LEGAL BRIEFING ON THE ARBITRAL TRIBUNAL'S DECISION TO DENY THIRD PARTY SUBMISSION IN ODYSSEY MARINE EXPLORATION, INC. V. THE UNITED MEXICAN STATES

This legal briefing by the Center for International Environmental Law (CIEL) analyzes the decision of an arbitral tribunal to deny an amicus curiae submission by CIEL and the Sociedad Cooperativa de Producción Pesquera Puerto Chale in the case of Odyssey Marine Exploration, Inc. v. United Mexican States. The briefing argues that the denial undermines the legitimacy of the investor-state dispute settlement (ISDS) system and ignores the significant environmental and human rights risks associated with the Don Diego seabed mining project.

• On December 20, 2021, the arbitral tribunal in the case Odyssey Marine Exploration, Inc. v. United Mexican States (ICSID No. UNCT/20/1) denied an application for leave to file an amicus curiae brief by the Center for International Environmental Law (CIEL) and the Sociedad Cooperativa de Producción Pesquera Puerto Chale.
• The tribunal's majority denied the submission on the grounds that neither CIEL nor the Cooperativa possessed a significant interest in the arbitration or could provide knowledge or insight that differed from the disputing parties.
• The Don Diego Project, a seabed mining project off the coast of Mexico’s Baja California Peninsula, is identified as posing risks to the marine environment of the Gulf of Ulloa and the local population, specifically fisherfolk.
• The briefing asserts that the Don Diego Project is a matter of public interest because it is incompatible with a fishing refuge zone and a fishing concession zone, threatens regional biodiversity, and infringes on human rights including the rights to health, work, a healthy environment, and cultural life.
• Arbitrator Professor Philippe Sands dissented from the majority decision, arguing that the Cooperativa's unique perspective as a directly affected community was valuable and that the decision to exclude them undermines the legitimacy of the proceedings.
• The briefing highlights a systemic issue in ISDS where the power to admit amicus submissions is treated as a discretionary power of the tribunal rather than a duty to recognize public interest representation when specific criteria are met.

APA

Center for International Environmental Law (2022). LEGAL BRIEFING ON THE ARBITRAL TRIBUNAL'S DECISION TO DENY THIRD PARTY SUBMISSION IN ODYSSEY MARINE EXPLORATION, INC. V. THE UNITED MEXICAN STATES. https://www.ciel.org/wp-content/uploads/2022/02/Legal-Briefing-on-the-Arbitral-Tribunals-Decision-to-Deny-Third-Party-Submission-in-Odyssey-Marine-Exploration-Inc-v-The-United-Mexican-States_English.pdf

Chicago

Center for International Environmental Law. LEGAL BRIEFING ON THE ARBITRAL TRIBUNAL'S DECISION TO DENY THIRD PARTY SUBMISSION IN ODYSSEY MARINE EXPLORATION, INC. V. THE UNITED MEXICAN STATES. 2022. https://www.ciel.org/wp-content/uploads/2022/02/Legal-Briefing-on-the-Arbitral-Tribunals-Decision-to-Deny-Third-Party-Submission-in-Odyssey-Marine-Exploration-Inc-v-The-United-Mexican-States_English.pdf.

Wikipedia

{{cite report |author=Center for International Environmental Law |title=LEGAL BRIEFING ON THE ARBITRAL TRIBUNAL'S DECISION TO DENY THIRD PARTY SUBMISSION IN ODYSSEY MARINE EXPLORATION, INC. V. THE UNITED MEXICAN STATES |date=February 2022 |url=https://www.ciel.org/wp-content/uploads/2022/02/Legal-Briefing-on-the-Arbitral-Tribunals-Decision-to-Deny-Third-Party-Submission-in-Odyssey-Marine-Exploration-Inc-v-The-United-Mexican-States_English.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{centerforinternationalenvironmentallaw2022legal, author = {{Center for International Environmental Law}}, title = {{LEGAL BRIEFING ON THE ARBITRAL TRIBUNAL'S DECISION TO DENY THIRD PARTY SUBMISSION IN ODYSSEY MARINE EXPLORATION, INC. V. THE UNITED MEXICAN STATES}}, institution = {Center for International Environmental Law}, year = {2022}, month = feb, url = {https://www.ciel.org/wp-content/uploads/2022/02/Legal-Briefing-on-the-Arbitral-Tribunals-Decision-to-Deny-Third-Party-Submission-in-Odyssey-Marine-Exploration-Inc-v-The-United-Mexican-States_English.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }