- CDC extensively examines exposure prevention measures such as chemical agent monitoring systems and associated quality assurance, personnel protective equipment selection and use, special air handling provisions, and chemical agent control/capture techniques.
- CDC examines actual and theoretical chemical agent exposure events for human health risk significance. This could involve chemical agent release air dispersion modeling, and or reviewing worker exposure information, such as cholinesterase depression data or actual symptoms.
- CDC develops air exposure criteria with a margin of safety designed to protect workers and the nearby community.
- CDC provides a health-based resource to support state and local health professionals on chemical agent-related issues.
- CDC is available to help assess facility and community readiness for possible chemical agent release events.
- Chemical Materials Agency. About CMA, 2008.
- National Research Council. Assessment of the Continuing Operability of Chemical Agent Disposal Facilities and Equipment, 2007.
- National Research Council. Evaluation of Alternative Technologies for Disposal of Liquid Wastes from the Explosive Destruction System, 2001.
- It effectively breaks down any type of chemical agent to relatively harmless or controllable end products.
- The technology has matured into a reasonably well-controlled and well-understood body of knowledge.
- The technology provides capable operation in a manner that is safe to workers and the public.
- Weapon-related materials are put into containers that are closely examined for leaks before they are used.
- All containers are inspected and monitored again after they have been moved and off-loaded to the disposal plant.
- Air in the disposal facility passes through a cascading airflow system from cleanto increasingly contaminated areas to prevent migration of chemical agents to the outdoor environment.
- In specific areas of the plant where a chemical release is most likely, the air is continuously monitored with systems capable of detecting chemical agent concentration levels below those categorized as "acceptable" for occupational exposure.
- All gases released from disposal stacks are continuously monitored and the entire disposal system is programmed to stop if a chemical agent is detected.
- Airborne chemical vapors are contained within the disposal facility by a strong airflow system that pulls air in toward the main operations area and special exhaust outlets.
- The exhaust airflow is so strong that air can only move in one direction-back into the facility. This keeps contaminated air from escaping to the outside.
- The air captured by the exhaust system goes through a series of special carbon filters that effectively removes the chemical agent.
- Throughout the process, the air is monitored by sensitive equipment on back up power supplies to ensure that chemical agents are not escaping into the worker or community environment.
- Reviewing plans for the engineering controls and ventilation systems before the facility's construction to ensure that proper safeguards are included.
- Evaluating the systems before any chemical agent is introduced into the facility.
- Reviewing monitoring systems throughout the plant and in the exhaust to ensure they are working properly and are accurate.
- Conducting site visits and ongoing evaluations of the systems.
- Specially designed equipment monitors the air and gives a reading within a few minutes of the sample collection. This technology provides for near-real-time monitoring.
- Other types of monitors collect samples of air over a longer period of time to evaluate whether very low levels of chemical agents are present.
- Monitors and air-sampling systems are placed strategically throughout the disposal facility, within the exhaust system, and around the perimeter of the facility.
- If a chemical agent is detected, even at levels well below what may be harmful to people, corrective actions are taken.
- Reviewing DoD monitoring plans before they are implemented.
- Checking agent-monitoring locations to ensure that a sufficient number of monitors are in use and that they are placed in the proper locations.
- Analyzing data from each monitor to ensure that the system's readings are reliable.
- Conducting periodic process safety and industrial hygiene surveys.
What is CDC's oversight role in reviewing the Army's chemical agent disposal program?
CDC's oversight role in the program complies with the public law that requires CDC to review plans and other information particulars associated with transportation and disposal of lethal chemical warfare materials to ensure that public health and safety are adequately protected. This law specifies that these plans must include a description of the methods and facilities to be used, the destruction schedule, and the management organization. CDC's role does not include oversight of the storage of chemical warfare agents.
What is the specific legislative mandate for CDC's oversight role in chemical weapons disposal?
The mandate for CDC's oversight role is Public Law 91-121 (November 19, 1969) as amended by Public Law 91-441 (October 7, 1970). This law states "The Secretary [of Defense] has brought the particulars of the proposed transportation, testing, and disposal to the attention of the Secretary of Health Education and Welfare, who may in turn direct the Surgeon General of the Public Health Service to review such particulars with respect to hazards to public health and safety…and to recommend what precautionary measures are necessary to protect the public health and safety." Public Law 99-145 (November 8, 1985) states that "The Secretary [of Defense] shall provide for maximum protection for the environment, the general public and personnel…. Facilities shall be constructed…[for] the destruction of lethal chemical weapons and munitions…. The Secretary shall develop a comprehensive plan... and consult with the Secretary of Health and Human Services…."
What oversight function does CDC provide that the National Research Council (NRC), Environmental Protection Agency (EPA), Occupational Safety and Health Association (OSHA), or other agencies cannot provide?
CDC focuses on human health for both the worker and the community, particularly related to potential exposure to chemical agents. For example,
Why is destruction of the U.S. stockpile of chemical weapons so important?
The U.S. chemical weapons stockpile is obsolete and unnecessary. These weapons were produced primarily during the Cold War; they are not only outdated but also deteriorated, making safe storage increasingly difficult.
The United States has a deadline to meet. In 1985, the U.S. Congress established the Chemical and Biological Defense Program within the Department of Defense (DoD) and charged the program with the task of safely destroying all existing stockpiles of lethal chemical agents and munitions. Then in 1997, the United States joined 140 nations in ratifying the Chemical Weapons Convention Treaty, thereby agreeing that the United States would destroy the existing stockpile of aging weapons-principally mustard and nerve agents-not later than April 29, 2012 (revised date).
It is a matter of public safety. The chemical weapons stockpile is vulnerable to earthquakes, airline crashes, and other natural or human-caused disasters. Communities that surround these stockpiles have joined forces with the U.S. Army, the Federal Emergency Management Agency (FEMA), CDC, EPA, and their state and local officials to support dispose of the stockpiles.
What methods are used to destroy old chemical weapons?
Two methods, incineration and nonincineration technologies, are used to destroy old chemical weapons.
Incineration is the controlled heated combustion of waste materials that reduces them to ash, water vapor, carbon dioxide, and other products of the combustion process. Some of the stockpile consists of actual munitions that may contain not only chemical agents but also propellants or explosives that may no longer be stable. When the contents of these types of weapons are drained, the empty casings may contain residual materials that can be treated effectively by incineration.
The Army is using a variety of nonincineration technologies to destruct certain portions of the stockpile of chemical agents and recovered chemical weapons. The U.S. Army used neutralization hydrolysis with sodium hydroxide, followed by off-site post-treatment of the waste product, to dispose of chemical agents stored in bulk containers at Newport, Indiana and Aberdeen, Maryland. The nerve agent VX is stockpiled in bulk ton containers (TCs) at Newport. The TCs are drained in a Chemical Agent Transfer System (CHATS), pumped into a reactor contained in a sealed and monitored area, and hydrolyzed (neutralized) with a 200° Fahrenheit sodium hydroxide and water solution. The empty TCs are washed and decontaminated by heat treatment similar to that used at the incineration sites for residual contamination. The Aberdeen facility successfully completed destruction of its mustard stockpile in March 2005. The lessons learned at Aberdeen have been incorporated at the Newport facility.
In late 2002, the Army selected chemical hydrolysis followed by secondary treatment as the technology of choice for the stockpiles in Pueblo, Colorado, and Blue Grass, Kentucky. A contract was subsequently awarded to design, construct, pilot test, operate, and close the Pueblo Chemical Agent Destruction Pilot Plant and the Blue Grass Chemical Agent Destruction Pilot Plant. The technology chosen to destroy chemical weapons stored in Pueblo was neutralization hydrolysis followed by biotreatment. The technology chosen to destroy chemical weapons stored in Blue Grass was neutralization hydrolysis followed by supercritical water oxidation.
Other technologies used to destroy recovered chemical warfare materiels include the transportable treatment systems developed by the Non-Stockpile Chemical Materiel Project (NSCMP). Transportable treatment systems include the Explosive Destruction System and Single Chemical Agent Identification System (CAIS) Access and Neutralization System. These mobile technologies allow treatment of chemical warfare materiel at different locations. NSCMP's has also developed and deployed munition assessment systems, which allow operators to determine the chemical and explosive content of a munition without opening it. These noninvasive assessment systems - included the Portable Isotopic Neutron Spectroscopy System, Digital Radiography and Computed Tomography System, Raman Spectrometer, and Mobile Munitions Assessment System - use x-rays, gamma rays, and lasers to identify and characterize the presence of any chemical agent in a munition, which allows for proper handling and treatment.
More information about chemical weapon destruction programs and technologies is available at the following Web sites:
Note: Because NAS/NRC catalogue links are updated as new reports are issued, a list of documents relevant to technologies and methods used to destroy chemical weapons is available at the home page (http://www.nap.edu). Access "Search all Titles" and enter the terms "chemical agent" or "chemical agent disposal."
Why is incineration the most common method of chemical agent destruction?
Incineration was selected in the early 1980s by DoD as the preferred method for disposal of chemical agents and munitions after long and careful consideration of several technologies. The NRC endorsed this selection in 1984 and continues to regard incineration as a demonstrated safe "baseline technology".
Incineration is appropriate for several major reasons:
How reliable is the incineration process?
No community resident has ever been exposed to harmful levels of chemicals from disposal operations. To date, millions of pounds of chemical agents have been destroyed safely at the Johnston Atoll facility in the Pacific Ocean; in Tooele, Utah; Anniston, Alabama; Umatilla, Oregon; and Pine Bluff, Arkansas.
A number of safeguards are built into the materials transport and disposal systems. For example,
For more information about incinerator air emissions and safety issues, read
What keeps harmful chemicals from escaping into the community environment while the weapons are being destroyed?
Engineering controls are the first line of defense in protecting the public when a chemical agent is being destroyed at one of the DoD's chemical weapons disposal facilities:
CDC staff help ensure that engineering controls remain effective by
To learn more about the carbon filtration system, read National Research Councils Carbon Filtration for Reducing Emissions from Chemical Agent Incineration, 1999
What is CDC's role in the offsite shipment of secondary waste and hydrolysate?
The Army has proposed and is pursuing a shift in its program to manage and dispose of secondary wastes from chemical agent disposal facilities. A key aspect of this proposal is to transition control and management of potential chemical agent-contaminated waste from the Army to off-site commercial hazardous waste-treatment facilities. CDC continues to monitor public health aspects of treating secondary waste by reviewing documentation provided by the Army and its contractors. The documents typically provided to CDC include information on characterization of the waste, specific plans for health and safety, and the risk associated with transportation.
CDC is aware of the scheduling and cost considerations of this new approach to managing secondary chemical agent wastes. However, CDC's position is that the approach used to assess risk for such a change must clearly demonstrate that human health and safety risks are fully considered and satisfactorily addressed.
More information about secondary chemical agent waste is available in the NRC's Review of Chemical Agent Secondary Waste Disposal and Regulatory Requirements, 2007.
How is the air within the disposal facility monitored?
Chemical agent monitoring is critical to ensure that the environment, facility personnel, and nearby residents are protected.
How does CDC help ensure that the Army's air-monitoring systems at the chemical weapons disposal sites are adequate to protect public health?
CDC's role is to assist in providing continual improvements or refinements in air-monitoring technology for the chemical agent disposal program. Improving chemical agent detection and sensitivity levels, avoiding interferents, and reducing sampling and analytical time for near-real-time instruments are important goals endorsed by CDC.
Although current monitoring systems are meeting the intended requirements, CDC regularly conducts oversight visits to examine air-monitoring systems. Recent reviews generated several recommendations for changes and improvements that will support operational schedules and that can be reasonably accomplished in a timely manner. These recommendations have been provided to the Army, and the Army is in the process of implementing them. CDC's recommendations will improve air-monitoring systems without causing unnecessary program delays and the increased public risk associated with longer storage from such delays.
In addition to the air monitoring systems, multiple safety features have been designed throughout the process along with automated backup systems for critical functions. If part of the disposal process is not operating correctly, the system detects the problem and automatically shuts down the entire operation safely.
CDC is involved in ensuring that chemical monitors are operating accurately. CDC staff are involved in the following activities:
How are employees of the disposal facility protected from exposures?
In addition to the facility's elaborate cascading airflow and filtration system, employees are provided protective apparel, depending on their level of risk for exposures. This includes special protective suits developed by the Army and known as Demilitarization Protective Ensembles (DPE). Other protective apparel follows the OSHA and U.S. Army recommendations. Although protective apparel is designed to protect personnel, the main protection is provided by engineering controls, air filtration, and chemical agent containment.
How is CDC involved in the Chemical Stockpile Emergency Preparedness Program (CSEPP)?
CDC has limited its participation in CSEPP to addressing issues and answering questions from state health departments on resolving technical issues or clarifying information related to our medical readiness guidelines previously published in the Federal Register.
What contributions has CDC provided to CSEPP?
During the early days of the CSEPP program, local communities asked CDC to provide medical training in the treatment of chemical casualties. This training was conducted from 1987 to 1990.
In the 1990s, CDC recognized a need for local medical readiness guidance in responding to a chemical release in the community. In 1995, CDC proposed minimum standards for medical resources before initiating chemical disposal operations. These minimum standards were published in the Federal Register in 1995.
CDC has evaluated the medical readiness capabilities of a community at the request of the state health department. Evaluations of the Tooele, Utah, and Umatilla, Oregon, facilities were conducted.
More information on community and individual protection from chemical agents is available at
Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA 30333, U.S.A
Tel: (404) 639-3311 • CDC Contact Center: 800-CDC-INFO • 888-232-6348 (TTY)
