B19.2 – Refinement of a framework for extrapolating of worker exposure measurement data

Description

LRI B19.2 is an extension of Cefic-LRI B19 project: ‘Extrapolating the Applicability of Worker Exposure Measurement Data’.

This extension will result in a refined and additionally validated read across framework for which we engage with stakeholders. Also, the project will result in a final report, which includes an executive summary, a description of the study and its results.

In the previous LRI B19 study, five case studies with high quality data were used to test the proof of principle of the framework. The case studies covered a wide variety of different substances such as gasses, respirable dust resulting from abrasion of a solid object, aerosols in complex mixtures, inhalable dust and vapours in complex mixtures. Within these 5 case studies, in total 22 read-across factors, estimated exposures and the confidence intervals were calculated and compared with exposure values. In all cases, the read-across lead to conservative estimates, as calculated exposure values were generally higher compared to actual measured values.

While these case studies showed the proof of principle of the framework, a general consensus was reached that more testing and improvements should be made to refine the framework and reach a general acceptance/ confidence from regulatory, scientific and industry stakeholders.

Objectives

The purpose of the currently proposed extension B19.2 project is to improve on the framework delivered in the previous B19 project, by 1) re-assessing the existing case studies in light of the refined read-across approach, 2) developing further case studies to enable testing of determinants that were not studied in the first phase of the project, 3) further refining the read across approach based on the outcome of the case study results, and 4) seeking further support for the framework from regulatory, scientific and industry stakeholders.

As part of the project and largely also in the final report, the following will be delivered:

1) Selection and demonstration of a set of extra case studies (with multiple parameter combinations) demonstrating the framework, including data with more limited data quality
2) Refinement of the framework based on analysis of the extra case studies, as well as previously used case studies from the B19 project
3) Update of the data quality criteria
4) A full description of the approach, including its domain(s) of applicability and rules.