TR 093 – Targeted Risk Assessment


TR 093 : Targeted Risk Assessment | January 2005

One of the key challenges of the proposed European chemicals legislation (REACH) is that it envisages the registration and evaluation of approximately 30,000 chemicals by producers and importers over the next 10-15 years. Faced with such a challenge, both practically and scientifically, appropriate prioritisation will be a key element of the REACH process. To facilitate such work, ECETOC has developed a tiered (step-wise) approach for identifying and prioritising scenarios where risks to human health and the environment from chemicals might reasonably be expected to be high enough to undertake a more detailed assessment of risk. The general concept of ECETOC’s targeted risk assessment (TRA) is based on the premise that depending on both the degree of exposure and the hazard – considered together – different information requirements will be needed to demonstrate safe and responsible production and use of a given chemical.

The concept applies a tiered, or iterative, approach to risk assessment, consisting of three phases, i.e. Tiers 0, 1 and 2. According to this approach, the level of refinement and detail of the information required for a risk evaluation are proportional to the potential risks of a chemical, based on the consideration of both hazards and exposures together, rather than in isolation.

The process also considers existing (and new) risk reduction measures to control exposure.

The core objectives behind the approach are:

  • To target assessment resources on those production and use scenarios of chemicals that constitute a likely concern for man and/or the environment;
  • to ensure that all decisions are based upon risk and account for all relevant information required to reach any soundly-based judgement;
  • to simplify yet maintain the scientific integrity of the risk assessment process;
  • to be consistent with the requirements of existing European health and environmental legislation.

ECETOC’s TRA achieves its objectives by adopting a tiered structure:

Tier 0: The aim of the Tier 0 is to ‘screen’ chemicals and conditions of no immediate concern out of the process, because their general exposure and hazard potential are low, and to identify those other chemicals and conditions where further targeting risk assessment is required. The process used is straightforward, well documented and conservative.

Tier 1: Chemicals and conditions which are not screened out at Tier 0 are evaluated in the Tier 1. The aim of Tier 1 is to use information on uses, exposure scenarios and hazard to carry out a more refined risk assessment to separate the production and uses of no immediate concern from those that require a more detailed investigation. The process necessarily involves co-operation between producers and downstream users to identify key exposure scenarios. It is also designed to be relatively simple and well defined, in line with the common EU risk assessment principles, and aligned with the occupational, consumer and environmental legislation.

Tier 2: Scenarios identified as being of potential concern at Tier 1 proceed to a detailed risk assessment at Tier 2. This assessment is consistent with the established EU risk assessment principles, and enables final risk assessment conclusions to be reached for those scenarios.

The advantages of the approach may be summarised as:

  • It allows a systematic screening of chemicals and their uses for their possible risks, considering hazards and potential exposures together;
  • the available or generated information allows chemicals and uses that are of no immediate concern to be identified quickly and easily and gives priority to the chemicals and uses that require a more detailed evaluation;
  • it uses an increasing level of refinement and detail of the information (both on exposure and hazard) and allows for iteration to account for available risk management measures;
  • the data and resource demands will consequently be proportionate to the likely risks of the chemical, and target the available resources to scenarios of possible concern;
  • using risk assessment as the basis for defining additional information needs through targeting and exposure-driven testing encourages the appropriate use of resources and respects animal welfare;
  • it helps manufacturers and the authorities to make a choice between generation of further information or implementation of more stringent risk reduction measures;
  • it can be used to perform a chemicals safety assessment (CSA) and provide input for a chemicals safety report (CSR).

The concepts of the approach have been programmed into a web tool that integrates the core concepts into an easy-to-use format. The web tool has been shown to work across a range of chemicals and conditions using information and/or data that are readily available and without the need for extensive animal test data requirements or a high level of expertise. The web tool can be found at