Compilation of Exposure Scenarios

Exposure scenarios must be prepared when a substance is manufactured or imported in quantities of 10 tonnes per year and above and classified as dangerous or as PBT/vPvB. An exposure scenario is a set of conditions that describe how a substance (as such, in a preparation or in an article) is manufactured or used during its life-cycle and how the manufacturer or importer or downstream user controls or recommends controlling exposure of humans and the environment.

An exposure scenario must include the appropriate risk management measures and operational conditions that, when properly implemented, ensure that the risks from the uses of the substance are adequately controlled. Exposure scenarios need to be developed to cover all "identified uses" such as:

• Own uses of the manufacturers, importers or downstream users
• Uses which are made known to the manufacturer, importer or downstream userthat can be included in the assessment

In addition, all life-cycle stages resulting from these uses shall be covered by the assessment, including for example the ‘use’ of an article containing the substance (sometimes referred to as ‘service life’) as well as the waste stage.

Exposure scenarios are also a tool for communicating operational conditions of use and risk management conditions of use through the supply chain as relevant exposure scenarios will be annexed to the Safety Data Sheets that will be supplied to downstream users and distributors.

The development of an exposure scenario is an iterative process which is part of the CSA. Once the registrant or downstream user has identified the relevant uses of his chemical substance he may derive a tentative exposure scenario on the basis of a first set of defined operational conditions of use, risk management measures and local conditions. From this tentative exposure scenario the exposure can be estimated as well as the risk. If it is estimated that a risk might not be adequately controlled then further refinement of either the exposure assessment, eventually including modifications of the operational conditions or risk management measures put in place and described in the exposure scenarios, or of the hazard assessment might be needed until the risks to the environment and the human health are adequately controlled. The output of this iterative process will be the final exposure scenario which will be annexed to the Safety Data Sheet as described before.