Review of Systemization of the Tooele Chemical Agent Disposal Facility (1996)

This report is in response to an Army request for a review and assessment of the systemization of the Tooele Chemical Agent Disposal Facility (TOCDF), located at Tooele Army Depot, Utah. The report emphasizes issues raised in earlier reports by the National Research Council (NRC) Committee on Review and Evaluation of the Army Chemical Stockpile Disposal Program (Stockpile Committee) in 1993 and 1994.

Start of agent operations at the TOCDF is now scheduled for the first quarter of 1996. Although the Army has the overall responsibility for the decision to start agent operations (subject to meeting all regulatory requirements), the Stockpile Committee was asked to provide this report as further input to that decision. Specifically, the Army requested that the Stockpile Committee assess, prior to the start of agent operations, the Army's implementation of the committee's recommended changes and improvements in the safety and operations of the TOCDF.

To complete this report prior to the start of agent operations, the Stockpile Committee found it necessary to cut off the search for data and information after September 30, 1995. As of that date, some activities by the Army and Army contractors were still incomplete. However, procedures are already in place to assure and verify completion of the necessary tasks. Consequently, this report is based on the committee's review of the status of the facility several months before the scheduled start of agent operations and on the committee's understanding of the requirements that will be imposed by the Army and regulatory authorities before agent operations are authorized by the Army.

Chapter 2 describes the improvements implemented in the TOCDF design and operations as of the date of this report. Chapters 3 and 4 present the Stockpile Committee's evaluation of the safety and environmental performance during the TOCDF systemization. Chapter 5 discusses public involvement and concerns with respect to the TOCDF, and chapter 6 addresses the new risk assessment studies for the TOCDF. Chapter 7 presents findings and recommendations.

Since 1969, the Army and various committees of the National Research Council have addressed problems associated with eliminating the nation's stockpile of lethal unitary chemical agents and munitions. In 1985, the Army established the Chemical Stockpile Disposal Program (CSDP). In 1987, the present Stockpile Committee was established by the NRC at the request of the Secretary of the Army. The NRC efforts have produced a series of reports evaluating many aspects of the CSDP. A brief history of this mutual effort can be found in appendix B.

There are two basic types of chemical agents in the unitary stockpile: nerve agents (GB, VX) and blister agents (mustard). The agents are contained in a variety of bulk containers and munitions. Munitions such as M55 rockets and various other projectiles have associated explosives and propellants (so-called "energetics"), which also require disposal. The amount and types of agents, energetic materials, and associated metal containers differ from site to site. The stockpile at the Tooele Army Depot includes all types of agent, munitions, and bulk containers.

Disposing of chemical agents and munitions means releasing all unitary stockpile materials from Army control after they have been altered to satisfy both international treaty requirements and domestic environmental requirements. Waste streams from disposal processes may be gaseous, liquid, or solid. A number of federal and state environmental regulations govern disposal operations in the continental United States, including the Resource Conservation and Recovery Act (RCRA), the Toxic Substances Control Act (TSCA), the

Clean Air Act, the Clean Water Act, and the Hazardous Materials Transportation Act.

The performance and safety of candidate disposal methods are greatly increased if stockpile feed materials are separated into distinct streams of agent, energetic materials, metal parts, and dunnage (packing and other miscellaneous material) prior to disposal or destruction. A schematic drawing of the baseline incineration system is shown in figure 1-1.

In the baseline system, these materials are separated inside a building that has areas capable of withstanding explosions. The pressure in these and other areas is kept below atmospheric pressure to prevent agents from leaking to the atmosphere. Agents are removed from munitions and containers by two methods. Most containers are simply mechanically punched open and drained, whereas artillery projectiles are mechanically disassembled and drained. These processes yield three material streams: agent, energetics, and metal parts. Energetics and metal parts may be contaminated by agents, although the vast majority (95 percent or more) of the agent is recovered separately. This material separation is a major safety feature of the baseline system, which allows for the design and operation of parallel disposal components that are properly matched to the three widely differing material streams.

Agents are pumped to and destroyed in a specially designed liquid incinerator (LIC). This incinerator consists of primary and secondary combustion chambers and a pollution abatement system (PAS). Agent flow is stopped if the combustion chamber temperature drops below 2,550°F. Associated energetics are burned in a rotary kiln deactivation furnace system; exhaust cases are sent to an afterburner and then treated by a pollution abatement system. Metal parts are decontaminated by heating them in a metal parts furnace (MPF) to 1,000°F for a minimum of 15 minutes. Any residual agent is vaporized from the metal parts and burned within the furnace. Exhaust gases are sent to an afterburner and then to a pollution abatement system that removes gaseous pollutants and particulates.

Agent compounds contain various inorganic atoms that result in significant acid gas products. Acidic gases are scrubbed from the discharge stream with alkali solutions to form salts. These wet salts, or "brine," are dried in a brine reduction area (BRA), and the resultant dry salts are stored for later disposal in hazardous waste landfills.

Contaminated and noncontaminated packing materials and miscellaneous waste, or "dunnage," are burned in a dunnage furnace (DUN). Because only trace amounts of agent may be present, dunnage furnace combustion produces low acid gas concentrations that do not require treatment prior to release. Exhaust gases are discharged through a separate stack without acid gas scrubbing.

Two auxiliary material streams are also processed: decontamination fluids are processed in the secondary combustion chamber of the liquid incinerator; and ventilation air is passed through banks of charcoal filters to remove any trace contaminants.

The baseline monitoring system is used to detect the release of agents and to monitor adherence to all environmental requirements. The system consists of a combination of the Automatic Continuous Air Monitoring System (ACAMS), which detects immediate threats (three to eight minute response time at 20 percent of permissible eight-hour exposure level for workers, see table B-4, appendix B), and the Depot Area Air Monitoring System (DAAMS), which has a slower response time but provides a much more sensitive measurement. ACAMS alarms require immediate agent-feed shutoff. DAAMS analyses are used to confirm ACAMS alarms and to document environmental compliance.

A comprehensive description of the baseline incineration system is provided in appendix B.

Additional information on the chemical agents in the U.S. stockpile as well as on associated munitions and containers is presented in appendix B, which outlines inventories at the Tooele Army Depot and presents an overview of the baseline incineration system as implemented and tested at Johnston Atoll Chemical Agent Disposal System (JACADS). Comprehensive data on the stockpile can also be found in a number of other reports (NRC, 1984; U.S. Army, 1988). The baseline system is described in more detail in several reports (MITRE, 1991, 1992, 1993a, 1993b, 1993c; NRC, 1994a).

Pertinent findings and recommendations from prior Stockpile Committee reports can be found in appendix C. To assist the reader, an alpha-numeric code has been assigned to each of these findings and recommendations and accompanies their use throughout this report.