There are various types of occupational accidents that can occur during work. For example, people can fall from a ladder or become involved in an accident with a machine. In 2003, RIVM started a project aimed at calculating the risk of an occupational accident. For that purpose, databases were created, various projects were carried out, and a calculation model was developed. The calculation model and associated tools are no longer actively managed. However, the methodology remains available. This page provides a brief historical overview of the available information.

In order to be able to calculate the risk of an occupational accident, information is needed on the frequency and causes of occupational accidents. RIVM developed a unique database - Storybuilder - for that purpose, which is still used and managed. This database contains data on serious accidents that are reported to and investigated by the Netherlands Labour Authority and the causes of these accidents.

However, more information is needed to calculate risks. For example, insight is needed into the activities and working conditions of the (average) worker. In addition, a systematic method is needed for collecting the necessary data and using them for calculations. In order to achieve this, the ‘Occupational Risk Model’ (ORM) and the ‘Occupational Risk Calculator’ (ORCA) were developed. The activities that led to these developments were started around 2003 at the request of the Ministry of Social Affairs and Employment (SZW). These developments took place in close collaboration with the Netherlands Labour Authority and various scientific partners.

Data from Storybuilder as well as data on the exposure of workers to hazards served as important input for the development of the ‘Occupational Risk Model’. By combining various data, the risk of accidents resulting in serious injury or death can be calculated per activity, job, company, or industrial sector. The WebORCA tool has made this information available for application by individual companies.

The ‘Occupational Risk Model’ and the ‘Occupational Risk Calculator’ are no longer actively managed. Also WebORCA has not been offered since 2021 and is no longer available online. One of the main  reasons is that the underlying data on the exposure to hazards is no longer up-to-date. This is also the case for the software.

The methodology remains available and has been described in detail in publicly available reports and in various articles in the scientific literature. References to reports and publications are listed below. Additional details about the methodology, its application, and the calculations can be requested, if desired, from RIVM via

Other articles

Various articles were also published in the scientific literature in addition to the above. These articles focused on aspects such as specific target groups, working methods, or sectors. A few examples are presented below.

  • Aneziris O.N., Papazoglou I.A., Konstandinidou M., Damen M., Kuiper J., Bellamy L.J., Mud M.L., Baksteen H., Oh J.I.H., Occupational Risk Management for Electrical Hazard, European Safety and Reliability Conference (ESREL), Sept 7-10, 2009, Prague, Czech Republic.
  • Aneziris O.N., Papazoglou I.A, Doudakmani O., Assessment of occupational risks in an aluminium processing industry, International Journal of Industrial Ergonomics, 2010, 40, 321-329.
  • Aneziris O.N., Papazoglou I.A, Kallianiotis D., Occupational Risk of tunnelling construction, Safety Science, 2010, 48, 964-972.
  • Aneziris O.N., Topali E., Papazoglou I.A, Occupational risk of building construction, Reliability Engineering and System Safety, 2012, 105, 36-46.
  • Damen M., Wouters R., Berkhout P.H.G., Bellamy L.J., Mud M.L., Manuel H.J., Oh J.I.H., Risks to young people at work. More experience or less exposure?, International Congress Working on Safety (WOS), Sept 11-14, 2012, Sopot, Poland.
  • Sol V., Manuel H.J., Bellamy L.J., Damen M., Mud M.L., Oh J.I.H., Afwegen van kosten en baten voor reductie van arbeidsongevallen in de kartonfabricage, Tijdschrift voor toegepaste Arbowetenschap, 2012, 25 (01), 16-21.
  • Bellamy L.J., Mud M.L., Manuel H.J., Oh J.I.H., Analysis of Underlying Causes of Investigated Loss of Containment Incidents in Dutch Seveso Plants Using the Storybuilder Method, Journal of Loss Prevention in the Process Industries, 2013, 26 (iss 6), 1039-1059.
  • Bellamy L.J., Aneziris O.A., Comparison of occupational accident risks and underlying causes between temporary and non-temporary workers, Safety Science Monitor, 2015, 19, Issue 2, Article 3.