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extends 22 km downwind from the tank. The reduced windspeed at
night causes the gas to disperse less resulting in a longer
plume. The plume in the nighttime scenario is a immediate threat
either to the port or the camp area depending on the wind
direction. The simulations assume typical daytime and nighttime
conditions. In addition, the plume will persist until the
chlorine is depleted.

6. If all 110 MT of chlorine are released instantaneously during
the day, the resulting lethal cloud would reach the camp area in
17 minutes and the port in 26 minutes. The diameter of the cloud
would be 1.7 km. If the explosion occurs at night, the resulting
cloud would have a diameter of 2.5 km and would reach the camp
area in 59 minutes or the port in 93 minutes.

7. In summary,  if the tanks are ruptured, the worst-case scenario
is at night. If the chlorine gas is released instantaneously, the
daytime scenario is worse because less time is required for the
lethal cloud to reach critical areas than the nighttime scenario.
If the size of the lethal cloud is a factor, the nighttime
scenario is worse.


     e. Oil Wellheads and Pipelines

           1) There are numerous oil wellheads and pipelines
throughout the region. If the wellheads or pipes exploded or
ruptured, the threat of a serious fire is significant. Equally
significant is the threat of hydrogen sulfide (H2S). H2S is a
colorless, flammable, and toxic gas. Primarily a respiratory
hazard, H2S in low concentrations can cause serious irritation to
the eyes and mucous membranes of the nose, mouth, and throat. In
higher concentrations, the gas has a distinct smell of rotten
eggs. More importantly, the ability t6 smell the gas decreases at
higher concentrations,  i.e., the sense of smell becomes
desensitized. Under these circumstances it becomes imperative to
don the protective masks at first evidence of the presence of
H2S.

           2) H2S does not penetrate the masks. The active
compounds found on the charcoal media used in the Ml7Al masks
will protect against penetration for the life of the filter. As
 is the case with all filters, extended wear of the mask in a
contaminated environment ultimately results in the need to change
the filters. There is insufficient information available to
 assess the lifetime of the Ml7Al filters under various
 conditions. Donning the protective mask when }{2S is first
 detected will preserve the individual's sense of smell so that
 the gas mask filters can be changed when needed. Appendix F
 provides additional information concerning the toxicity of Ii2S.

           3) The explosive nature of }{2S is an additional cause
 for concern. An explosion is particularly likely for locations in

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