IUCLID, the International Uniform ChemicaL Information Database, is a software application system for managing data on intrinsic and hazard properties of chemical substances and reporting to the regulatory authorities. The first version was originally developed by the European Chemicals Bureau (ECB) of the European Commission in 1993 to meet the requirements of the Council Regulation (EEC) 793/93 on the "Evaluation and Control of the Risks of Existing Substances" (short "Existing Substances Regulation"). "Existing substances" are those substances which were deemed to be on the European Market before September 18, 1981 and are listed in the EINECS inventory (European Inventory of Existing Commercial chemical Substances). The Existing Substances Regulation obliges industry to submit all readily available data on "High Production Volume Chemicals" (HPVCs). IUCLID was also used as the basic tool for data collection and evaluation within the EU Risk Assessment Programme.

IUCLID is operational in all EU Member States Competent Authorities involved in the EU Existing Chemicals Risk Assessment Programme, at the OECD headquarters in Paris, at UNEP-IRPTC (Geneva), government institutions in Japan and in the US EPA. A number of companies use IUCLID as their in-house database system and for reporting EU Chemicals Legislations.

Between 1993 and 2001, IUCLID was further modified and expanded to address other data requirements. In 1998 and 2000, versions 3.05 and 3.1.1 were released to fulfil the requirements of the OECD SIDS and HPVC activities of ICCA and US EPA, respectively. Shortly thereafter, version 3.2 was released for use in the notification procedure of the EU Biocidal Products Directive 98/8/EC (BPD). Finally, IUCLID version 4.0 was released in 2001 to cover both existing chemicals and biocides.

Despite of the consistent improvement of IUCLID during these years, it turned out that the structure of IUCLID data entry forms was rather limited, particularly to meet the concept of robust study summaries, which is based on a detailed and structured description of methodology and results. As a workaround structured Freetext templates were used to supplement the limited number of defined data entry fields. In order to provide a tool for the chemicals industry to fulfil its obligations under the REACH Regulation (EC) No. 1907/2006 (short "REACH"), IUCLID 4 was completely redesigned. The new system, IUCLID 5, for which this manual was developed, was released in 2007.

Apart from a completely new software technology and a modern user interface, the data entry forms of the various IUCLID 5 sections are much more structured than those in IUCLID 4. This is particularly true for the endpoint data sections, in which the (robust) study summaries and any other relevant substance-related information need to be recorded. These data entry forms were modelled on the OECD Harmonised Templates which were developed towards the reporting of study summaries on any type of chemical (e.g. pesticides, biocides, industrial chemicals). These templates include a number of additional distinct data entry fields compared to the previous IUCLID versions, but also adopted the concept of Freetext templates in an attempt to still limit the number of fields in general. Apart from additional scientific fields, IUCLID 5 also contains more fields for administrative data. Irrespective of the number of fields provided, IUCLID per se does not prescribe how detailed the study summaries should be recorded. The relevant guidance for the respective chemical programme should be referred to on this in addition to the guidance given in this manual. This holds particularly true for IUCLID 4 datasets migrated to IUCLID 5 based on the migration tool, where a pragmatic approach may be used governed by the question whether the relevant information is provided and not how it is provided. But in the end, it depends on the requirements of the regulatory programme as to how close the structure of the new IUCLID has to be followed. In any case, data entry fields that are included in completeness checks by regulatory authorities should be taken into consideration.