Integration of Industrial Hygiene Statistical Tools Into TSCA Risk Evaluations

Ernest N. Morial New Orleans Convention Center 

In recent years, EPA has released several risk evaluations under the Toxic Substances Control Act (TSCA) covering both consumer and worker exposures and associated risks. EPA has used various sources of exposure data and modeling approaches to characterize these exposures. In some instances, EPA has selected point values from the exposure data to describe exposures rather than using statistical tools to characterize the exposure profile. As a demonstration of the potential application of such statistical tools in enhancing EPA Risk Evaluations for prospective exposure assessments, we present a case study using Expostats with the available consumer and occupational data on exposures associated with vermiculite attic insulation. Vermiculite attic insulation that was historically sourced from the Libby, Montana, vermiculite mine may contain asbestiform amphibole minerals. Homeowners and contractors may continue to be exposed to these amphiboles during disturbance of existing attic insulation. EPA has previously evaluated exposures associated with vermiculite attic insulation under TSCA but relied upon selected exposure values from a single published study. We supplement this exposure dataset with additional published exposure data and perform statistical analysis on the full dataset to update cancer risk estimates and calculate the probability that exposures would exceed the OSHA PEL of 0.1 f/cc and that cumulative exposure would exceed a working lifetime at the OSHA PEL.

J. Lotter, Insight Exposure & Risk Sciences Group, Boulder, CO, USA
B. Roberts, Benchmark Risk Group, Grand Rapids, MI, USA
S. Zentner, Benchmark Risk Group, Grand Rapids, MI, USA
 

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Asbestos, lead, and dust

Exposure Assessment

Regulatory compliance

Risk assessment and management