Introduction - Occupational Health and Workplace Monitoring at Chemical Agent Disposal Facilities - page 2

effects on reproductive function in doses that are not
maternally toxic. Moderate or higher exposures to GB
have been associated in some individuals with transient
difficulties in concentration, anxiety, and depression
for days or weeks after exposure. Occupational expo-
sures have been associated with subtle changes on
electroencephalograms of undefined significance. Ani-
mal studies suggest that cardiac toxicity may be associ-
ated with severe acute nerve-agent exposure, but no
conclusive evidence of these effects has been observed
in humans (Munro et al., 1994). Therefore, no adverse
acute or chronic effects are expected if exposure guide-
lines are followed.
Sulfur mustards (designated H [mustard], HD [dis-
tilled mustard], and HT [HD and T mixture]) do not
present acute lethal hazards. Their principal effect is
severe blistering of the skin and mucous membranes.
Epidemiological evidence indicates a causal relation-
ship between exposure to mustard agent at high con-
centrations and the development of chronic nonreversible
respiratory disorders, such as chronic bronchitis and
asthma, and ocular diseases, such as delayed recurrent
keratitis and prolonged, intractable conjunctivitis
(IOM, 1993). Sulfur mustard has been classified as a
known human carcinogen based on evidence of in-

creased mortality from respiratory tract cancer in
humans. The increase was greater in individuals with
long-term occupational exposure than in those with
sporadic exposure (IOM, 1993; NTP, 2000). Estimates
of cancers induced as a result of accidental exposures
to agent apply only to mustard agents.
Once chemical agents are fully dispersed, they do
not tend to persist in the environment because of their
high chemical reactivity, particularly with water (hy-
drolysis). However, in extremely dry desert climates,
they can persist for considerable periods of time (U.S.
Army, 1988). The major environmental degradation
products of nerve and mustard agents have recently
been assessed and their persistence and toxicity evalu-
ated. A potential hydrolysis product of VX (S-(2-
diisopropylaminoethyl) methylphosphonothioic acid
[EA-2192]) is a degradation product expected to dis-
play a high level of mammalian toxicity. Some mus-
tard partial hydrolysis products are also toxic (Munro
et al., 1999).
Chemical agents in the U.S. stockpile are stored in a
variety of containers and munitions, including bulk
(ton) containers, rockets, projectiles, mines, bombs,
cartridges, and spray tanks. Figure 1-1 summarizes the
stockpile configuration for the eight continental U.S.

FIGURE 1-1 Location and size (percentage of original stockpile) of eight continental U.S. storage sites.
Sources: NRC, 1997a; OTA, 1992.