Skip to main content

EFSA/WHO report makes recommendations on Threshold of Toxicological Concern approach

EFSA and the World Health Organization (WHO) have published a report on the joint workshop they held to review the Threshold of Toxicological Concern (TTC) approach to chemical risk assessment.

The experts who attended the meeting agreed that the TTC approach is fit for purpose as a screening tool to assess low-dose exposure to chemical substances and identify chemicals for which further data are necessary to assess risks to human health.

The meeting made a number of proposals to improve and expand the TTC approach, including a revised decision tree, based on the current state-of-the-science and available toxicological databases.

It also recommended that a permanent repository should be set up for data supporting TTC and the Cramer classification scheme by merging existing databases, using clear inclusion criteria for studies.

A spokesman for EFSA said that the Authority was now considering how best to incorporate the recommendations of the expert group into its risk assessment practice.

The report was finalised following an eight-week online public consultation carried out by EFSA and the WHO.

What is the TTC approach?

The TTC approach is a screening and prioritisation tool for the safety assessment of chemicals when human exposure is estimated as low but hazard data are incomplete. The approach is not applicable when compound-specific assessment and toxicity data are available or are required under existing regulations.

Event report: Review of the Threshold of Toxicological Concern (TTC) approach and development of new TTC decision tree

Outcome of a public consultation on the conclusions and recommendations of the EFSA–WHO workshop on the TTC approach

FAQ: Threshold of Toxicological Concern

How to contact us

EFSA Media Relations Office

Tel. +39 0521 036 149

E-mail: press [at]

(Only if you are a member of the press)

Ask a Question Service

You have a question about EFSA’s work? Contact our Ask a Question service!

Ask a Question Service