, Lawyers Cooperative Publishing (2000).
  • Trashing the Final Frontier:  An Examination of Space Debris From a Legal Perspective, 6 Tulane Environmental Law Journal  369 (1993).
  • Pro Se Litigants in the Federal Courts, The Specter of Rule 11 of the Federal Rules of Civil Procedure, (co-author) The Justice Professional, Vol. 6, Number 1 (Winter 1992).

Practice Areas

Bar Admissions

  • Louisiana Federal and State Courts


Tulane University Law School, LL.M. in Energy and Environment, 1993

Florida State University College of Law, J.D., 1986

  • Order of the Coif
  • Articles and Notes Editor, Journal of Land Use and Environmental Law

University of Texas at Arlington, with high honors, 1983

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