How clean is clean enough? Recent developments in response to threats posed by chemical and biological warfare agents

Abstract

Recent terrorist events underscore the urgent need to develop a comprehensive set of health-protective cleanup standards and effective decontamination technologies for use in the restoration of civilian facilities. Accurate scientific information remains limited in the area of biological warfare agents. However, new guidelines and calculated cleanup values are emerging for initial re-entry and long-term reoccupation following use of chemical warfare agents. This article addresses airborne, soil, and surface exposures following release of G-type chemical warfare agents and VX. Cleanup goals should be tailored to the type of population that may be exposed, potential exposure times, and other scenario-specific considerations. Three different airborne concentrations are proposed for cleanup of public sector facilities. One value is recommended for initial re-entry; a more conservative value is recommended for long-term monitoring and increased public confidence; and a third, even more conservative concentration represents essentially a no-effect level for round-the-clock airborne exposure. Health-based cleanup levels are provided for contaminated residential and industrial soil. Results are presented on the outcome of a preliminary risk assessment to determine safe surface levels (e.g., walls, floors, and handrails) for cleanup after exposure to the G agents and VX. Because specific cleanup criteria for most biological warfare agents remain problematic, recommendations are made for filling the knowledge gaps.

An Approach to the Study of Transport and Dispersion of Threat Agents in a Subway Station

“…In the event that this data is not available (Raber et al, 2004), the risk of exposure will be assessed rather than the risk of disease outcome (Arnot et al, 2006). For each of the PIV experiments conducted, BCA concentrations measured as a function of space and time will be compared.…”

Predicting Response to Reassurances and Uncertainties in Bioterrorism Communications for Urban Populations in New York and California

“…51,53,54 Differences along these dimensions have important implications for dynamic risk communication because they may influence the ongoing interpretation or reinterpretation of crucial information during an evolving emergency, shape information needs, and affect response to recommended or mandatory self-protective guidance and the timeliness of personal actions. 28,50,55,56 Vulnerability and potential for loss during acts of WMD terrorism or other extreme incidents may be elevated as an event progresses if risk communications do not resonate or are incompatible with expectations, life circumstances, personal/community resources, values, information needs, and personal evaluation of risk circumstances. 18,20,21,27,28 According to recent risk analyses, 51 extreme events present an unequal potential for loss, not only because of preexisting vulnerabilities in terms of social, resource, and environmental factors, 27,28,30,40 but also because of differences in trust and the potential influence of distrust of government or leaders.…”

Interim Consequence Management Guidance for a Wide-Area Biological Attack

“…Most researchers writing on the topic agree that there is currently insufficient information to develop an -infectious dose‖ and to quantify a -safe‖ amount of residual biological agent in a decontaminated facility or outdoor environment (see for example Rubin 1987;Haas et al 1999Haas et al , 2002Meselson 2001;Peters and Hartley 2002;NRC 2005;Raber et al 2004;and Lucey 2005). In the event of wide-area biological contamination, any clearance goal will need to address and incorporate incident-and site-specific parameters and conditions.…”

“…Considerable research has been conducted on identifying suitable standards for cleanup and reoccupancy following a B. anthracis attack (Raber , 2004Simpson 2005;Canter 2005; see also Section 6.5). If risk is framed in terms of expected illnesses or deaths, then it should be straightforward to examine the risk and determine whether remediation is necessary.…”