Introduction The Network on the Coordination and Harmonisation of European Occupational Cohorts (OMEGA-NET) was set up to enable optimization of using industrial and general population cohorts across Europe to advance aetiological research. High quality harmonised exposure assessment is crucial for such international occupational health research.

Objective To facilitate an integrated research strategy, a concerted effort is needed to catalogue occupational exposure information. This study aims to provide a comprehensive overview of exposure assessment tools that could be used for occupational epidemiological studies.

Methods An online inventory was set-up to collect meta data on exposure assessment tools (https://occupationalexposuretools.net/). Occupational health researchers were invited via newsletters, editorials and individual mails to provide details on job-exposure matrices (JEMs), exposure databases, and occupational coding systems and crosswalks, with a focus on Europe.

Results Meta data on 38 JEMs and 9 national exposure databases had been collected up to May 2021. Most JEMs on which these data were entered were developed in the Netherlands and the Nordic countries. A wide variety of exposures was covered, with dusts and fibres (in 15 JEMs) being the most common types. Just a few JEMs covered biological factors (5) and employment conditions (1). Dusts and fibres were also the most common exposures in the databases (6 out of 9), followed by solvents and pesticides (both in 4 databases). Furthermore, information was collected on 24 occupational coding systems from more than 10 countries, indicating related systems as well as the availability of crosswalks or automated coding from free-text.

Conclusion This inventory forms the basis for a searchable web-based database of meta-data on existing occupational exposure information, so that researchers can find the available tools for assessing occupational exposures in their cohorts. This inventory remains open for further additions, to enlarge its coverage and include newly developed tools