Guam Hazard Mitigation Plan - Western States Seismic Policy Council

SECTIONFIVERisk AssessmentThe portion of EFMUTS and the GBS that could be exposed to a release from these facilities isnot included in this discussion. A HAZMAT release into the air would not affect the physicalstructure or function of these buildings and facilities. The people occupying these buildings andfacilities would be affected, but the best available data do not include any information on thenumber of people (e.g., average number of people, maximum number of people) occupying thesebuildings and facilities. It is likely that some of these people have been considered because theylive in the exposed area. Therefore, it is impractical to accurately determine or estimate thenumber of people occupying all of the facilities. That being said, the total exposed EFMUTS andGBS and the value of these exposed buildings and facilities are shown in Tables 5-20 and 5-21and Tables F-11 and F-12.HAZMAT: NPDES-Water Permitted FacilitiesApproximately 12 percent of Guam’s population (21,278 people) is directly exposed toHAZMAT releases to surface water from NPDES-permitted facilities, as shown in Tables 5-20and 5-21. The area of exposure of people to HAZMAT releases into surface water from NPDESpermittedfacilities was determined to be a 1-mile radius around each facility (regardless of landor water area). In the 2008 Guam HMP, a similar finding of 10 percent of the population wasfound to be potentially exposed to this hazard.The quantification of exposed people assumes that releases of catastrophic proportions wouldoccur at all of these NPDES-permitted facilities, which is unlikely. The best available data do notinclude any characterizations of the substances that could be released other than their releasepathway (surface water). The magnitude and toxicity levels of a release are also unknown. Thequantified exposure of people reflects a worst-case scenario. Therefore, this exposure analysisinherently overemphasizes the hazard.Unlike the 2008 analysis, in which Tamuning had the greatest number of people at risk to aHAZMAT release from a NPDES-permitted facility, the village with the greatest number ofpeople at risk in this 2011 analysis is Santa Rita. For the detailed analysis by village is shown inTables F-13 and F-14. As such, 5.294 people from Santa Rita could be exposed (60.5 percent ofvillage population), and 3,662 people from Tamuning could be exposed (17.3 percent of thevillage population). Mangilao has the third largest number of people potentially exposed to thishazard, with 2,930 people exposed (19.0 percent of the village population).The portion of EFMUTS and the GBS that could be exposed to a release from these facilities isnot included in this discussion. A HAZMAT release into the water would not affect the physicalstructure or function of these buildings and facilities. The people occupying these buildings andfacilities would be affected, but the best available data do not include any information on thenumber of people (e.g., average number of people, maximum number of people) occupying thesebuildings and facilities. It is likely that some of these people have been considered because theylive in the exposed area. Therefore, it is impractical to accurately determine or estimate thenumber of people occupying all of the facilities. That being said, the total exposed EFMUTS andGBS and the value of these exposed buildings and facilities are shown in Tables 5-20 and 5-21and Tables F-13 and F-14.HAZMAT: Hardfill SitesA moderate percentage of Guam’s population (17.1 percent, or 30,939 people) is directly exposedto an atmospheric release of HAZMAT from all of Guam’s hardfill facilities. This percentage is5-66