IUCLID (; International Uniform Chemical Information Database) is a software application to capture, store, maintain and exchange data on intrinsic and hazard properties of chemical substances. Distributed free of charge, the software is especially useful to chemical industry companies and to government authorities. It is the key tool for chemical industry to fulfill data submission obligations under REACH, the most important European Union legal document covering the production and use of chemical substances. The software is maintained by the European Chemicals Agency, ECHA. The latest version, version 6, was made available on 29 April 2016. History IUCLID versions 1 to 4 1993: First version of IUCLID for the European Existing Substances Regulation 793/93/EEC. 1999: IUCLID becomes the recommended tool for the OECD HPV Programme. 2000: IUCLID is the software prescribed in the EU Biocides legislation to notify existing active substances (Art. 4 of Commission Regulation (EC) No 1896/2000). IUCLID 4 was used worldwide by about 500 organizations. These included chemical industry companies, EU Member State Competent Authorities, the OECD Secretariat, the US EPA, the Japan METI, and third party service providers. IUCLID 5 In 2003, when it became clear that the REACH proposal would be adopted by the European Union, the European Commission decided to completely overhaul IUCLID 4 and to create a new version, IUCLID 5, which would be used by chemical industry companies to fulfill their data submission obligations under REACH. Migration of data in the IUCLID 4 format was supported by IUCLID 5.1. IUCLID 5.1 became available on 13 June 2007. IUCLID is also mentioned in article 111 of the REACH of the REACH legislation as the format to be used for data collection and submission dossier preparation. The following IUCLID 5 major versions have been released: IUCLID 5.0: 12 June 2007 IUCLID 5.1: 16 January 2009 IUCLID 5.2: 15 February 2010 IUCLID 5.3: 24 February 2011 IUCLID 5.4: 5 June 2012 IUCLID 5.5: 2 April 2013 IUCLID 5.6: 16 April 2014 IUCLID 5 Data Format and Exchange Data that can be stored and maintained with IUCLID encompass information about: The party running IUCLID (production sites, contact persons etc.) The chemical substances managed by the company, namely their identity, composition, and supporting analytical data reference information like CAS number and other identifiers, classification and labelling physical/chemical properties, toxicological properties, eco-toxicological properties. OECD and the European Commission have agreed on a standard XML format (OECD Harmonized Templates) in