health and safety plan solid waste management unit assessment

JP-4 (JET FUEL 4) 64-21
Volatilization of JP-4 hydrocarbons in soil is another potential
source of human exposure. Exposures may be more intensive when the
soil is contaminated directly from leaking underground storage tanks
and pipes, rather than from spills. In such cases, the more volatile
components do not have an opportunity to evaporate before penetrating
the soil. Once in the soil, the hydrocarbons evaporate, saturating the
air in the soil pores, and the vapors diffuse in all directions
including upward to the surface. The vapors may diffuse into the
basements of homes or other structures in the area, resulting in
inhalation exposures to the buildings' occupants.
64.2.4 Other Sources of Human Exposure
The volatile nature of JP-4 fuel suggests that inhalation exposures
to residents in the vicinity of air fields may occur during
large spills. Volatilization also occurs during routine fuel handling
operations and from fuel losses during the cooling of jet engines
(1811) t but these sources are expected to result in negligible
exposures to residents in the area. Workers in the immediate area
could receive much greater exposures, however.
Human exposure to JP-4 fuel may result from fuel-jettisoning by
aircraft. The effect of the evaporated fuel vapors is considered
negligible (1912), but several exposure pathways exist for the fraction
reaching the ground.
The composition and fraction of the jettisoned JP-4 fuel that
reaches the ground depends upon the altitude of its release and the
temperature at ground level. For example, at a ground temperature of
-20-C, over 20% of the JP-4 released below 400 meters may reach the
ground but at a ground temperature of 2O'C, less that 1% of the JP-4
fraction will reach the ground regardless of the altitude of release.
At altitudes above 3000 meters, release height has almost no effect on
the JP-4 fraction reaching the ground: however the surface area of fuel
distribution will be affected (1913).
Because the volume of fuel released in a jettison may range from a
few thousand to over 50,000 liters (1912), the amount reaching the
ground may lead to significant human exposure if released at a lov
altitude. Contamination of surface water, crops and pasture land may
result in human ingestion. However, significant human exposure is
expected to be rare since Air Force directives specify that, whenever
possible, release be made over unpopulated areas and at altitudes above
1500 meters (6000 meters in some aircrafts) (1912).
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