Before a probit function is included in the calculation method, a step-by-step process of derivation, evaluation and formalisation is followed.

Step-by-step process of derivation, evaluation and formalisation

The probit function has a certain status in the various stages of this process:

  • The ‘voorgesteld’ status (proposed):
    The probit function has been derived by the author of the substance document and the independent expert panel on probit functies has approved the probit function on scientific grounds. The substance document is published online for external comment. 
  • ‘inhoudelijk vastgesteld’ status (approved content):
    The derived probit function is the result of a review of the proposed probit function and the received comments. This probit function contains the most current scientific insights.

For a current overview of the status of probit functions, see the Probit Functions Status Overview (NL).


The derivation of a probit function takes place using an established methodology based on information from scientific literature. The methodology is described in the RIVM report Method for derivation of probit functions for acute inhalation toxicity (2015).

The derivation method has been developed by the expert panel under the responsibility of the RIVM. The methodology has been reviewed by an international panel of experts. They approved the methodology with some recommendations for adaptation. A report of this international review can be found on this page.

The most recently updated version of the template can be found at the Omgevingsveiligheid (NL).

The chemical industry is an important source of toxicological information. The activity plan of the expert panel is made public in an early stage to give the industry the opportunity to provide relevant information about the substances. Furthermore the industry is given the opportunity to indicate for which substance a probit function is relevant.


The proposed probit functions and any comments received are scientifically evaluated by an independent scientific expert panel. The expert panel consist of 6 members:

  • A. (Anneke) Wijbenga (chair)
  • Dr Doctor (Doctor). J.H.E. (Josje) Arts MSc, AkzoNobel
  • Dr. P.J. (Peter) Boogaard, WUR
  • P.M.J. (Peter) Bos MSc, RIVM
  • Dr. H. (Hans) Muijser
  • Dr. M. (Marc) Ruijten MSc, CrisisTox Consult

External public comment

After evaluation by the expert panel the substance documents are assigned the status ‘voorgesteld’ (proposed). The documents are published on this website in order to provide interested parties with the opportunity to comment or provide additional information. A minimum term of 6 weeks applies. Interested parties are informed of the publication of new substance documents via e-mail. 


Any comments on the substance documents will be reviewed by the expert panel and where needed the documents will be adapted. Subsequently the substance documents are assigned the status ‘inhoudelijk vastgesteld’ (approved content). The RIVM advices to use this probit function for the QRA, as it contains the most recent scientific insights.


The ministery of Infrastructure and Water management decides whether to formally implement a probit function.


For certain substances, the derivation of a probit function is considered to be of general interest, for instance because the substances are often found in quantitative risk assessments (QRAs). For these substances, the compilation of the substance dossier and the derivation of the probit function are dealt with by the RIVM. An updated version of the plan can be found at Werkplan toetsgroep (NL).

If a certain party requires a probit function which is not derived by the expert panel, the compilation of the substance dossier and the derivation of the probit function are the responsibility of this party. Furthermore, an applicant may submit a (well-founded) request for the inclusion of a certain substance in the planning. Correspondence concerning the derivation and formalisation of probit functions runs via the helpdesk Omgevingsveiligheid (NL).

Additional information

Further information about the derivation of proposed probit functions can be obtained at our helpdesk (NL) as required.