99 ChemAware Chapter 04

7/31/2019 99 ChemAware Chapter 04

1/22

1999 Lockheed Martin Energy Research Corporation CA57

WHAT IS AN ACCIDENT


2/22

1999 Lockheed Martin Energy Research Corporation

OBJECTIVE

CA58

Identify types of potential chemical accidents and

associated hazards


3/22


Can be defined in several ways

an unplanned release of chemical warfare agent into

environment at levels which exceed those permitted by state

or federal regulations more conservative definition is any unplanned event that

could lead to the release of chemical warfare agent

AN ACCIDENT . . .


4/22 1999 Lockheed Martin Energy Research Corporation

Important to know amount of material accidentally

released

Amount of material released called source term

Source term and weather conditions at time of releasedetermine

how far downwind hazardous materials will travel

concentration of chemical warfare agent to which people

could be exposed

CA60

SIZE OF ACCIDENT


5/22 1999 Lockheed Martin Energy Research Corporation CA61

PROXIMITY TO POTENTIALACCIDENT SITE

Also important to know how close people might be to

a potential accident site and their location with respect

to airborne agent plume

Illustrated CSEPP installation and community



ACCIDENT LIKELIHOOD

Most likely accidents are small ones that do not pose a

threat except to someone in very close proximity to

accident

Large accidents (source terms large enough to pose athreat to community) have much lower probability of

occurring

Unlikely that an accident will cause injury or death to

anyone


7/22 1999 Lockheed Martin Energy Research Corporation

Engineers and scientists systematically studieddifferent ways accidents could occur and estimated

how likely events were that caused an accident

They estimated probabilities of many different

accidents and calculated number of fatalities that couldoccur for each accident

They calculated the consequences of each accident

Risk =Probability For

of X Consequences allAccident (Times) (Summed) Events

CA63

WHAT IS MEANT BY UNLIKELY?

Calculation of risk



POTENTIAL ACCIDENT TYPESAND HAZARDS

If accident large enough to pose threat to public,

dominant hazard is from breathing air in which agent

exists as vapor

Paths for liquid chemical warfare agent to travel from

accident to off-site are limited and relatively easy to

block therefore people off-site unlikely to encounter

liquid agent



THREE BASIC TYPES

OF POTENTIAL ACCIDENTS

1. Spill

2. Explosion

3. Fire



SPILL

(not to scale)

Onto ground or other surfaces

Resulting puddle of agent (liquid deposition) can

evaporate into vapor and drift downwind

Example of a plume resulting from a spill



(not to scale)

EXPLOSION

Causes droplets of agent to be formed

Larger, heavier droplets quickly fall to ground

(deposition)

Releases vapors and aerosols (smaller droplets andparticles) that can travel greater distances

Example of a plume resulting from an explosion


12/22


13/22


DIFFERENCE BETWEENAEROSOLS AND VAPORS

Think of a chemical agent release

in terms of hair spray coming from

a spray can:

when spray is release, it is an aerosol larger particles and/or droplets are

deposited near point of release

particles quickly fall out of air onto

hair and skinperson across room can smell hair

spray from breathing vapors released


14/22


It is very unlikely the public would be exposed to

droplets and aerosols

Particles will mostly fall out of plume (via deposition)

by time plume reaches installation boundary

WHAT IF AN ACCIDENT OCCURS?


15/22


16/22


ACCIDENT CATEGORIES

Selection of protective action strategies contingent on

characteristics of accident

Accident categories are group of accident scenarios

bound together by common source terms andmeteorological conditions

Designed to support grouping of large number of

protective action strategies

Each installation has set of accident categories

CA72


17/22


CHEMICAL EVENT EMERGENCYNOTIFICATION SYSTEM

Standard chemical accident notification

Provides a common language between installation and

off-site emergency responders Fosters clear understanding and ready reference for

emergency response actions

Off-site response consists of 4 levels

nonsurety (does not involve chemical warfare agents)

limited area, post-only, and community emergencies

(involve chemical warfare agents)

CA73


18/22


NON-SURETY EMERGENCY

General interest to public

Poses no chemical surety hazard

Action: Notification to IRZ designated points of

contact

CA74


Army Installation Boundary

Limited

Area

Boundary


19/22



Plume


Limited

Area

Boundary

LIMITED AREA EMERGENCY

Declared when predicted chemical agent no-effects

dosage does not extend beyond chemical limited area

Action: Notification of IRZ and State points-of-contact

IRZ emergency responseofficials may go to level

of readiness


20/22


POST-ONLY EMERGENCY

CA76


dosage extends beyond chemical limited boundary but

not installation boundary

Not expected to present danger to off-site public

Action: Notification of IRZ, PAZ,and State-designated

points-of-contact

IRZ response organizations

mobilize

precautionary protective

actions may be initiated

in nearby areas


Plume


Limited

Area

Boundary


21/22


COMMUNITY EMERGENCY


dosage extends beyond installation boundary

Action: Notification of IRZ, PAZ, and

State-designatedpoints-of-contact

all emergency response

organizations mobilize

IRZ and affected PAZ areasimplement specified

protective actions

CA77


Plume


Limited

Area

Boundary


22/22


Armys detection capability consists of low-level and

gross-level detectors

Any vapor detection efforts off-site would be

conducted by Army survey teams using appropriateequipment

CA78

CHEMICAL WARFAREAGENT DETECTION

Documents

99 ChemAware Chapter 04