Examples of such identifiers for chemicals include the Chemical Abstracts Service (CAS) registry number and the International Union of Pure and Applied Chemistry (IUPAC) International Chemical Identifier or InChI . The first is assigned to all chemical substances after publication and indexing, while the second can be computed according to an agreed set of rules and abstractions to represent chemical structures. However, these two identifiers are still not sufficient for the wide range of nanosafety research projects being undertaken. The InChI is based on chemical graphs and cannot fully describe the chemistry of engineered nanomaterials (ENMs), although a draft extension of InChI for nanomaterials (NInChI) has been defined recently . The goal of the NInChI is to describe core features of nanomaterials (from their centre towards their surface, the aspect most closely linked to their interactions and potential toxicity). Its purpose is to support integration of datasets of similar materials, and as such is considered a group identifier. CAS registry numbers cannot be created by researchers themselves. This is an issue for internal communication and reporting in (European) research projects where the full physicochemical properties are often measured, but not always reported outside the project, with scientific publications often coming well after the project has ended. Thus, to meet the FAIR requirements, we need a complementary global, unique identifier for unpublished or internally published communication and reporting that can be used without disclosing sensitive or embargoed information but which allows linking of knowledge in a clearly defined way, supporting our nanosafety research and development .