Title: Independent analysis of time-varying hydrogen cyanide gas exposures on rats using toxic load-based modelling

Authors: Alexander Slawik; James B. Silva; Kevin C. Axelrod; Jeffry T. Urban; Nathan Platt

Addresses: Institute for Defense Analyses, 4850 Mark Center Drive, Alexandria, VA 22311-1882, USA ' SAS Institute, 10188 Telesis Court #200, San Diego, CA 92121-4779, USA ' McKinsey & Company, 280 Congress Street, Suite 110, Boston, MA 02210-1028, USA ' Institute for Defense Analyses, 4850 Mark Center Drive, Alexandria, VA 22311-1882, USA ' Institute for Defense Analyses, 4850 Mark Center Drive, Alexandria, VA 22311-1882, USA

Abstract: The US Defence Threat Reduction Agency (DTRA) sponsored a two-year set of experiments, conducted in 2012 and 2013, that were designed and executed by the US Army's Edgewood Chemical and Biological Center (ECBC) and the Naval Medical Research Unit Dayton (NAMRU-D) to explore time-varying inhalation exposures of hydrogen cyanide gas on rats. Our analysis, detailed in a separate paper, finds that a single set of fitted parameters for the toxic load model (i.e., the toxic load exponent n, probit slope m, and median lethal exposure TL₅₀) cannot accurately model the single exposure experimental data across the experiments' full range of time from 2.3 to 30 minutes but can on the longer timescales of 10 to 30 minutes. However, none of the toxic load models that we considered fits the experimental data for the novel, time-varying exposures well, with the average concentration and Griffiths-Megson models providing the least inaccurate casualty predictions.

Keywords: casualty assessment; consequence assessment; Haber's law; toxic load modelling.

DOI: 10.1504/IJEP.2019.104879

International Journal of Environment and Pollution, 2019 Vol.66 No.4, pp.267 - 275

Accepted: 26 Apr 2019
Published online: 05 Feb 2020 *

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