Decontamination and Clearance of U.S. Army …

Decontamination and Clearance of U.S. Army Chemical Agent Disposal Facilities

Environmental Public Health Readiness Branch Division of Emergency and Environmental Health Services

National Center for Environmental Health Centers for Disease Control and Prevention

4770 Buford Highway NE (F-60) Atlanta, GA 30341

January 2017

Decontamination and Clearance of U.S. Army Chemical Agent Disposal Facilities

Contents

Executive Summary......................................................................................................................... 1 Introduction .................................................................................................................................... 2

CDC's Role in the Disposal of Chemical Weapons .................................................................... 5 CDF Closure Process........................................................................................................................ 5

Planning..................................................................................................................................... 6 Records Review and Risk Assessments............................................................................... 7 Plan Development............................................................................................................... 9

Decommissioning and Decontamination...................................................................................... 10 Decommissioning.................................................................................................................... 10 Decontamination .................................................................................................................... 11 Identification and Remediation of Occluded Spaces........................................................ 14 Verification of Occluded Space Remediation and Decontamination ............................... 15

Clearance ...................................................................................................................................... 16 Post Clearance .............................................................................................................................. 21 Conclusion..................................................................................................................................... 22 References .................................................................................................................................... 23 Appendix. Supplemental Information Regarding U.S. Army Decontamination Techniques during

Closure of Chemical Agent Disposal Facilities.................................................................... 25

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Decontamination and Clearance of U.S. Army Chemical Agent Disposal Facilities

Figures and Tables

Figures

Figure 1. Stored Chemical Agent Projectiles (photo provided by the U.S. Army Chemical Materials Activity) ........................................................................................................................... 2 Figure 2. Stored Bulk Containers of Chemical Agent (photo provided by the U.S. Army Chemical Materials Activity) ........................................................................................................................... 3 Figure 3. Locations and Status of Chemical Agent Disposal Facilities ............................................ 4 Figure 4. Overall Chemical Agent Disposal Facility Closure Process............................................... 6 Figure 5. Generic Chemical Agent Disposal Facility Site Map......................................................... 8 Figure 6. Generalized Decommissioning Process ......................................................................... 11 Figure 7. Decontamination Process at Chemical Agent Disposal Facilities .................................. 12 Figure 8. Example of Tenting an Item for Headspace Monitoring ............................................... 13 Figure 9. Example of Fan Placement for Air Circulation (left) and a Fan Placement Map (right) 19 Figure 10. Example of an Agent Sampling Location ..................................................................... 20 Figure 11. Example of Plastic Sheeting Used to Seal Opening (left) and Smoke Testing of a Sealed Opening (right) .................................................................................................................. 20

Tables

Table 1. Example of Plastic Sheeting Used to Seal Opening (left) and Smoke Testing of a Sealed Opening (right).............................................................................................................................. 17 Table 2. Eight-Hour Worker Population Limit Concentrations..................................................... 18 Table 3. General CDF Concrete Clearance Levels ......................................................................... 18

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Decontamination and Clearance of U.S. Army Chemical Agent Disposal Facilities

Executive Summary

This experience is valuable because the closure of the CDFs provided unique examples of largescale clean up due to chemical agent contamination. The major phases of the closure process were planning, decommissioning and decontamination, clearance, and post-clearance. During the planning phase, potentially contaminated areas were identified. After identification of these areas, risk assessments were developed along with plans and procedures for decommissioning, decontamination, and verification of decontamination. Decommissioning activities included de-energizing equipment and performing gross decontamination. After gross decontamination, equipment and items were removed that could not be decontaminated efficiently or effectively. Remediation of spaces where chemical agent could be trapped was critical to decontamination. Without identification and remediation of these spaces, residual agent contamination could remain despite the rigor of decontamination efforts. For clearance after complete decontamination of a facility, unventilated air monitoring testing was used to determine the presence of any residual low-level chemical agent vapor emissions. To conduct unventilated air monitoring testing of an area, the area was sealed and isolated from a facility's ventilation system. This testing was performed on a room by room or area basis rather than by testing an entire facility. For post-clearance once all of a facility's unventilated monitoring tests were completed, a formal decision process was used to determine whether the process was successful. Once deemed successful, engineering controls for agent hazards were no longer required and the facility ventilation system could be shut down. The buildings were opened to the atmosphere and prepared for demolition.

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Decontamination and Clearance of U.S. Army Chemical Agent Disposal Facilities

Introduction

The United States began stockpiling chemical weapons during World War I. Eventually, these weapons were stored at eight sites within the continental 48 states and at one location approximately 800 miles southwest of Hawaii and included approximately 31,497 tons of chemical warfare agents (U.S. Army Chemical Materials Agency 2007). These agents primarily included the vesicant sulfur mustard and nerve agents sarin and VX configured as projectiles, mortars, bombs, mines, and bulk containers (Figures 1 and 2).

Figure 1. Stored Chemical Agent Projectiles (photo provided by the U.S. Army Chemical Materials Activity)

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Decontamination and Clearance of U.S. Army Chemical Agent Disposal Facilities

Figure 2. Stored Bulk Containers of Chemical Agent (photo provided by the U.S. Army Chemical Materials Activity) As the stockpiles began to age and safe storage became more difficult, it became clear that these weapons would require destruction. While a program for disposal was being developed, the United States and other countries signed the Chemical Weapons Convention (Organisation for the Prohibition of Chemical Weapons no date). This treaty required signatories to destroy existing chemical warfare agent weapons stockpiles, refrain from manufacturing new chemical warfare agents, and work toward the peaceful use of chemistry. To destroy the stockpiled weapons, disposal facilities were built adjacent to the storage areas. The U.S. Department of Defense (DOD) has destroyed all of the stored chemical weapons at seven of the nine storage sites--over 28,360 tons of chemical agent equaling more than 90% of the stockpile (Figure 3).

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Decontamination and Clearance of U.S. Army Chemical Agent Disposal Facilities

Figure 3. Locations and Status of Chemical Agent Disposal Facilities With chemical agent destruction completed, these facilities needed to be decontaminated and closed in accordance with their permits and applicable regulations. This paper documents the methods used to decontaminate and verify successful decontamination in closing DOD chemical agent disposal facilities (CDFs). This experience is valuable because the closure of the CDFs provided unique examples of large-scale clean up due to chemical agent contamination. This paper addresses the following aspects of the decontamination and verification process:

? Type and extent of contamination. ? Evaluation of hazards (e.g. respiratory, dermal). ? Future use of facility. ? Decontamination methods. ? Verification screening. ? Final verification of decontamination.

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Decontamination and Clearance of U.S. Army Chemical Agent Disposal Facilities

CDC's Role in the Disposal of Chemical Weapons

Title 50, US Code, Section 1512 directs DOD to provide the U.S. Department of Health and Human Services (HHS) with details about DOD activities related to the testing, disposal, or transportation of lethal chemical warfare agents. HHS reviews details of the proposed activity for implications to public health and safety and recommends precautionary measures, if necessary, to DOD. HHS delegated this responsibility to the CDC National Center for Environmental Health. After considering the potential for impacts to public health and safety during closure activities, DOD and CDC agreed that CDC would continue its role through the decontamination of a facility and disposition of contaminated materials.

CDF Closure Process

The overall strategy for the closure process was to successively reduce risk while fulfilling the requirements of a CDF's environmental permit. During this process, hazards were assessed to determine safety and environmental risks to define appropriate methodologies and controls. Given the highly toxic nature of the chemical weapons and the complexity of the facilities used to dispose of these weapons, closure of CDFs was a multi-staged process. Figure 4 summarizes this process for the CDFs (Program Manager for Chemical Stockpile Elimination 2008, URS 2008).

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