On June 30, 2025, the Organisation for Economic Co-operation and Development (OECD) published a report entitled 2D Titanium Carbide MXenes: Case Study Report on Advanced Materials. Within OECD's Working Party on Manufactured Nanomaterials (WPMN), the Steering Group on Advanced Materials conducted a case study on the potential issues of 2D titanium carbide MXenes. The report describes MXenes as "a group of [two-dimensional (2D)] advanced materials composed of transition metal carbides or nitrides that has received increased attention in research and innovation." The results of the case study were presented during an online international OECD WPMN workshop in 2024, where additional inputs and perspectives on the findings were also gathered. The report provides a summary of the main findings of the case study and the workshop. The case study identified various potential issues for titanium carbide MXenes on the topics of safety for human health and the environment, sustainability, and regulation, including:
- There is currently no clear evidence that MXenes are highly acutely toxic, and information gaps preclude making definitive conclusions on their safety. Information for a comprehensive risk assessment is lacking in several areas, including pulmonary hazards, genotoxicity potential, long-term effects on humans (both oral and via inhalation) and the environment, kinetics in the human body, and environmental fate.
- The quality of experimental MXenes studies and reporting is currently not sufficient and requires improvement to inform risk assessment, regulatory actions, and policy. Issues are noted among others on sample preparation, material characterization, and use of benchmark materials.
- Information gaps on the sustainability of titanium carbide MXenes have been identified, including life cycle and environmental impacts at production volumes larger than lab scale, recyclability, and reusability.
- Concerns have been raised that some existing legislation and risk assessment instruments may not be fit-for-purpose for MXenes.
The report identifies potential issues and suggested follow-up actions.
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