SECTION 4: RISK ASSESSMENT
• Effects of chlorine on population determined through evaluation of chlorine gas concentration zones, which were determined using ALOHA plume modeling software (see References)
• First effects on humans at concentration = 10 ppm
• Minimum lethal dose = 430 ppm for 30 min
• Median lethal dose (short-term exposure) = 1,000 ppm
Table 4.141 outlines the expected losses based on the above parameters. Table 4.141 – Estimated Casualties from Chlorine Attack
Population Affected 59 persons 89 persons
Injury Description
Fatality
Eye pain & swelling, headache, restricted airflow – difficulty breathing, coughing, chest pain, lung inflammation and edema, bloody sputum, vomiting, skin irritation, possible chemical burns Eye pain & swelling, headache, throat irritation, rapid breathing, coughing, chest pain, lung inflammation and edema, bloody sputum, vomiting, skin irritation Eye pain & swelling, headache, throat irritation, rapid breathing, coughing, chest pain, skin irritation
205 persons
426 persons
Eye irritation, headache, throat irritation, coughing, skin irritation
521 persons 481 persons
Eye irritation, headache, coughing, skin irritation
Source: EMCAPS tool
Scenario #2 – IED: Truck Bomb
Scenario Overview: An Improvised Explosive Device (IED) utilizing an ammonium nitrate/fuel oil (ANFO) mixture is carried in a cargo truck to a populated area and detonated. The bomb size is assumed to be 1000 lbs ANFO and the average space between persons is 3 feet, equivalent to a moderately crowded pedestrian area as might be found in an average large city or outside a stadium. It is assumed that the explosion takes place in a relatively open area (e.g. stadium parking lot, park, etc). The following assumptions apply:
•
ANFO - TNT equivalence = 0.82
• Blast pressure damage impact taken from National Fire Protection Association (NFPA) 921 Guide for Fire and Explosion Investigations - 2001 Edition, Table 18.13.3.1[b]
• Quantity of Cs-137 in bomb = 2,700 Curies
• Buildings and other physical structures are not considered in these calculations
Table 4.142 outlines the expected losses based on the above parameters. Table 4.142 – Estimated Casualties from IED Attack Blast Injuries
Population Affected
Total Dead
275 persons 482 persons 2,367 persons 885 persons
Total Traumatic Injuries Total Urgent Care Injuries
Injuries not Requiring Hospitalization
Source: EMCAPS tool
Radiological Poisoning Injuries Need Aggressive Treatment
Population Affected
2
Wake County, NC Multi-Jurisdictional Hazard Mitigation Plan
WSP June 2024 Page 268
Made with FlippingBook interactive PDF creator