When a client organization—say, the Non-Stockpile Chemical Materiel Project (NSCMP)—identifies the need for new analytical or operating procedures for its chemical operations, the Edgewood Chemical Biological Center (ECBC) is generally responsible for their development. At the U.S. Army Engineering Support Center, Huntsville (USAESCH) RCWM projects, ECBC is typically responsible for preparing the plan for air monitoring and analysis methodologies for chemical agents (and other hazardous chemicals, if required) in accordance with U.S. Army standards (U.S. Army, 2007c, 2008e) for setting up stations that monitor the air for chemical agents during all phases of the response action, supporting USACE to maintain any filter units for vapor containment and conducting on-site analysis for headspace samples collected from media suspected of being contaminated with chemical agent. The committee judges vapor containment facilities and filtering techniques to be adequate and thus does not discuss them in detail in this chapter.
The choice of monitoring equipment is based on the type of monitoring to be performed and the types of agent involved. Air monitoring equipment systems have been described in detail previously (NRC, 2005a). Monitoring systems and their associated operating procedures used at non-stockpile sites must be appropriately certified before use. The following monitoring equipment systems may be used for the detection of chemical agents present in the air at non-stockpile disposal sites, at stockpile disposal sites, and at storage facilities (U.S. Army, 2004c; NRC, 2005a):
• The Miniature Chemical Agent Monitoring System (MINICAMS) is an automatic air monitoring system that collects compounds on a solid sorbent trap (typically a porous polymer) and thermally desorbs them into a capillary gas-chromatography column for separation and detection. It is a lightweight, portable, near-real-time, low-level monitor with alarm capability, designed to respond to G-series nerve agents, VX nerve agent; mustard; nitrogen mustard; and lewisite. Alarm levels for MINICAMS used at non-stockpile sites are typically set at 0.70 of the appropriate airborne exposure limit (AEL)4 (NRC, 2005a). MINICAMS was used at Camp Sibert, Alabama, with mixed results.5 It is expected that a similar experience will be encountered during other remediation efforts.
— The MINICAMS was used in the location of an anomaly as that anomaly was being investigated and removed. As part of the MINICAMS calibration procedure, a midday challenge was used. This procedure can cause a delay in field operations of 2 to 3 hours if the initial calibration is unsuccessful.
— The MINICAMS is not sufficiently robust to be moved from anomaly to anomaly. This results in long downtimes. A more rugged, portable system for near-real-time air monitoring is needed.
— In a certain part of Camp Sibert called the “mustard soaking pit,” the presence of trichloroethylene (probably used as a decontamination fluid or as a component of decontamination fluid) interfered with determination of mustard by MINICAMS.
• Open-path systems such as fence-line Fourier transform infrared spectrometry air monitoring (OP-FTIR) send a beam of light through the open air, to a reflector and then back to a receiver. If gases that absorb light are present in the beam path, they can be identified and quantified. This technology will have limited applicability to nonstockpile cleanup operations because of its limited sensitivity. It is marginal for detection at the short-term exposure limit (STEL) level (NRC, 2005b).
• The depot area air monitoring system (DAAMS) is a portable air-sampling unit that is typically used for agent confirmation sampling (following a positive result using MINICAMS, for example). It is designed to draw a controlled volume of air through a glass tube filled with a solid sorbent collection material. After sampling for the predetermined period of time and flow rate, the tube is removed from the vacuum line and transferred to a suitable laboratory facility6 for gas chromatography analysis to determine the presence, type, and quantity of agent. This technique is sufficiently sensitive and will allow analysis down to the appropriate AEL for the relevant agent.
• A new air monitoring system, the multiagent meter, is being developed by Sandia Livermore under NSCMP sponsorship (Rahimian, 2010). This is a handheld device that can simultaneously analyze for mustard
4Airborne exposure limits (AELs) are levels of exposure to hazardous materials to which workers and the unprotected general population can be exposed without experiencing adverse health effects. AELs are established by the Centers for Disease Control and Prevention (CDC). They include the short-term exposure limit (STEL), the level at which an unprotected worker can operate safely for one or more 15-minute periods (depending on the agent) during an 8-hour workday; the worker population limit (WPL), the concentration at which an unprotected worker can operate safely 8 hours a day, 5 days a week, for a working lifetime, without adverse health effects; the general population limit (GPL), the concentration at which the unprotected general population can be exposed 24 hours a day, 7 days a week, without experiencing any adverse health effects; and the immediately dangerous to life or health (IDLH) limit, the level of exposure that an unprotected worker can tolerate for 30 minutes without experiencing escape-impairing or irreversible health effects.
5Karl E. Blankenship, FUDS Project Manager, Mobile District U.S. Army Corps of Engineers, “Remediation of Contaminated Soil at Camp Sibert, Alabama: The Installation Manager’s Perspective,” presentation to the committee on November 3, 2011.
6One example of a suitable analytical laboratory facility is the mobile analytical platform used by ECBC.