DOHSBase Compare

With DOHSBase Compare® you get:

  • The most appropriate occupational exposure limit values (OELV’s) and measurement methods. Both data are presented according to a hierarchy (see “Search” mode);
  • The physico-chemical properties of a substance;
  • Harmonized CLP information and labelling of a substance. In addition, DOHSBase has developed a substantiated classification (self-classification) for an increasing number of substances with a non-harmonized classification.
  • It is possible to make a comparison between different substances in terms of the risk potential at the workplace. Hereby, a so-called ‘Risk Assessment Score’ (RAS) is calculated in the Compare Mode.


Search and Find Mode

In the search mode of DOHSBase Compare, you can quickly check if there are existing OELV’s and measurement methods for the substances you are looking for. The search possibilities are: (a part of) the name or the synonym, the CAS-number and the EC-number. Search and filter can also be based on physico-chemical properties or hazard classification as well as information about the OELV or measurement method (value, source [e.g. Health Council, NIOSH], medium of the limit [workplace atmosphere, urine, blood]).



Occupational Exposure Limits

The OELV’s are presented in the “Limit Values” tab according to a fixed hierarchy (see below). For each substance, the carrier medium of the OELV (air, blood, urine) and reference period, maximum 4 limits are presented. If there are legal limit values, these are always shown first in the National versions. In the EU-version, the “Indicative Occupational Exposure Limit Values” (IOELVs) and “Binding Limit Values” (BLVs) are shown as “legal limit values.”


Hierarchy OELV’s

The origin for the hierarchy for limit OELV’s is the Dutch Guideline for Limit Values developed by the SER (; in Dutch only) in 2007. We have adapted the hierarchy to the latest international insights and developments around REACH and the DNEL’s[1]. DOHSBase Compare currently uses a hierarchy as presented in 2014 at a meeting section Occupational Toxicology of the Dutch Society of Toxicology (NVT)[2], which corresponds to what is internationally propagated (see Deveau et al., 2015[3] and NIOSH, 2017[4]). The draft version of the renewal of the EN 689 standard[5], Annex B also applies this hierarchy. The image below shows the hierarchy.

The Help function provides detailed schemas of the hierarchies used.



Sampling methods

For many chemical substances, methods for measuring the concentrations in the air at the workplace and in biological media are known. The sampling methods and their characteristics, as far as available, are presented in the tab “Sampling Methods”. For the sampling methods, the rich sources of Dutch, European and American organizations are used. Measurement methods are presented per version according to a structured hierarchy.



The harmonized information on the classification and labelling according to the EU-GHS (CLP: Regulation 1272/2008) is presented in the tab “Properties”. If there is no harmonized CLP classification, the classification in the Australian equivalent of REACH/CLP, the NICNAS[6], will be presented. This information includes:

  • H-phrases
  • Hazard classes and Category Codes
  • Icons and Signal Words

For substances without harmonized CLP classification, DOHSBase has developed a system to determine its own classification and labelling assessment (“self-classification”). The following schedule is used[7].

The program clearly states that in a substance with a classification according to the self-classification, this is the assessment of DOHSBase.


Physico-chemical properties

Information on the physico-chemical properties, which is relevant for modelling exposure, is presented in the tab “Properties”. They are collected according to a specific quality hierarchy. The following physico-chemical properties are listed, if known:

  • Molecular Weight
  • Physical State
  • Melting Point
  • Boiling Point
  • Vapour Pressure
  • Saturation Concentration
  • Mass Density
  • Solubility in Water
  • Log Octanol-Water
  • Henry’s Law Constant
  • Lower Explosion Level
  • Flash Point


Compare Mode

The Mode “Compare” allows you to determine the ranking of the potential risk of substances. This is a very useful tool when you want:

  • To conduct a risk assessment of a mixture of chemicals or a workplace with a variety of hazardous substances;
  • Search for less hazardous substances, which are functionally similar (for example for carcinogenic, mutagenic and reproductive toxic substances)
  • To identify the REACH authorization and limitation of so-called ‘Substances of Very High Concern’.


This feature uses from the selected substances:

  • The H-phrase (s);
  • The saturation concentration;
  • The occupational limit value (including kick-off value if there are no formal limit values).
  • The “evaporation capability”. DOHSBase developed a new unique index: the “Threshold exceedance IndeX” (TIX).

The end result is shown in a new index: the “Risk Assessment Score” (RAS). For more information open NVVA Newsletter.april NR1 2006.DOHSBase Compare (in Dutch only).

This feature is extremely useful if you are dealing with a mixture of different substances and you want to identify the most risky ones.




[1] T. Scheffers, G. Wieling (2014). Careful with that DNEL, Occupational Hygienist! BOHS-Exposure June 2014 | Issue 3 |

[2] T. Scheffers, G. Wieling (2014). Presentation on H3##-statement based kick-off levels. Bilthoven, NVT-AT 25-09-2014. Sheet 10. Available at:

[3] M. Deveau, C-P Chen, G. Johanson, D. Krewski, A. Maier, K. J. Niven, S., Ripple, P. A. Schulte, J. Silk, J. H. Urbanus, D. M. Zalk & R. W. Niemeier (2015). The Global Landscape of Occupational Exposure Limits—Implementation of Harmonization Principles to Guide Limit Selection, Journal of Occupational and Environmental Hygiene, 12:sup1, S127-S144.

[4] NIOSH (2017). The NIOSH Occupational Exposure Banding Process: Guidance for the Evaluation of Chemical Hazards. External Review Draft. March 8, 2017. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH). Available at:

[5] EN-689. Workplace atmospheres – Guidance for the assessment of exposure to inhalation to chemical agents for comparison with limit values and measurement strategy. Status: concept/Draft. Expected adoption: 2018.

[6] NICNAS: he National Industrial Chemicals Notification and Assessment Scheme (NICNAS)

[7] Wieling G. (2017). (In Dutch) Presentatie Sessie B Bewezen in de praktijk: nieuwe methoden voor CLP en REACH. Symposium Nederlandse Vereniging voor Arbeidshygiëne, NVvA. Available at: