Occupational Exposure Limits (DNEL)

A Derived No-Effect Level (DNEL) is a toxicological exposure limit that is needed to be calculated for chemicals in the process of gaining market access in both Switzerland and the EU. Many companies complained that the calculation of DNELs is complicated and time-consuming. The section Chemicals and Occupational Health at SECO provides therefore an Excel spreadsheet, known as the SECO-DNEL Tool, to simplify the correct calculation of DNELs. 

Introduction to Derived No-Effect Levels (DNELs)

Regulation (EC) No 1907/2006 (REACH) requires European manufacturers and importers to establish exposure scenarios for chemical substances produced in or imported into the European Economic Area (EEA) in quantities of ten tonnes per year or more. Swiss companies, which export to the EEA are therefore required to comply with this regulation.

In addition, the Swiss chemicals regulation ChemO (SR 813.11) stipulates that Swiss companies producing for or importing into Switzerland are also required to establish exposure scenarios under certain conditions.

Exposure scenarios describe the conditions of use required to keep risks under control during manufacturing and all identified uses of the substance down the supply chain. The DNEL is used as a reference value to characterise the risk. If exposure during a specific use exceeds the DNEL, the risk is not considered to be adequately controlled. On the other hand, if exposure is below the corresponding DNEL, the risk is considered to be adequately controlled, and that particular use of the substance to be safe under the described conditions.

Definition of DNELs

REACH Annex 1 Section 1.0.1 defines DNELs to be a level of exposure to the substance above which humans should not be exposed. REACH Annex 1 Section 1.4.1 requires that DNELs are to be established for all relevant combinations of

  • population groups (workers, general population, human via the environment),
  • exposure routes (oral, dermal and inhalation),
  • duration of exposure (long-term and short-term) and
  • type of effects (systemic and local).

Examples of DNELs are:

  • worker-DNEL long-term for inhalation route - reprotoxic effects
  • worker-DNEL long-term for dermal route - systemic - other effects

It may be necessary to calculate serval DNELs depending on the relevant exposure patterns and exposure scenarios of concern. For example, a certain substance may adversely impact health through both inhalation and dermal exposure or exposure may affect both workers and the general population.


Calculating DNELs is complicated and prone to errors. We therefore provide a user-friendly spreadsheet to ensure a straightforward derivation of accurate DNELs. Called the «Simple European Calculator Of DNEL», or SECO-DNEL Tool for short, this spreadsheet helps calculating DNELs in accordance with the latest regulatory requirements. It uses the calculation steps stipulated by ECHA Guidance R.8 “Characterisation of Dose [Concentration]-Response for Human Health” (2012). Where possible, substance-specific data should be used to derive DNELs. If no substance-specific data is available, the spreadsheet offers a standard procedure with standard values and factors that comply with the ECHA Guidance R.8.
.It is recommended to check the spreadsheet regularly for updates, as existing DNEL scenarios can be re-evaluated and modified. New developments and scenarios may be incorporated into the spreadsheet as well.
Additional information on calculating DNELs is found in the SECO-DNEL Tool presentation and the user manual.

SECO-DNEL Tool languages

The SECO-DNEL Tool is currently available in German, French, Italian and English. Please contact us if you would like to assist in translating it into additional languages.


The SECO-DNEL Tool is available to download from this page and may be used free of charge. The terms and conditions of the Swiss Federal Administration apply.

System requirements

Windows OS
Microsoft Excel 2007, 2010, 2013
Macros must be enabled
Please note: as the SECO-DNEL Tool is programmed in VBA, it currently cannot be used on Mac computers.


We would like to thank the German Federal Institute for Occupational Safety and Health in Dortmund for their expertise and advisory services in developing the SECO-DNEL Tool as well as UBit in Winterthur, Switzerland, for their technical support.


Contact for SECO-DNEL Tool


ECHA Guidance (2012):

«Characterisation of dose [concentration]-response for human health R.8»

Last modification 18.04.2017

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