Abstract
The European Chemicals Agency (ECHA) has been established to act as an independent body in the context of the implementation of the Regulation on the registration, evaluation, authorisation and restriction of chemicals (REACH) (Regulation (EC) 1907/2006). Quantitative exposure estimates are required for all exposure scenarios where hazardous emissions occur using exposure measurements or exposure models. REACH regulation specifies that exposure models need to be appropriate and quantitative. Here, we evaluated the criteria for regulatory exposure models by ECHA.
MethodsThe evaluation was performed by asking ECHA the criteria for exposure models.
ResultsECHA does not specify any quality criteria for regulatory exposure models or have transparency requirements. Without quality criteria and transparency, there cannot be quality assurance or control. Thus, an appropriate model cannot be defined. ECHA does not recognize the quantitative term even though the fundamental requirement for quantitative exposure assessment is quantitative uncertainty assessment.
ConclusionsAs a result of these shortcomings, ECHA R.14 Guidance for occupational exposure assessment allows the use of non-physical models containing qualitative parameters based on non-accessible calibration databases and statistical evaluations. Because of the lack of transparency, non-physical model construct, and subjective input parameters, model results cannot be associated with real-world operational conditions, and quantitative uncertainty assessment is not feasible. This makes the models qualitative by definition and is not applicable to regulatory exposure modelling. This raises questions about whether ECHA has followed its regulatory mandates in implementing the REACH legislation.
Plain Language Summary
ECHA has a mandate to implement REACH chemical regulation in the European Union. Quantitative exposure estimates are needed for hazardous chemicals' human health risk assessment. Quantitative exposure assessment can be conducted by using appropriate exposure models. However, ECHA does not provide quality criteria for regulatory exposure models in REACH, does not require transparency from the models applied in REACH, nor does it recognize the term quantitative. It is not feasible to conduct quality control or quality assurance without quality criteria or transparency requirements. As a result of these shortcomings, ECHA R.14 Guidance for occupational exposure assessment allows the use of non-physical models containing qualitative parameters based on non-accessible calibration databases and statistical evaluations. This raises logical questions about whether ECHA has followed its mandates in implementing the REACH legislation.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement Nº 101138414 (Multidimensional Integrated Quantitative Approach To Assess Safety And Sustainability Of Nanomaterials In Real Case Life Cycle Scenarios Using Nanospecific Impact Categories [INTEGRANO]).
This work is licensed under a Creative Commons Attribution 4.0 International License.
Amendment
- In addition to transparency, other major problems are that ECHA does not follow international terminology for the quantitative exposure model and the tiered modelling approach.
- Stoffenmanager (StM) and the Advanced REACH Tool (ART) are not considered as screening-level models, in addition to many other models given in ECHA R.14, but quantitative exposure assessment models for regulatory exposure assessment under REACH legislation.
- We have repeatedly asked the Editor to change the article to “Open Letter” from “Research Article”. The Editor finally did this on 6th Nov 2025.
- This work focuses on the regulatory exposure model requirements specified by ECHA. In contrast, the model evaluation for the two higher-tier models, as classified under ECHA R.14, was carried out for StM and ART in Koivisto et al. (2022, 2018), and the response letters by Cherrie et al. (2020) and Fransman et al. (2022) (see references, e.g., from the response letter). In the model evaluation, a systematic literature review was conducted. However, in the current study, we found no literature on the regulatory modelling criteria set by ECHA. This is why communication with ECHA is considered the most reliable and transparent source.
- In methodology, we do not know a better approach to evaluate the regulatory exposure model criteria than open and transparent discussion with ECHA.
All concerns have already been addressed in the previous version of the study and in the last review comments.
We added in the Acknowledgements a statement that “The views expressed in this article are solely those of the coauthors and may not represent those of their organizations.”
