Developing Health-Based Pre-Planning Clearance Goals for Airport Remediation Following Chemical Terrorist Attack: Introduction and Key Assessment Considerations

Abstract

In the event of a chemical terrorist attack on a transportation hub, post-event remediation and restoration activities necessary to attain unrestricted facility reuse and re-entry could require hours to multiple days. While restoration timeframes are dependent on numerous variables, a primary controlling factor is the level of pre-planning and decision-making completed prior to chemical terrorist release. What follows is the first of a two-part analysis identifying key considerations, critical information, and decision criteria to facilitate post-attack and post-decontamination consequence management activities. A conceptual site model and human health-based exposure guidelines are developed and reported as an aid to site-specific pre-planning in the current absence of U.S. state or Federal values designated as compound-specific remediation or re-entry concentrations, and to safely expedite facility recovery to full operational status. Chemicals of concern include chemical warfare nerve and vesicant agents and the toxic industrial compounds phosgene, hydrogen cyanide, and cyanogen chloride. This work has been performed as a national case study conducted in partnership with the Los Angeles International Airport and The Bradley International Terminal. All recommended guidelines have been selected for consistency with airport scenario release parameters of a one-time, short-duration, finite airborne release from a single source followed by compound-specific decontamination.

Developing Health-Based Pre-Planning Clearance Goals for Airport Remediation Following a Chemical Terrorist Attack: Decision Criteria for Multipathway Exposure Routes

“…As indicated in the plots of liquid CWA persistence on airport interior media presented in the companion paper by Watson et al (2011 , this issue) , it is highly unlikely that non-persistent CWAs will remain on surfaces after decontamination has been performed and verified. However, in cases where natural attenuation or degradation can be anticipated, consideration of surface values becomes extremely important.…”

“…Principal CWA degradation products of interest were previously identified in Watson et al (2011, this issue); available RfDs and RfD e for the principal CWA degradation products are summarized in Table 5.…”

“…In other words, this description encompasses all airport personnel performing tasks other than decontamination of CWAs or TICs. Remediation protocols ( Watson et al 2011 , this issue) require that all of these tasks and services be performed only after obtaining confirmation that (1) the agent source is removed and/or neutralized, (2) all forensic assessment is completed, (3) any decontamination processes are completed and verified, and (4) clearance sampling has characterized atmospheres. The airport response protocol recommends that any subsequent detection of compounds of concern at clearance concentrations would result in the prompt exclusion of personnel until additional remediation occurs.…”

“…This work is presented in two parts: Part I (“Key assessment considerations”) ( Watson et al 2011 , this issue) characterized the airborne release chemical attack scenario at a major U.S. airport that serves as the basis of the evaluation. Scenario assumptions were described, chemicals and populations of concern were characterized, various post-event phases and timelines were summarized, a conceptual site model (CSM) to characterize potential health risks of concern was derived, and precedents and resources were evaluated.…”

“…Detailed project background was provided in Part I of this analysis ( Watson et al 2011 , this issue) and is only briefly summarized here. The DHS, and specifically the DHS Chemical and Biological Countermeasures Program, has been given responsibility to improve domestic preparedness for potential chemical terrorist release incidents at key U.S. transportation nodes.…”