The REACH Regulation is based on the principle that it is for the industry to ensure that the substances they manufacture, place on the market or use do not adversely affect human health and the environment.

A chemical safety assessment (CSA) is required for all substances subject to registration under REACH in quantities exceeding ten or more tonn/years. The CSA chemical safety assessment plays a major role since it is the instrument to ensure that all risks are identified and under control.

The Exposure Scenario is a set of conditions that describe how a substance is manufactured or used, and the measures necessary to control exposure to humans and environmental emissions.

The CSR is Chemical Safety Report, the instrument to record and doumentare chemicals.


The Chemical Safety Assessment (CSA) is the process that identifies and describes the conditions under which the manufacturing and use of a substance is considered to be safe.

There are three major steps in the CSA process. These are:

1. HAZARD ASSESSMENT- collection and evaluation of all available data.

The CSA starts with the hazard assessment. The assessment normally comprises the following steps:

  1. INFORMATION GATHERING AND EVALUATION - Under REACH, the registrants are obliged to collect all relevant and available information on the intrinsic properties of a substance. This includes all physicochemical, toxicological and ecotoxicological. The registrant needs to evaluate this information for its quality, including its reliability, relevance and adequacy for hazard assessment. The information should also be evaluated for its completeness, depend on the tonnage manufactured or imported every year. The collection and evaluation of the information on the intrinsic properties of a substance is a general requirement for registration under REACH, not only for substances for which a CSA is required.

  2. HAZARD IDENTIFICATION - the registrant needs to assess and integrate all the available information and determine the capacity of the substance to cause adverse effects to human health and the environment. The identification of the physicochemical hazards will entail the evaluation of the capacity of the substance to produce a dangerous event (explosion, fire, etc.). The registrant is also required to identify the toxicological and ecotoxicological hazards and determine for each adverse health and environmental effect and the dose of use for the negative efects on healt and the environment.

  3. CLASSIFICATION AND LABELLING - Substances and preparations can be classified in different categories of danger (very toxic, toxic, harmful, corrosive, etc.) depending on the hazards identified for human health and the environment. The determination of the appropriate classification has to be documented both in the registration technical dossier and in the CSR. The classification of a substance as dangerous is a critical input in the CSA process since, together with the results of the PBT and vPvB assessment, it will determine the need to carry out an exposure assessment and risk characterisation.

  4. DERIVATION OF THRESHOLD LEVELS - Based on the hazard identification, the registrant will define, where possible, the threshold levels for exposure below which risks for human health and for the environment are considered to be controlled. The Derived No-Effect Level or DNEL measures the potential of the substance to cause adverse health effects, this potential will vary depending on the population likely to be exposed to the chemical, ( workers, consumers or humans), on the frequency and duration of the exposure, on the route of exposure. The DMEL is a semi-quantitative value, represent exposure levels where the likelihood that the identified adverse effect occurs in a population is sufficiently low to be of no concern. The Predicted No Effect Concentration or PNEC is the concentration of a substance in any environment below which adverse effects will most likely not occur during long term or short term exposure. The PNEC needs to be determined for each environmental sphere (aquatic, terrestrial, atmospheric, sewage treatment, food chain). It may not always be possible to derive a DNEL, DMEL or PNEC so If you need risk characterisation in the CSA, it will have to be based on a qualitative analysis

  5. PBT vPvB - PBT substances are substances that are persistent, bioaccumulative and toxic while vPvB substances are characterised by a high persistency and a high tendency to bioaccumulate, but not necessarily by proven toxicity. Experience with these substances has shown that they can give rise to specific concerns due to their potential to accumulate in parts of the environment and to the unpredictability of the effects of such accumulation in the long term.

Where the hazard assessment shows that the substance meets the criteria for classification as dangerous, it will be carried out an exposure assessment which will assess the levels of exposure. If the substance does not meet any criteria of dangerousness exposure assessment will not be required.

2. EXPOSURE ASSESSMENT - The exposure assessment is the process of measuring or estimating the dose or concentration of the substance to which humans and the environment are or may be exposed, depending on the uses of the substance.

An assessment needs to cover the production, all identified uses of the substance and the phases of the life cycle resulting from such use. Also includes the waste stage, and if the service-life of articles containing the substance. The exposure assessment consists of the following two phases:

  1. DEVELOPMENT OF EXPOSURE SCENARIOS - An exposure scenario is a set of information describing the conditions of manufacturing and use of a substance that may give rise to exposure to humans and/or to the environment. These conditions include: Operational conditions, (duration and frequency of use, amount of substance employed, concentration of substance in a product and process temperature.). -Risk management measures (such as local ventilation, air filtering systems, waste water treatment and personal protection equipment.). The risk can be demonstrated to be under control, the exposure scenario can be defined as the set of information describing the conditions under which the risks associated with the manufacturing and the identified uses of a substance can be controlled. It defines the operational conditions and risk management measures required to ensure the safe use of the substance for each exposed population . The exposure scenario plays a core role within the CSA process. It constitutes the basis for the exposure estimation but it is also the major risk communication tool in the supply chain, together with the safety data sheet. The exposure scenario uses o fuse descriptor system. The use descriptor system is based on four elements: sector of use, chemical product category, process category and article category.

  2. EXPOSURE ESTIMATION - Exposure estimation needs to be performed for each of the exposure scenarios under development until the final exposure scenario is defined. When estimating exposure, all human populations liable to exposure and all environmental spheres for which exposure to the substance is known, need to be addressed. Ideally, the process for estimating exposure should be based on actual measurements of exposure. . When estimating human exposure to a substance, all the possible exposure patterns arising from an exposure scenario have to be considered. This implies that for each population, each frequency and duration of exposure and each possible exposure route, you need to determine a level of exposure. Similarly, to be determined is an exposure level for each environmental sphere, both locally and on a regional scale.

3. RISK CHARACTERISATION - Risk characterisation the exposure levels with the levels of each effect threshold are compared at this stage.

The exposure values will be compared with their respective threshold levels (DNEL/DMEL or PNEC) in the risk characterisation. Where no threshold level is available, a qualitative risk characterisation will be required.
The risk characterisation needs to be carried out for each exposure scenario in order to determine if the operational conditions and risk management measures ensure control of risks of the substance.

  1. RISK CHARACTERISATION FOR PHYSICOCHEMICAL PROPERTIES - Substances will be assessed for their explosivity, flammability and oxidising potential. The assessment will include an analysis of the processes in which the substance is used and a description of the measures taken to prevent an accidental release or negative health effects in case of an event.

  2. RISK CHARACTERISATION FOR HUMAN HEALTH - The quantitative risk characterisation for human health is carried out by comparing the estimated exposure level for a given exposure pattern with the lowest DNEL/DMEL value. The comparison needs to be done for each exposure pattern resulting from a given exposure scenario. When no DNEL/DMEL is available for a health effect, a qualitative risk characterisation for that effect will be requie, the aim is to assess the likelihood that adverse effects are avoided.

  3. RISK CHARACTERISATION FOR THE ENVIRONMENT - The quantitative risk characterisation for the environment is carried out by comparing the Predicted Exposure Concentration (PEC) with the PNEC. This is done separately for each environmental sphere, both at a local and regional scale. When no PEC or PNEC can be derived, a qualititative risk characterisation should be conducted. This may be the case for PBT and vPvB substances for which no PNEC can be derived for any environmental sphere. Operational conditions and risk management measures will be directed to minimise emissions and exposure to the environment.

  4. COMBINED EZPOSURES - The risk characterisation also needs to consider risks from combined exposures via different routes or via different sources. This may be the case where the same person is potentially exposed to the same substance via different routes


The risk characterisation will determine if the risk to humans and the environment is under control or not for a given exposure scenario. Risk will be considered to be adequately controlled if:


The chemical safety report documents the chemical safety assessment undertaken as part of the REACH registration process, and is the main source from which the declarant party to provide information to all users of chemicals through the exposure scenarios. It also provides a basis for other REACH processes such as substance evaluation, authorization and restriction.
The chemical safety assessment is carried out to demonstrate that the risks from exposure to a substance in the course of its manufacture and use, are checked when you apply specific operating conditions and risk management measures. These terms of use of a substance constituting the exposure scenario.
The chemical safety report should be easily understood in all its parts as stand-alone document and should include all relevant information for the chemical safety assessment. The principles applied in the risk assessment and exposure, the assumptions made and conclusions drawn should be transparent and well documented.


Experts CEPRA srl. have extensive experience in the field of risk assessment / management and are the ideal partner to guide you through the critical aspects of the preparation of the CSR.