Dealing with an airborne toxin

Immediate evacuation is not always a best practice response to accidental chemical plumes or other non-nuclear airborne hazard releases. Not only is it challenging to initially notify and direct the potentially affected populations, but issues such as the safest direction to evacuate (if any), population density, and type of toxic agent are situation-specific and in some cases require minute to minute meteorological information to be valid. Follow-up instructions for these populations are as important as the initial notification, but are frequently taken for granted or omitted in Emergency Response Plans.

Oak Ridge National Laboratory has defined four levels of sheltering: Normal, Expedient, Enhanced, and Pressurized.[1]

Only the first two levels are commonly available. The above study states that the effectiveness of sheltering in place is subject to

  1. the behavior of the public;
  2. the characteristics of the structure and its immediate environment; and
  3. the characteristics of the toxin. NRS concludes that there are a number of other critical elements to be considered, as well.

Guidelines for SIP must be specifically drawn for each threat. A weighted multi-dimensional Decision Matrix can be developed using event-specific parameters. Visually, this matrix would resemble the famous Rubix cube. Some of the parameters that would be included in such a decision process would be:

I.  Effectiveness of Notification and Update Methods

  • How much lead time is needed to reach populations?
  • How much lead time is needed to allow populations to follow emergency measures?
  • How to will notification of SIP and of the All Clear or Continued Caution be delivered?
  • How and how often should updates be made – minutes, hours, days?
  • U.S. populations are diverse and should be warned in different ways and languages.
  • Information must be communicated in a convincing and directed manner.
  • Overuse of almost every form of communication can cause outages.

II.  Education of Population and Media

  • FAQs sheets are effective if read prior to an event.[2]
  • Simple signage is helpful.[3]
  • What percentage of the population is prepared with Go-Kits?[4]
  • Does the at-risk population have duct tape, towels to wet, and plastic sheeting?[5]
  • Video instruction is available.[6]
  • Experience from past disasters can educate.[7]
  • Some people will not remember siren patterns and certain individuals will be prone to panic.
  • Some people are motivated by fears and distrust of authority and will not voluntarily follow direction.
  • Dispersed families will respond differently from united families.[8]
  • Parents rushing to schools to retrieve children rarely obey instructions, as was seen in the 1999 Chevron refinery explosion.
  • Media reporters often mistake emergency terms. SIP has been confused by the media with the opening of community shelters, resulting in dangerous circumstances and wasted time.

III.  Education of Emergency Response teams

  • People will respond to family before job obligations.
  • If response teams’ families are unprotected, team effectiveness will be reduced.
  • Handicapped or incapacitated individuals may require direct intervention.
  • Risks are more severe for the sick, elderly, and very young.

IV.  Meteorological Data

  • Is it raining? Phosphorus chloride and rain can create a hydrochloric acid cloud.
  • Is it snowing? Visibility of warning signs may be limited.
  • Is it icy? Sirens may be muffled or non-operational.
  • Which direction will the wind carry a hazardous cloud?

V.  Presence of Additional Threats

  • Frequently more than one chemical or hazard will be present during an event.
  • Some airborne hazards are the result of a fire, an explosion, or an accident.
  • The progress of firefighting may be impeded by airborne hazards, allowing residents who are sheltering in place to be at an increased fire risk.

VI.  Population Density

  • How many people are present in a building during an SIP event?
  • Are there hospitals, schools, corrections facilities, half-way houses, homeless shelters, hotels, or large businesses in the path of the airborne hazard?
  • Was a large outside meeting, such as a baseball or football game in progress before the event?
  • Where do people gather who learn of the event while outside?

VII.  Road Conditions and Transportation issues

  • Traffic volume and the presence of emergency vehicles in the case of an accident may alter expected traffic patterns.
  • Transported hazardous materials in a truck or train accident may result in fleeing residents facing chemical exposure in a traffic jam.
  • What are the safest ways to shelter-in-place in a vehicle?
  • Is mass transport present?
  • Are people riding mass transport during the event?
  • How should traffic behave in departing the area of an event?
  • Where should people trapped in rush hour traffic shelter in place?
  • Are roads clearly marked?

VIII.  Time (Season, Daylight) of Event

  • Are people sleeping?
  • Will notification reach them if they are asleep?
  • Are homes and other buildings closed up for cold weather or generally open for warm weather?

IX.  Shelter-in-place locations and characteristics

  • If SIP will occur in the path of shifting winds, how long will exposure last?
  • If exposure is lengthy, how will residents be advised when or if to move?
  • Older buildings will allow greater exposure rates.
  • Is the building tall? Plumes will rise and collect on upper floors.[9]
  • Are valuable pets or livestock present?
  • Are animals permitted where people shelter?
  • Was the toxin release indoors?[10]

X.  Presence of Symptomatic People or Animals

  • What guidelines should be followed by affected people or their co-workers and family?
  • In the absence of medical experts, what should be done?

XI.  Medical Surveillance and Oversight

  • Are medical professionals involved in the recommendation to SIP?
  • Are medical professionals involved in the All Clear decision?

XII.  Toxin concentration and health effects

  • Which is more dangerous, the duration of exposure or the concentration of toxin?
  • How was the toxin released and how long is it expected to linger?
  • Does the toxin have a “shelf-life”?

Often forgotten is the question “At what point is it more dangerous to remain sheltering in place?” Argonne National Laboratory (ANL) has studied this issue[11] and suggested steps toward building a decision-tree or matrix for instituting and terminating SIP under very controlled circumstances at or near Army chemical stockpile sites. This document contains a useful bibliography. It concluded that there are no “off-the-shelf” methods available to institute, manage, or terminate SIP.

Based on multiple studies and methodologies, a general timeframe for particle infiltration was sought for unpressurized structures, leading to a determination of when the shelter would become more contaminated than the outside air. Options for dealing with this included ventilating the shelter while occupied or exiting the shelter and relocating. The ANL study concluded that further development was needed. As part of that development, they have designed Sync Matrix planning software.[12] Homeland Security also has begun using the Sync Matrix Planning Process to study the “disaster dimensions of time, space, and hazard characteristics.”[13]

Other study groups have asked similar questions, including queries about how to handle populations emerging from an SIP episode.

Others have approached single issues through a Decision Matrix. An example is the Agency for Healthcare Research and Quality study of Call Centers for Crisis Support, performed as part of the U.S. Dept. of Health and Human Services.[14] An example of a simple ranked Decision Matrix is described by the Hancock County [Maine] Hazard Mitigation Plan.[15]

Continuity Compliance continues to monitor these complex response issues and to support the development of a Decision Matrix to aid clients in designing their own specifically tailored education and response plans.

For more information on this subject, other business continuity topics or business continuity policies please write to:

Written by Don

[1] Sheltering_In_Place_As_A_Public_Action.doc.

[2] Actions_To_Take_When_Ending_Shelter_In_Place.doc

[3] Shelter_In_Place_It_Works_With_You.doc

[4] Shelter_In-Place_In_The_Work_Environment.doc or Shelter_In_Place.doc

[5] Issues_Related_to_Expedient_Shelter_In_Place.doc; see also EXPED.doc and Expedient_Respiratory_And_Physical_Protection.doc

[6] Residential_Shelter_In_Place.doc

[7] NICs_SIP_brief-examples.doc

[8] Family.doc

[9] Protecting_Building_Hazardous.doc

[10] Protecting_Buildings_From_A_Biological_Or_Chemical_Attack.doc

[11] Temporary_Shelter_In_Place.doc





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