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Introduction
For more than 50 years, the United States has maintained a stockpile of chemical agents and munitions distributed among eight sites in the continental United States and on Johnston Island in the Pacific Ocean. The nation is currently engaged in a concerted effort to destroy the materials stored at these sites safely and efficiently. An estimated cumulative total of more than 8,600 operating and oversight personnel will be required to staff currently operating and future chemical agent disposal facilities, and the safety and health of these employees is a high priority. This report examines and evaluates workplace chemical monitoring and worker health monitoring practices at currently operating disposal facilities.
CHEMICAL AGENT AND MUNITIONS STOCKPILE
Two basic types of chemical agents comprise the stockpile: cholinesterase-inhibiting (nerve) agents and blister (mustard and Lewisite) agents. Both types are frequently, and erroneously, referred to as “gases” even though they are liquids at normal temperature and pressure. 1
Nerve agents include organic phosphorus compounds designated VX, GB (sarin), and GA (tabun). These chemicals present a significant toxic hazard because of their action on the nervous systems of humans and animals through inhibition of the acetylcholinesterase enzyme. VX is more acutely toxic than GB, but the latter represents a greater initial exposure hazard because of its higher volatility (about the same as water) and the greater likelihood of its being inhaled. Cancer has not been associated with exposure to nerve agents or chemically and toxicologically similar commercial organic phosphorus insecticides (U.S. Army, 1999a). In general, chronic health effects in humans have not been associated with either long-term, low-level exposures or short-term, high-level exposures to nerve agents (CDC, 1988).
Some concerns have been expressed about the induction of organophosphorous-induced delayed neuropathy (OPIDN) by the nerve agents, as well as other possible delayed or persistent effects, such as cardiac dysfunction, psychological effects, and electro-encephalographic abnormalities. In a comprehensive study of these effects, Munro et al. (1994) came to the following conclusions: (1) no exposures to nerve agents have resulted in OPIDN; (2) these agents are not likely to be carcinogenic; (3) these nerve agents are not teratogenic; and (4) they do not have deleterious
1 The stockpile (the subject of the Army's Chemical Stockpile Disposal Program) consists of (1) bulk containers of nerve and blister agents and (2) munitions, including rockets, mines, bombs, projectiles, and spray tanks, loaded with nerve or blister agents. Buried chemical warfare materiel, recovered chemical warfare materiel, binary weapons (in which two nonlethal components are mixed after firing to yield a lethal nerve agent), former production facilities, and miscellaneous chemical warfare materiel are not included in the stockpile. The disposition of these five classes of materials is the subject of a separate Non-Stockpile Chemical Materiel Program. Information on the Army's overall chemical material disposal programs is available online at < http:www-pmcd.apgea.army.mil/text/w_body.html >.
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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 exposures have been associated with subtle changes on electroencephalograms of undefined significance. Animal studies suggest that cardiac toxicity may be associated 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 guidelines are followed.
Sulfur mustards (designated H [mustard], HD [distilled 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 relationship between exposure to mustard agent at high concentrations 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 increased 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 (hydrolysis). 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 evaluated. A potential hydrolysis product of VX (S-(2-diisopropylaminoethyl) methylphosphonothioic acid [EA-2192]) is a degradation product expected to display a high level of mammalian toxicity. Some mustard 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.
~ enlarge ~
FIGURE 1-1 Location and size (percentage of original stockpile) of eight continental U.S. storage sites.
Sources: NRC, 1997a; OTA, 1992.
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sites by agent and munition or containment system prior to the start of agent destruction operations at the Tooele Chemical Agent Disposal Facility (TOCDF) (NRC, 1997a).
CALL FOR DISPOSAL
Chemical Stockpile Disposal Program
Because of the aging of stockpiled chemical weapons, the continuing costs of storage, and the potential for accidental release, the United States has strong incentives to dispose of these weapons. In 1985, Congress enacted Public Law 99-145 to initiate the process of eliminating the U.S. chemical weapons stockpile with an expedited program to dispose of M55 rockets. These munitions are especially worrisome because they contain agent, explosives, and propellants in an integrated configuration and because the stabilizer components of the propellants degrade with age—thus increasing the potential for autoignition. In 1992, Congress enacted Public Law 104-484, which directed the Army to dispose of the entire unitary 2 chemical agent and munitions stockpile by December 31, 2004. Congress also directed that the Chemical Stockpile Disposal Program (CSDP) be implemented in a manner that ensures maximum protection of workers, the public, and the environment. In 1997, the Chemical Weapons Convention (CWC) (see below) was ratified by Congress, setting a disposal deadline of April 29, 2007.
Chemical Weapons Convention
The CSDP has evolved in parallel with worldwide efforts to control chemical agent precursors and eliminate chemical agents and munitions. Over the course of several decades, a broad, complex agreement known as the CWC was negotiated. Since 1993, the CWC has been signed by 174 countries and ratified by more than 140. The convention went into effect on April 29, 1997, six months after 65 countries had ratified it. Since then, both the United States, which was actively involved in negotiating the CWC agreement, and Russia, the world's largest holder of chemical agents and munitions, have also ratified it.
The CWC prohibits the development, production, acquisition, stockpiling, retention, transfer, or use of chemical weapons. Article IV requires that signatories destroy chemical weapons and any special facilities for their manufacture within 10 years (by April 29, 2007). Destruction of chemical weapons is defined as “a process by which chemicals are converted in an essentially irreversible way to a form unsuitable for production of chemical weapons, and which, in an irreversible manner, renders munitions and other devices unusable as such” (Smithson, 1993). The method of destruction is determined by each country, but the manner of destruction must ensure public safety and protection of the environment.
DISPOSAL TECHNOLOGY
In the early 1980s, the Army investigated a number of strategies for the disposal of chemical weapons. Among these were chemical destruction (“neutralization”), ocean disposal (now banned by federal law), stockpile consolidation with subsequent destruction, and disassembly followed by incineration of the various components. The Army selected incineration as the preferred technology for stockpile disposal. The National Research Council (NRC) Committee on Demilitarizing Chemical Munitions and Agents was formed in August 1983 to review the status of the stockpile and to assess available disposal technologies. In that committee's final report in 1984, incineration was endorsed as an adequate technology for the safe disposal of chemical warfare agents and munitions (NRC, 1984).
Pursuant to the enactment of Public Law 99-145, the Army began to develop the components of a baseline incineration system at its research and development facility, the Chemical Agent Munitions Disposal System (CAMDS), located at Deseret Chemical Depot (DCD), formerly a part of Tooele Army Depot, Utah.
In 1987, the NRC Committee on the Review and Evaluation of the Army Chemical Stockpile Disposal Program (Stockpile Committee) was formed to advise the CSDP. Construction and systemization (operational testing) of the first fully integrated baseline incineration system, the Johnston Atoll Chemical Agent Disposal System (JACADS), was completed in June 1990
2 The term unitary refers to a single chemical loaded in munitions or stored as a lethal material. Binary munitions have two relatively safe chemicals loaded into separate compartments; the chemicals are mixed to form a lethal agent only after the munition is fired or released. The components of binary munitions are stockpiled separately, in separate states, and are not included in the present Chemical Stockpile Disposal Program. However, under the Chemical Weapons Convention of 1997, they are included in the munitions that will be destroyed.
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on Johnston Island, located in the Pacific Ocean approximately 825 miles southwest of Hawaii. The JACADS facility, which recently completed its disposal mission and will soon start closure procedures, has had a twofold mission:
-
to serve as a demonstration facility for the baseline incineration system
-
to destroy the chemical agents and munitions stored on Johnston Island (completed in November 2000)
The successful demonstration of the baseline system at JACADS led to a second-generation incineration system now operating at the TOCDF in Tooele, Utah, that incorporated improvements based on JACADS operating experience, advances in the baseline technology, and recommendations by the Stockpile Committee. The design of these incineration systems (JACADS and TOCDF) is also based on the idea that the performance and safety of disposal operations would be greatly enhanced if stockpile feed materials were separated into distinct streams of agent, energetic materials, metal parts, and dunnage (packing, and associated waste material) prior to incineration. A schematic drawing of the TOCDF system is shown in Figure 1-2(NRC, 1999a). Systemization at the TOCDF began in August 1993, and agent operations began on August 22, 1996. Prior to the start of agent operations, a quantitative risk assessment (QRA) and a health risk assessment (HRA) were conducted (U.S. Army, 1996a; Utah DSHW, 1996). 3
In the TOCDF system, feed materials are separated inside a building with areas capable of withstanding explosions. The pressure in these and other areas where agent may be present is controlled to be lower than the ambient atmospheric pressure to prevent leakage from the building to the outside atmosphere. Two methods are used to remove agents from munitions and containers via remote control. Most containers are simply mechanically punched and drained. Projectiles, however, are not punched; following separation from associated dunnage, they are moved to a munitions processing area where they are mechanically disassembled and drained, yielding three material streams: agent, energetics, and metal parts, each of which is processed in a different incinerator or electrically heated furnace. Although energetics and metal parts may be contaminated by residual agent, the vast majority of agent (95 percent or more) is usually recovered during the draining procedure. 4 A detailed description of the TOCDF system and an analysis of its first three years of operation can be found in the recent NRC report, Tooele Chemical Agent Disposal Facility: Update on National Research Council Recommendations (NRC, 1999a).
The same technology operating at TOCDF, with minor modifications, is now being implemented at three other storage sites (Anniston, Alabama; Umatilla, Oregon; and Pine Bluff, Arkansas). Both mustard and nerve agents are stored at these sites along with significant numbers of munitions filled with agent.
The stockpile (HD) at Aberdeen, Maryland, and the stockpile (VX) at Newport, Indiana, contain only the bulk chemical agents indicated in parentheses. At these facilities, the Army has decided to use chemical neutralization (hydrolysis) as the primary agent destruction method, followed by biological treatment at Aberdeen and supercritical water oxidation (SCWO) at Newport. A description of the process technology designs for these facilities, and the Stockpile Committee's evaluation of these designs, can be found in Integrated Design of Alternative Technologies for Bulk-Only Chemical Agent Disposal Facilities (NRC, 2000a).
Disposal technologies have not yet been selected for stockpile storage sites at Pueblo, Colorado, and Blue Grass, Kentucky. In addition to modified incineration technology, several alternative disposal technologies are being considered for implementation at these sites. The alternatives are discussed in two recent NRC reports (NRC, 1999b, 2000b).
CHEMICAL DEMILITARIZATION WORKFORCE
A substantial workforce is or will be involved in the operation of JACADS, CAMDS, and the eight continental U.S. chemical disposal facilities. The Army has estimated that total employment, counting both operating contractor and Army oversight personnel at the
3 The TOCDF QRA estimates the risk to the public and workers from accidental releases of chemical agent associated with all activities during storage at DCD and throughout the disposal process at the TOCDF. The HRA, which was conducted by the Utah Division of Solid and Hazardous Waste (Department of Environmental Quality), is a screening analysis to estimate possible off-site human health risks associated with exposure to airborne emissions from the TOCDF under normal and upset conditions. The HRA also estimates risks to wildlife and the environment.
4 At JACADS, recovery of HD from projectiles was difficult because of agent solidification, which necessitated modifications in disposal procedures.
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FIGURE 1-2 Schematic drawing of the TOCDF incineration system. Source: Adapted from NRC, 1994a, 1994b, 1994c, 1999a; U.S. Army, 1988.
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continental facilities, will total more than 8,600 over the life of the disposal program. The projected employment totals estimated by the Program Manager for Chemical Demilitarization for each facility are shown in Table 1-1 . However, based on operating experience at CAMDS, JACADS, and TOCDF, the total number of individuals will be smaller than indicated because some experienced operating and management personnel will move from established sites to newer ones as systemization begins. The relative distribution of contractor job categories will vary somewhat from site to site but will probably be similar to the distribution at TOCDF, which is currently about 40 percent operations personnel, 36 percent support service personnel, 12 percent office/clerical personnel, and 12 percent management/supervisory personnel.
Even allowing for employees who work at multiple disposal sites over the duration of the CSDP, Table 1-1 shows that a substantial number of people will be involved in the destruction of the stockpile. The focus of this report is on workplace chemical monitoring and worker activity and health monitoring practices at CAMDS, JACADS, TOCDF, and, by extension, at the other seven disposal facilities planned or under construction. The preparation, maintenance, and accessibility of records are also evaluated. Findings on current practices and recommendations for extending and/or improving them are then presented.
ROLE OF THE STOCKPILE COMMITTEE
Concurrent with the start of construction of JACADS in 1987, the Army requested that the NRC review and evaluate the CSDP and provide advice and counsel. The NRC established the standing Stockpile Committee for that purpose, beginning with a study of operational verification testing at JACADS, which was completed in March 1993. Several reports issued by the committee (e.g., Recommendations for the Disposal of Chemical Agents and Munitions [NRC, 1994a] and Review of Systemization of the Tooele Chemical Agent Disposal Facility [NRC, 1996]) concluded that the baseline incineration system was an adequate and safe method of disposing of the stockpile (see Appendix A for a complete list of Stockpile Committee reports).
Since its inception in 1987, the Stockpile Committee has exercised an advisory and oversight role for the Army's CSDP. Over the years, the Stockpile Committee has adjusted the composition of its membership to maintain a balance of disciplines necessary to meet the tasks at hand. Current members have expertise in analytical chemistry; biochemical engineering; chemical engineering; chemical industry management; chemical technology and manufacturing; civil engineering; combustion technology; engineering design and management; environmental engineering; environmental health policy; environmental restoration; facility clo-
|
Site |
Staff |
Duration of Operation (years) |
Estimated Turnover Rate (percent/year) |
Total Operating Employees |
Total Including Army Field Offices |
|
CAMDS |
275 |
25 |
10.0 |
963 |
963 |
|
JACADS |
504 |
10 |
23.4 a |
1,801 b |
1,847 |
|
TOCDF |
700 |
7.2 |
10.0 |
1,204 |
1,226 |
|
ANCDF |
571 |
3.8 |
10.0 |
788 |
807 |
|
UMCDF |
683 |
3.3 |
10.0 |
908 |
927 |
|
PBCDF |
547 |
3.3 |
10.0 |
728 |
744 |
|
PUCDF |
571 |
2.4 |
10.0 |
708 |
723 |
|
BGCDF |
571 |
1.8 |
10.0 |
674 |
688 |
|
ABCDF |
335 |
1.7 |
10.0 |
386 |
402 |
|
NECDF |
274 |
1.3 |
10.0 |
310 |
322 |
|
TOTAL |
8,470 |
8,649 |
|||
aEntry for JACADS is based on operating experience.
bIncludes additional adjustments based on operating history
Source: Adapted from U.S. Army 2000a, 2000b.Page 9
sure; hazardous waste management; health risk assessment; incineration; industrial hygiene; materials science; mechanical engineering; monitoring and instrumentation; occupational medicine; organic chemistry; physical chemistry; risk assessment, management, and communication; safety; toxicology; urban studies; and waste treatment and minimization.
STATEMENT OF TASK AND CONTENT OF REPORT
In June 1999, the Army requested that the Stockpile Committee examine issues related to workplace chemical monitoring and worker health monitoring at the currently operating chemical disposal facilities. The committee was also asked to evaluate the adequacy of current practices for disposal facilities in the planning or construction phases. The statement of task for this study is reproduced below.
Conduct a review of the chemical monitoring analytical methods and protocols being utilized for workplace monitoring at chemical agent disposal facilities within the Chemical Stockpile Disposal Program (CSDP).
Conduct a review of chemical agent disposal facility operations and records management for the ambient air monitoring for agent, and for exhaust stack and other waste stream emissions of agent and other substances of potential concern (SOPCs) that are characteristic of these facilities. Use Occupational Safety and Health Administration, and Environmental Protection Agency criteria for initial identification and evaluation of SOPCs.
Review medical monitoring and surveillance programs being used within the CSDP.
Review CSDP protocols for compilation and management of medical records of facility personnel.
Receive input, as appropriate, through documents and briefings from other organizations in the private and public sectors, about approaches and lessons learned from chemical monitoring of similarly complex facilities.
Develop findings and recommendations.
Chapter 2 focuses on (1) ambient air monitoring for the presence of chemical agents in and around chemical agent disposal facilities and (2) the monitoring of agent and agent breakdown products in liquid media and on solid surfaces. Current monitoring practices and their systematic deployment at disposal facilities are also discussed. Chapter 3 examines worker monitoring in the context of occupational and environmental medicine as practiced at operating chemical agent disposal facilities. The components necessary for a comprehensive occupational and environmental health program are presented, and current practices at the operating sites are compared with the recommended model. In Chapter 4 , current chemical monitoring, worker activity, industrial hygiene, and health record-keeping practices at operating disposal facilities are reviewed and evaluated. The continuity of records for workers employed at more than one site is examined. In Chapter 5, findings and recommendations based on the committee's evaluation are presented.
