What are the OECD Harmonised Templates?

The OECD Harmonised Templates (OHTs) are standard data formats for reporting information on chemicals to determine their properties or effects on human health and the environment (e.g. toxicokinetics, skin irritation, repeated dose toxicity, biodegradation in soil, metabolism of residues in crops, etc.) and also to describe their use and related exposure to workers, consumers and the environment. They can be used as specifications for data entry screens in data management systems (e.g. IUCLID). Data elements, which could be relevant for the risk assessment of chemicals, are listed as well as the format in which the information should be entered and stored electronically, together with field-specific help texts intended to guide end users.

The OHTs constitute harmonised tools that are useful to developers and maintainers of databases on chemicals. Harmonisation in this context means that these templates can be used as models for reporting studies and other information on any type of chemicals (e.g. pesticides, biocides, industrial chemicals, food/feed additives).


What do they contain?

As the templates are intended to serve as standard formats for summarising data contained in any study report or publication related to particular endpoints, including studies that were not conducted according to current guidelines, they are designed in a very flexible way. This includes:

  • structured elements (i.e. fields, picklist items, freetext prompts, predefined tables and executive summaries) 
  • picklists for specific test guidelines which contain the most often cited guidelines
  • help texts and guidance notes which explain what kind of data entry is expected in a given field, but do not necessarily indicate whether the corresponding data are requested by any test guideline. However, most templates are nevertheless built around the OECD Test Guidelines, as these are internationally agreed standards.

The OECD Harmonised Templates allow for providing administrative data, stating the endpoint addressed by the study summary, describing the materials and methods used during the test, reporting the results and their possible discussion, delivering the applicant’s summary and conclusion. It is also possible to make overall remarks and to attach background materials that can be useful to the end users.


Are all elements contained in the OHTs useful in all cases? 

Not always. The degree of complexity used in these templates follows the needs of the key study / robust study summary approach. The fields provided should be considered as a maximum degree of detail. It is generally accepted that much less details are needed in case of study summaries (compared to robust study summaries).

In addition, some templates being designed to cover several test methods dealing with the same endpoint, only a part of the template might be useful for reporting summaries of studies performed according to a single method.


What are the different types of OHTs?

The endpoint-oriented templates constitute the core of the set of the available OHTs, targeted to specific hazards assessment and/or given test methods.

Beside them, other types of templates are complementary: the OHTs on physico-chemical properties are designed to characterise the chemical being studied, including nanomaterial properties where applicable.

The template No.201 on ‘Intermediate effects’, allows to report non-apical observations, i.e. intermediate effects at molecular, subcellular, cell, tissue or organ level which can be relevant when studying the hazard posed by a compound.

The series of OHTs on Use and exposure information (OHTs 301 to 306) enables to report on another range of information such as the life cycle of the substance, its uses and service life, as well as the conditions of use, releases and exposures to the substance.

Other templates are being developed to fit with new testing methods and cover emerging needs, and the series of OHTs is regularly enriched with new templates.


Do OHTs provide specific language for databases?

Yes, specific language for databases is made available. By using the OECD Harmonised Templates, governments and industry are able to electronically exchange test study summary information. In order for information technology developers to build data entry screens and/or database systems based on the OHTs, each template has to have a corresponding XML structure. An XML (Extensible Mark-up Language) schema, or export format, is a common computer language which facilitates the electronic exchange of data across different computer systems for data entry, storage and management. 


Is IUCLID using the OHTs? 

Yes, it is. IUCLID, the International Uniform ChemicaL Information Database developed by the European Chemicals Agency (ECHA), is the first system that implemented completely the OECD Harmonised Templates. Information compiled in IUCLID can be exchanged with other databases that use the same OHTs XML schemas, even if the underlying computer systems are different. By using IUCLID functionalities and reporting a large range of chemical test summaries in the system, IUCLID users are regularly identifying gaps or elements that could be improved in the OHTs.

IUCLID is a computer software that is available for free download from the ECHA website. The latest version includes the most recent templates.

For an overview of IUCLID features and how IUCLID can be configured and customised to manage chemical data in different contexts, see Customisation Opportunities of IUCLID for the Management of Chemical Data in the OECD Series on Testing and Assessment.



These OECD Harmonised Templates should not be seen as constituting OECD data requirements. Only those fields that are deemed relevant by a regulatory authority would be completed in that jurisdiction (i.e., all of the fields may not be completed in all countries). As to the level of detail required the relevant guidance documents for the respective chemical programme should be consulted.

The OECD Templates are also not prescriptive as to the order of appearance of any data entry fields or how the fields are technically implemented, as long as this does not affect the harmonised and agreed upon data exchange format.


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