Workplace Chemical Monitoring - Occupational Health and Workplace Monitoring at Chemical Agent Disposal Facilities - page 12

Agent hydrolysis by aqueous caustic solution is also
used at baseline incineration system sites where decon-
tamination solution is used to clean contaminated tools,
equipment, and structural surfaces. At these sites, spent
decontamination solution is processed through the liq-
uid agent incinerator afterburner (secondary chamber)
to destroy any residual agent or toxic hydrolysis prod-
ucts. This option will not be available at Aberdeen or
Newport, where decontamination solution may be pro-
cessed in the primary hydrolysis treatment step. No
agent is expected to remain in decontamination solu-
tion after several days at room temperature. However,
any liquids or solids shipped to off-site disposal facili-
ties should be analyzed before shipment if there is any
possibility of agent contamination. This is also true of
the brine solution (primarily sodium chloride, fluoride,
sulfate, and phosphate salts) left after the scrubbing of
acid gases formed by combustion in incinerators.
Solids that are known to be or suspected of being
contaminated with agent include activated carbon used
in the air filtration system or gas masks, DPE suits,
concrete in the munitions demilitarization building
(MDB) or storage igloos, and agent-exposed soil,
equipment, and tools. The usual methods of analysis
include (1) holding the solid(s) in an enclosed space,
such as a drum, at 70

very low agent vapor pressure even if a substantial
loading of agent were present. If the temperature were
raised, this agent could be released, posing a danger to
anyone not properly prepared or equipped.
Agent in soil or concrete is not a problem during
ordinary operations because gas-phase monitoring of
agent suffices in areas where agent spills may occur.
However, it is a potential problem during cleanup and
closure operations when these materials must be certi-
fied as agent free.

MONITORING NONAGENT CHEMICALS IN AIR

Much of the public concern about incineration is
based on the perception that incinerators emit chlori-
nated dioxins and furans, heavy metals, and other toxic
substances into the atmosphere, potentially harming
both the workforce and the public. The normal practice
at the incineration-based disposal facilities has been to
monitor only agent and carbon monoxide, carbon diox-
ide, nitrogen oxides (NO x ), and oxygen in the stack gas
to determine that the incinerator is operating properly
and that combustion is nearly complete. Other nonagent
stack emissions are analyzed only during trial burns
required to obtain or modify operating permits. The
Stockpile Committee has extensively reviewed the trial
burn emissions data from both JACADS (NRC, 1994c)
and TOCDF (NRC, 1999a) and determined that emis-
sions of organic and metallic species are exceptionally
low when the incinerators and their pollution abate-
ment systems are operating as designed.
The committee has recommended that the Army
consider periodically monitoring emissions for species
other than agent during normal operations as a means
of reassuring disposal facility workers and the public
that they are not being exposed to unacceptable risk
(NRC, 1994b). This issue is likely to become more
important since the Environmental Protection Agency
(EPA) issued a draft document indicating that one po-
tential incinerator emission, the most potent form of
dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin), is consid-
ered to be significantly more toxic than was previously
thought (EPA, 2000). Regular analyses for heavy
metals (e.g., Hg, Pb, etc.) should also be considered.
The Army has agreed to design and assess a plan for
periodic monitoring of SOPCs in stack emissions at
TOCDF, but this plan has not yet been finalized or
implemented.
In addition to emissions from combustion processes,
other potential sources of airborne compounds from

F and analyzing the headspace
vapor or (2) taking wipe samples from a solid surface
and analyzing them by solvent extraction, followed by
gas chromatography (U.S. Army, 1997a). The Army
has also developed a scheme for classifying the degree
of cleanliness of solid materials based on this
headspace analysis method, designated 1X, 3X, and
5X. 1 Normally solids (e.g., shell casings) are not
shipped off site unless they are at the 5X level (U.S.
Army, 1997a). Although this level of decontamination
may be satisfactory for steel or polymer materials, it
may not be satisfactory for activated carbon, which has
a high adsorptive capacity and could therefore give a

°

1 The agent contamination levels 1X, 3X, and 5X are defined on
Page 1 of Department of Army Pamphlet 385-61, Chemical Agent
Safety, Chapter 5 ( http://www.usapa.army.mil ) (U.S. Army,
1997b). 1X indicates the item has been partially decontaminated.
3X indicates that it has been surface decontaminated by locally ap-
proved procedures and bagged or contained in an agent-tight con-
tainer whose headspace analysis shows concentrations of agent
higher than 0.0001 mg/m 3 for GB, 0.00001 mg/m 3 for VX, or 0.003
mg/m 3 for mustard. 5X indicates that an item has been completely
decontaminated and may be released for general use or sold to the
general public in accordance with all applicable federal, state, and
local regulations.