How to assess risks and set priorities?
Chemicals risk assessment is the core action to identify the ways in which the use of a chemical is problematic. It is the basis to decide upon the urgency of action and identify effective and efficient options to act.
According to standardised methodology at EU level:
A substance causes a risk if the exposure to that substance exceeds the threshold above which adverse effects are expected.
This is expressed with the following equation:
The effect thresholds are as follows:
- Derived no effect level (DNEL) = dose above which an adverse human health effect is expected
- Predicted no effect concentration (PNEC) = concentration above which an adverse effect is expected for the environment
These values are specific for one substance and may be provided in the SDS of the substance or the mixture it is contained in. They may also be available from the ECHA’s database on registered substances.
Please note that this information is not normally available for substances, which are manufactured or imported below 10 t/a per manufacturer/importer. This is due to the absence of a requirement to derive these values for substances in lower volumes. In the event that DNELs/PNECs are missing, analogue values from other legislation, such as workers protection in the EU (OELs) or reference values from the US and Canada, etc. may be researched and used. If no values are available, a quantitative risk assessment is not possible.
DNELs and PNECs need to be selected in accordance with the assessed exposure pathway: if risk from inhalation is assessed, the DNEL for inhalation must be used. DNELs and PNECs may not be available for all exposure pathways.
What are the main risk assessment methods?
Generic risk approach – substances of very high concern
Substances of very high concern (SVHC) can cause very serious, irreversible effects. Moreover, some of them do not have an effect threshold, i.e. no dose or concentration can be determined below which there is no effect. This may be the case for mutagens and carcinogens as well as endocrine disrupting chemicals.
In the case of some SVHCs, exposure cannot be controlled. Such is the degree of their persistence that they accumulate in the environment and the food chain and may eventually reach concentrations where adverse effects occur. This is the case for PBTs/vPvB and PMTs/vPvMs.
For both types of chemicals – non-threshold substances and persistent substances – no quantitative risk assessment can be carried out. Instead, as a default course of action, emissions of these substances should be minimised as much as possible.
Any SVHCs, including non-persistent threshold substances, are a source of concern due to the severe environmental and health effects they may cause. The concept of “zero emission” is unrealistic, because all uses of chemicals cause some emissions. As a result, the EU has set the goal of an eventual phase-out of these chemicals and their replacement with safer alternatives, as soon as possible and whenever feasible.
As is the case with any chemical, the use of SVHCs entails emissions. Therefore, any emission/exposure of SVHCs is a matter for concern due to the severe environmental and health effects that may result. Despite this, current regulations do not stipulate detailed exposure assessment of SVHCs. As a result, at least in the case of consumer products, the only guidance currently available can be found in the conclusions of generic risk assessments regarding the risks posed by using SVHCs.
Quantified risk assessment
In general, risk assessments can be carried out for all substances that are not persistent and do have an effect threshold, because the comparison of DNEL/PNEC with an exposure level is mathematically possible.
Chemical risk assessments can have different scopes, for example:
- Workplace risk assessments aim to identify if workers are at risk from all the chemical agents that are present at one specific workplace.
- Assessments to meet the requirements of the General Product Safety Directive (respectively its national implementation) check if consumers, during normal and foreseeable use of a product, are at risk from the contained chemicals.
- Chemical safety assessments under REACH cover all lifecycle stages and aim to identify any potential risk to consumers, workers and the environment.
- Sustainability assessments not only consider all the chemical risks of a substance, but also evaluate its other environmental as well as social and economic impacts.
- Your company is legally obliged to conduct workplace risk assessments. Therefore, you need to find out if precautionary measures are needed to protect your workers.
Assessment of chemical risks throughout the life cycle
If you plan to substitute a substance in your mixture, it is important that you compare different alternatives and conduct a holistic risk assessment for the entire lifecycle and all the subjects of protection (workers, consumers and the environment).
If your alternatives are also chemicals (i.e. a drop-in solution or 1:1 substitution), the conditions of use throughout the lifecycle may:
- Be very similar if the replacement chemical does not change the main characteristics of the product and how it is processed. In this case, it is sufficient to compare the hazards and the mobility (vapour pressure, water solubility, dustiness etc.) of the substances to identify which alternative is better than another.
- On the other hand, the conditions may differ significantly, e.g. if a solvent based paint is re-designed to become a water-based paint, where both the application and the curing / drying process of the paint may have to be significantly changed after substitution.
An assessment of the conditions of use is needed to characterise and compare the exposure and risk levels arising from the use of your mixture. This requires assessing risks not only at your production site, but also for all subsequent lifecycle stages.
As you are unlikely to know the specific conditions of use at your customers’ site s or further downstream, you may use tools and default assumptions for the exposure assessment. We recommend using the “ECETOC TRA” tool for an initial risk assessment.
Setting priorities
Prioritisation may necessitate considering different criteria, which are specific to your company’s policy. Compliance with legislation is always the highest priority.
A two-step prioritisation process is as follows:
Based on hazard and qualitative risk considerations and exposure.
The more hazardous a substance is, the more urgently it should be avoided. Apart from ranking chemicals according to their hazards, you should consider your company’s chemicals policy: if there is a target to reduce the use of EDCs, then these types of hazards should receive the highest priority for action.
Exposure – the concentration of a hazardous substance in the mixture can be used as a prioritisation criterion, because the concentration may change the urgency with which action is required, especially for human health hazards.
Further exposure-based criteria could relate to:
- The amounts of a substance that you use in your processes.
- The user group, where any exposure of vulnerable groups, such as children, would increase the priority for action.
- The type of use, where uses with high exposure potential would increase the priority for action.
- For chemicals produced exclusively for professional use, you should ask yourself if protection for workers exists, and if so, whether or not this reduces the priority for action.
The result of second step might modify the initial priorities.
Substitution is the most far-reaching option, and the availability of safer alternatives should always be assessed. This would include evaluating drop-in solutions as well as changes of processes and materials, which might require different manufacturing equipment, etc.
If alternatives or other risk management measures are available, a substitution action could be implemented, which might increase the priority to act. If alternatives to the use of a substance are not easily available, costly or lead to the reduction of product performance, the need for action remains but other cases may be prioritised, where solutions exist, and action is possible.
There are three different types of action that one could take to reduce the risks arising from the use of a chemical besides technical feasibility or any case-specific factors that may influence decision making.
Overview of options to act and the pros and cons of their consequences
| Option to act | + | – | Comment |
|---|---|---|---|
| Redesign product, i.e. either use another material, or eliminate the (need for a) product part or material | Substance usage can be avoidedProof of compliance possible based on inventory Clear communication possibleA good marketing opportunityNeed for future action preventedOpportunity to innovate and change several aspects | May significantly change product appearance and performance, potentially resulting in loss of clientsHigh resource input for a new design phase | Mainly applicable in regard to the physical form of a product; other redesign is substitution |
| Stop marketing / production | Can be implemented immediatelyNo investments needed | Loss of income and clients | Relevant option for products that ‘do not sell anyway’ and/or several aspects of which are identified as critical |
| Substitute with (less harmful) chemicals | Substance usage can be avoided Proof of compliance possible based on inventory Clear communication possible A good marketing opportunityNeed for future action prevented | Substitution may require substantial human and financial resources, and timeUnclear if the quality of the product can be maintainedUncertainties may result due to new suppliers, warranties, etc. | Benefits depend on the alternativeRegrettable substitution to be avoided |
More resources
The ECHA’s tool to conduct a chemical safety assessment according to REACH; it is designed for individual substances but not mixtures.
The Excel-based tool makes it possible to calculate chemical risks and was designed for use by the registrants under REACH.
ChemSelect is an online application that supports the sustainability assessment of substances and mixtures. Based on 9 criteria, you can create a sustainability profile or compare different substances and mixtures with each other. It is designed for small and medium size enterprises using chemicals in their processes and products. ChemSelect can be used with basic knowledge on chemicals (i.e. you should know safety data sheets and understand the main content). The tool is free of charge and can be used intuitively and some instructions are included in the tool itself (top navigation). ChemSelect is available in different languages.