Exposure Factors Interactive Resource for Scenarios Tool (ExpoFIRST), Version 2.1

ExpoFIRST – the Exposure Factors Interactive Resource for Scenarios Tool – brings EPA’s Exposure Factors Handbook: 2011 Edition (EFH) data and the more recent 2017-2019 chapter updates to an interactive tool that maximizes flexibility and transparency for exposure assessors.

ExpoFIRST represents a significant advance for regional, state, and local scientists in performing and documenting calculations for community and site-specific exposure assessments. ExpoFIRST replaces manual calculation and documentation and allows users to draw on data found in the 2011 EFH. The tool stores more than 8,000 values extracted from more than 75 of the most commonly used tables in the EFH. It allows flexibility in scenario design and automates the documentation of algorithms, exposure parameters, and exposure dose estimates. ExpoFIRST is intended to replace the 2004 Example Exposure Scenarios report and complement the 2014 Child-Specific Exposure Scenario Examples report.

The purpose of ExpoFIRST is to allow users to draw on data found in the 2011 Exposure Factors Handbook: 2011 Edition and its updates to develop user-defined scenarios based on route of exposure, medium, receptor(s), timeframe, and dose metric for a contaminant of concern. Assessors can then modify initial parameters as appropriate to account for assessment-specific knowledge and use the tool to calculate deterministic exposure estimates as point estimates. ExpoFIRST allows users to define an unlimited potential scenarios for various receptor populations and life-stages.

ExpoFIRST was developed using Microsoft Access and Visual Basic for Applications (VBA).


Jun 2015EPA completed an internal review.
Feb 2016EPA released the application for an external letter review.
Sep 2016EPA released the final report and Access DB tool.
Apr 2018Released an update (version 2.0) of the Access DB file.
2017 - 2019EPA released updates to chapters 5 (Oct 2017) , 11 (Jun 2018), 12 & 19 (Jul 2018), 9 (Aug 2018), and 3 (Feb 2019)
Jun 2019Released an update (version 2.1) of the Access DB file.

This document has been reviewed in accordance with U.S. Environmental Protection Agency policy and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.