An overview of values for the threshold of toxicological concern.

An overview of values for the threshold of toxicological concern (TTC) is presented. This comprises the more established TTC values, including those that have been endorsed by regulatory bodies, and those that have more recently been proposed and may still need further development. The overview is structured by use/exposure scenario and provides, in particular, key information on the underlying databases. It is aimed to support the application of the TTC approach in the risk assessment of chemicals whereby it is important to be aware under which circumstances a certain TTC value can be applied. Some recommendations for potential future developments to further improve the TTC approach are also being made.