Comparison of Mechanistic and Semi‐Empirical Two‐Zone Models for Estimating Dust Exposures

PO 101‐1 The Use of Analogous Materials to Assess Historical Exposures ‐ An Example Using Asbestos Cloth Products M. Holton, R. Adams, ENVIRON International Corp., Princeton, NJ. Situation/problem: Asbestos was historically used in over 3,000 unique products. Industrial hygiene exposure data is not available for many of these products. The majority of these products are not in production and the availability of these materials for workplace simulation testing is limited or non‐existent. Resolution: We assembled existing data relating to exposures associated with asbestos cloth production and use in peer‐reviewed literature, governmental documents and unpublished workplace simulations. Asbestos cloth had relatively small variation in asbestos content. Similar materials such as gaskets, packing and friction products have been regularly studied. Exposures associated with asbestos cloth products such as welding blankets, flexible duct connector and laboratory products have been studied less extensively. Quantitative exposure data collected from the worker’s breathing zone, analyzed by a PCM equivalent methodology and information pertaining to sample duration were considered. Data were grouped by activity type and, where sufficient data existed, statistical testing of the variation within and between groups was performed. Where there was insufficient data, a qualitative analysis of exposures was performed. Results: Although there were many unique asbestos containing products, the majority of products were found in a handful of matrices. When looking at products within a specific matrix, it was possible when accounting for factors including fiber type, percent asbestos content, and nature of use, to utilize existing data from analogous products to estimate exposures associated with the use of products for which data does not exist. Lessons learned: The results of this study will provide insight into the ability to use existing data from analogous products to estimate exposure associated with the use of asbestos cloth products. This will also provide information useful for determining the applicability of this methodology to other asbestos containing material matrices.