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Aligning Hazardous Materials with Varying Levels of Capability 39 that the likelihood of a hazmat release would fall in the high range. If the region has a large rail sorting yard as well, the likelihood might be increased to "very high." If CFSs show that a specific hazardous material was present as a single car on only a few trains, say less than 10 hazmat cars per day, then a "moderate" vulnerability level should be assigned. Similarly, if only a few cars per year of a specific type of hazardous material were shipped, the vulnerability could be set to "very low," less than 10-6 per year. Since the goal is to assign a risk metric and not a quantitatively assigned risk value to each scenario, a consistent assignment of vulnerability values is more impor- tant than calculating a quantitative value for each scenario. In some cases, empty cargo tanks or rail cars contain sufficient residue to require hazmat placards. Emergency response personnel might not be able to distinguish the residue nature of the shipment until after initiating response actions assuming a full container. Step 19 Record the appropriate vulnerability value for each scenario in your hazardous materials portfolio, based on the values in Table 20. Depending on the availability of information, it might be difficult to estimate the vulnerability term. You are not required to follow the formal process shown in Appendix B. If the formal process is not used, estimate the risk for the most likely release scenario. This would probably be a Class 3 flammable liquid release. Then use an order-of-magnitude scale to specify a lower vulnerability value for the less commonly shipped materials based on their shipment frequency. Appendix B contains more detailed examples regarding vulnerability calculations. Hazardous Materials Portfolio Example The following discussion uses a hypothetical jurisdiction and evaluates each of the terms in the risk equation to determine a risk metric for each scenario. Since the planning organization has been involved in developing the emergency response plan (ERP) for Facility Z, it is aware that the facility, which produces polyester resins, has several large vessels containing ethylene and receives over 20 rail tank cars of ethylene a week. Ethylene is highly flammable and will auto-decompose at temperatures as low as 150C. It has a lower flammability limit of 3 percent and an upper flammability limit of 100 percent. The decomposition is catalyzed by iron oxide on the tank surfaces. It is shipped in insulated rail tank cars (e.g., type 105J100W or other DOT-approved tank cars) having a maximum capacity of 25,000 gallons. These char- acteristics make BLEVEs or other explosions a possibility at the facility and on the rail line to the facility. Gasoline is shipped on the roads in the region, so the risk of fire following a road incident must be considered. The manufacturing process also uses small amounts of chlorine, which is also shipped in by rail. This could result in a toxic gas release from both the facility and the rail line. There is a major interstate through the jurisdiction and, from a CFS that the planning agency commissioned, shipments of anhydrous ammonia (considered a toxic gas) and 37 percent hydro- chloric acid are present. No identified shipments of radioactive material or etiologic/biologic agents were identified in the region. When addressing the hazards, you should consider large and small releases. Based on the above hazards, the hazard column in the risk profile can now be filled out as shown in Table 21. The risk metric in Table 21 would suggest that no training would be needed for incidents involving etiologic/biologic agents. That would be an incorrect conclusion because at all tier lev- els, awareness training is required. It might not be required for the area emergency response team to have all the equipment necessary to respond effectively to incidents involving these materials. Through awareness training, everyone would be able to recognize when these materials are pres- ent and also know whom to call for assistance if an accidental release of these materials occurred.

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40 A Guide for Assessing Community Emergency Response Needs and Capabilities for Hazardous Materials Releases Table 21. Completed risk portfolio. Consequence Hazard [H] Vulner- [C]* Capability Response Risk ability Facility or [ERC] Time [RTF] Metric Description Y/N [V] Pop. Env. Route Facilit y Z Fire (ethylene oxide) 1 4 3 2 1 1 12 Roads u, w, Fire (gasoline) 1 4 3 1 4 1 48 x, y Facilit y Z Explosion (ethylene oxide) 1 2 5 2 1 1 10 Railroad s BLEVE (ethylene oxide) 1 3 2 2 4 1 24 Facilit y Z Toxic Gas (chlorine) (L) 1 3 5 1 1 5 75 Facilit y Z Toxic Gas (chlorine) (S) 1 4 5 2 1 1 20 Railroad s Toxic Gas (chlorine) (L) 1 3 5 1 3 5 225 Railroad s Toxic Gas (chlorine) (S) 1 3 3 3 1 1 9 Roads x, w Toxic Gas (ammonia) (L) 1 2 5 2 4 5 200 Roads x, w Toxic Gas (ammonia) (S) 1 3 3 1 4 1 36 Roads x, u Toxic Liquid (37% HCl) (L) 1 2 5 2 4 1 40 Roads x, u Toxic Liquid (37% HCl) (S) 1 2 3 1 4 1 24 Radioactivity 0 Etiologic/Biologic 0 *The maximum of the consequence values (population and environmental) are used in the risk metric calculation. (S) small release; (L) large release. The vulnerability values in Table 21 are based on the discussions in Chapter 7 and Appendix B. The consequence values are based on Chapter 5 and Appendix C. Note that in this hypothetical jurisdiction, environmental consequences never exceed human-health consequences for any scenario. Table 21 shows the ERC and RTF terms for each scenario for this hypothetical jurisdiction. It also shows the calculation of the risk metric using the risk equation. The risk metric shows that the dominant risk is from toxic gas releases. If emergency response capabilities were improved for these releases, the risk to the public could be significantly reduced. Step 20 Multiply the values for vulnerability, the maximum of the two consequence values, the capa- bility and response time factor to obtain the risk metric for each release sequence. The results are shown in Table 21. If the assessment tool is used, this step is calculated automatically.