equipment and process technologies that have not been previously implemented at full scale, these facilities are designated as pilot plants, i.e., the Pueblo Chemical Agent Destruction Pilot Plant (PCAPP) and the Blue Grass Chemical Agent Destruction Pilot Plant (BGCAPP). However, each facility will have the capacity to destroy the entire chemical weapons stockpile stored at its location. The designs for these facilities have undergone a number of revisions from their original design proposals in 2004, and some downsizing for both technical and budgetary reasons. However, the designs have now been fixed and construction of the two plants is well under way. The RD&D permitting process recognizes the need for flexibility, and negotiations with regulators are ongoing at both sites. Table 2-1 lists the process equipment and machinery at both sites and their potential for being contaminated by agent.
In this chapter, the committee provides background on the safety regulations, procedures, and terminology that are used at chemical destruction facilities. The agent process designs at PCAPP and BGCAPP are also briefly described, followed by a description of the heating, ventilation, and air conditioning (HVAC) systems (the largest source of potentially contaminated activated carbon) common to both plants.
The safety procedures and activities related to agent contamination at chemical demilitarization facilities are based on the airborne exposure limits (AELs) that were set by the Centers for Disease Control and Prevention (CDC) in 2003 and 2004 and adopted by the Army, as described in pamphlet DA PAM 385-61, Toxic Chemical Agent Safety Standards (U.S. Army, 2008). The draft document entitled Assembled Chemical Weapons Alternatives (USAE ACWA) Chemical Agent Monitoring Concept Plan, which describes in detail the standards, processes, and procedures for protecting personnel and the public at the two ACWA sites, is the primary reference for the discussion that follows (U.S. Army, 2011a). Types of AELs based on vapor concentrations and duration of inhalation exposure doses are defined and presented for the three relevant chemical agents in Table 2-2. Guidelines from Volume 3 of Acute Exposure Guideline Levels for Selected Airborne Chemicals that were developed as acute exposure guideline levels (AEGLs) for various chemical agents, specifically GB, VX, and mustard agent in this case, are also included in Table 2-2 (NRC, 2003). Both sets of exposure levels are used by the Army.
As briefly mentioned in Chapter 1, the contamination level of waste is often determined by sealing it in a bag or, for large equipment, a plastic “tent” enclosure at 70°F or warmer, for a time sufficient for agent vapor to equilibrate with the waste in the ambient air space. Headspace agent vapor concentrations are then determined by a near- real-time (NRT) agent monitor, such as a miniature continuous air monitoring system (MINICAMS). The Army defines NRT as a measurement cycle of between 5 and 15 minutes. This is a system that provides monitoring for airborne chemical warfare agent using an automated gas chromatograph. The vapor screening levels (VSLs) defined and presented in Table 2-2 typically determine whether the waste can be shipped off-site without further on-site treatment in accordance with site-specific RCRA permit requirements. To be reutilized, an item must meet release levels given in Table 2-3.