EPA 600/R-12/516 | May 2012 | www.epa.gov/ord Decontamination of Indoor and Outdoor Materials with Aqueous Chlorine Dioxide Solutions Office of Research and Development National Homeland Security Research Center EPA/600/R/12/516 May 2012 Decontamination of Indoor and Outdoor Materials with Aqueous Chlorine Dioxide Solutions U.S. Environmental Protection Agency Research Triangle Park, NC 27711 ii Disclaimer The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development’s (ORD) National Homeland Security Research Center (NHSRC), funded, directed and managed this work through Contract Number EP-C-10-001 with Battelle. This report has been peer and administratively reviewed and has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use of a specific product. Questions concerning this document or its application should be addressed to: Joseph Wood National Homeland Security Research Center Office of Research and Development U.S. Environmental Protection Agency Mail Code E343-06 Research Triangle Park, NC 27711 919-541-5029 iii Foreword Following the events of September 11, 2001, addressing the critical needs related to homeland security became a clear requirement with respect to EPA’s mission to protect human health and the environment. Presidential Directives further emphasized EPA as the primary federal agency responsible for the country’s water supplies and for decontamination following a chemical, biological, and/or radiological (CBR) attack. To support EPA’s mission to assist in and lead response and recovery activities associated with CBR incidents of national significance, the National Homeland Security Research Center (NHSRC) was established to conduct research and deliver products that improve the capability of the Agency and other federal, state, and local agencies to carry out their homeland security responsibilities. One goal of NHSRC’s research is to provide information on decontamination methods and technologies that can be used in the response and recovery efforts resulting from a CBR release over a wide area. The complexity and heterogeneity of the wide-area decontamination challenge necessitates the understanding of the effectiveness of a range of decontamination options. In addition to effective fumigation approaches, rapidly deployable or readily available surface decontamination approaches have also been recognized as a tool to enhance the capability to respond to and recover from such an intentional CBR dispersion. Through working with ORD’s program office partners (EPA’s Office of Emergency Management and Office of Chemical Safety and Pollution Prevention) and Regional on-scene coordinators, NHSRC is attempting to understand and develop useful decontamination procedures for wide-area remediation. This report documents the results of a comprehensive laboratory study designed to better understand and maximize the effectiveness of aqueous solutions of chlorine dioxide (ClO2) to decontaminate materials contaminated with Bacillus anthracis spores. These results, coupled with additional information in separate NHSRC publications (available at www.epa.gov/nhsrc) can be used to determine whether a particular decontamination technology can be effective in a given scenario. NHSRC has made this publication available to the response community to prepare for and recover from disasters involving biological contamination. This research is intended to move EPA one step closer to achieving its homeland security goals and its overall mission of protecting human health and the environment while providing sustainable solutions to our environmental problems. Jonathan Herrmann, Director National Homeland Security Research Center iv Acknowledgments Contributions of the following individuals and organization to this report are gratefully acknowledged: United States Environmental Protection Agency (EPA) Office of Research and Development, National Homeland Security Research Center Eletha Brady-Roberts (Quality Assurance) Lukas Oudejans (peer review) United States Environmental Protection Agency (EPA) Office of Emergency Management, National Decontamination Team Michael Ottlinger (peer review) United States Environmental Protection Agency (EPA) Office of Research and Development, National Risk Management Research Laboratory Timothy Dean (peer review) Battelle v Executive Summary The U.S. Environmental Protection Agency quantified in terms of log reduction, based (EPA), Office of Research and Development on the difference in the number of bacterial is striving to protect human health and the spores recovered from the positive controls environment from adverse impacts resulting and test coupons. Efficacy tests were from acts of terror by investigating the conducted with increasing levels of ClO2 effectiveness and applicability of (1,500 to 4,000 parts per million (ppm)), technologies for homeland security (HS)- contact times (one or two hours) and/or related applications. The purpose of this number of spray applications (two to four investigation was to determine the total spray applications), in order to decontamination efficacy of aqueous maximize the decontamination efficacy for chlorine dioxide (ClO2) solutions in each material (i.e., to achieve a target log inactivating Bacillus anthracis (causative reduction of at least 6.0). In addition to agent for anthrax) spores, as a function of efficacy, the impact of the decontamination material and decontamination parameters process on the materials was visually (concentration, contact time, number of observed and reported. spray applications). The objective of this study was to provide an understanding of the Summary of Results performance of the aqueous ClO2 The aqueous ClO2 decontamination decontamination technology to guide its use technology provided complete inactivation and implementation in HS applications. In of B. anthracis spores on galvanized metal, the assessment of options for decorative laminate, and glass using a 3,000 decontamination following intentional ppm, three-spray, one-hour contact time release of B. anthracis, it is important to treatment. Complete decontamination was know whether and to what extent such not achieved for any of the other materials factors can impact the decontamination for any of the ClO2 decontamination efficacy. conditions tested. The highest average log reductions achieved for B. anthracis on This investigation focused on treated wood, industrial carpet, and decontamination of both indoor and outdoor unpainted concrete were 2.64, 3.40, and materials, including industrial carpet, treated 2.50, respectively. The aqueous ClO2 wood, unpainted concrete, two types of soil decontaminant was the least effective on the material (topsoil and Arizona Test Dust soil materials (topsoil and AZTD), with [AZTD]), decorative laminate, galvanized nearly all log reduction results less than 1.0 metal, and glass. Decontamination efficacy for the six ClO2 conditions tested. Overall, tests were conducted with spores of Bacillus the results show that with robust enough anthracis or Bacillus subtilis, the latter conditions (i.e., 3,000 – 4,000 ppm ClO2, organism included to assess its potential as a one-two hour contact time, and two – four surrogate for future studies related to B. spray applications), the aqueous ClO2 spray anthracis. Decontamination efficacy was technology may be an effective vi decontaminant for some nonporous materials such as glass, galvanized metal, and laminate. However, aqueous ClO2 was found to be largely ineffective on porous materials (e.g., wood, carpet, soils, and concrete), even under the most robust conditions tested. With regard to comparing the decontamination efficacies of B. anthracis and B. subtilis, there were no test results in which B. subtilis was inactivated to a significantly greater degree than B. anthracis. Additionally, no visible damage was observed on any test materials for any of the decontamination conditions tested. vii Contents Foreword ................................................................................................................................................... iv Acknowledgments...................................................................................................................................... v Executive Summary .................................................................................................................................. vi Tables ........................................................................................................................................................ x Figures..................................................................................................................................................... xiii Abbreviations/Acronyms ........................................................................................................................ xiv 1.0 Introduction ........................................................................................................................................ 1 2.0 Preparation of ClO2 Solutions and Test Matrix .................................................................................. 2 2.1 Preparation of Aqueous ClO2 Solutions .................................................................................. 2 2.2 Test Matrix ..............................................................................................................................