During the Gulf War, Coalition forces faced an enemy known to have used chemical warfare agents in combat and suspected of having a biological warfare capability. Based on this biological threat, the US Central Command took actions to protect our forces and establish procedures to detect and report Iraq’s use of the biological warfare agents they were assessed as possessing. Although we have no documented reports of such use, some veterans have suggested exposure to biological agents may be related to their unexplained illnesses. In an effort to document what the Department of Defense knows about biological threats or use during the Gulf War, the Special Assistant initiated this investigation to explain the biological threat, identify the actions US forces took during the war to detect and report biological exposures, and assess the possibility Iraq used biological warfare agents during the war.

This investigation has found no evidence Iraq used biological warfare agents. Even more importantly, it appears continued investigation is unlikely to shed further light on this issue. With this report, the Office of the Special Assistant terminates its investigation, but does not dismiss the possibility new information about Iraq’s use of biological warfare agents against Coalition forces will surface. This report describes what the investigation found and why continued investigation is unlikely to yield new insights.


A. Methodology

Unlike our investigations of chemical warfare incidents, we had no specific reported event or incident to investigate for this report. Consequently, we spent much time researching records and tracking leads to accumulate information, anecdotal or otherwise, on biological warfare during the Gulf War. We conducted this investigation by:

B. Iraq’s Biological Threat

In 1990, the Defense Intelligence Agency (DIA) believed Iraq possessed two biological warfare agents, Bacillus anthracis and botulinum toxin, which cause the diseases anthrax and botulism, respectively.[1] In August 1990, the United Kingdom reported Iraq possessed a variety of delivery systems capable of delivering Bacillus anthracis and botulinum toxin.[2] Iraq also possessed the technical capability to produce and weaponize Yersinia pestis (see Tab G), the bacterium that causes plague.[3] Post-war information revealed Iraq had experimented with other biological agents as well (see Section II.C, Postwar Findings).  However, Bacillus anthracis and botulinum toxin were the primary threats during the Gulf War.

Bacillus anthracis, which exists world-wide[4] in nature (often in the soil), is a spore-forming organism, the spore being a hardy form that easily lends itself to use as a warfare agent. The spores causing anthrax are 1 to 1.5 micrometers[5] in size, oval-shaped, odorless, and tasteless. Inhaling between 8000 and 50,000 spores (a lethal amount, easily inhaled in one breath) can cause the disease’s onset.[6] Fifty thousand spores in a glass dish are invisible to the naked eye (in Figure 1’s scale, the white line at the bottom represents 10 micrometers in the image). To help comprehend how small the spores are, one common housefly can carry about 7.35 billion spores attached to its external body hairs.[7] Consequently, if 50,000 spores constitute a theoretically lethal dose, a housefly could carry a lethal dose for over 100,000 individuals.

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Figure 1. Scanning electron microscope image of Bacillus anthracis spores

If untreated until symptoms appear, inhalation anthrax (spores entering the respiratory system) is fatal in almost 100 percent[8] of those who inhale an infectious dose. Inhalation anthrax begins in the lymphatic system when the inhaled spores travel from the lungs to lymph nodes in the chest. At this point, a blood test will not reveal the disease. To spores, the lymph nodes are warm, dark, and rich in food. Here spores transform into reproducing bacilli and begin to kill tissues locally. As the bacilli multiply, they release toxins that cause septic shock and respiratory failure. The disease becomes detectable in the blood on about the third day. At this point, because of the extensive tissue damage and toxins released during reproduction, the immune system is overwhelmed and treatment will not reverse the course of the disease. Anthrax is not communicable. Breathing in mucous particles expelled by an infected person cannot spread anthrax because once the spores have transformed into reproducing bacilli in the lymph nodes, they no longer exist as spores in the lungs.[9]

The second of Iraq’s potential biological agents was botulinum toxin, of which there are seven types (A through G). They are among the most toxic substances known. Botulism is the clinical syndrome produced by one or more of these toxins. The estimated lethal dose is only 0.001 microgram per kilogram of body weight. Botulinum toxin kills by interfering with the nervous system, blocking neurotransmissions. Some chemical warfare agents, like the nerve agents sarin and VX, similarly attack the central nervous system, but botulinum toxin is much more toxic. In fact, "[b]otulinum toxin is 15,000 times more toxic than the nerve agent VX and 100,000 times more toxic than sarin."[10] The agent can be inhaled or ingested, causing a muscular weakness. The progressive muscular weakness is a precursor to sudden respiratory failure. The onset of the disease varies from hours to days after exposure, depending on the dose of the toxin. In untreated, exposed individuals, botulism has produced mortality as high as 60%.[11] Death has occurred in as few as 24 hours after symptoms develop. "Laboratory tests are generally of limited value in the diagnosis of botulism. … [A]erosolized toxin is usually not identifiable in serum or stool, whereas it is with foodborne botulism. … Toxin may be present on nasal mucous membranes and detectable by ELISA [enzyme linked immunosorbent assay] for 24 hours after inhalation."[12]

Iraq experimented with other biological agents, e.g. T-2 mycotoxin, aflatoxin, and Yersinia pestis (see Tabs E, F, and G, respectively). However, little was known of Iraq’s work with these other agents at the time of the Gulf War, and Coalition preparations and procedures focused on the agents causing anthrax and botulism (see Tabs C and D).

C. Postwar Findings

The Gulf War disrupted Saddam Hussein's biological, chemical, ballistic missile, and nuclear weapons programs. We have learned of Iraq’s weapons of mass destruction program principally through the efforts of the United Nations’ Special Commission (UNSCOM). After the war, the Security Council established UNSCOM to eliminate and verify the destruction of Iraq's biological, chemical, and ballistic missile programs. UNSCOM conducted a series of inspections to locate, examine, and destroy biological weapons and production facilities.[13]

Little or no information was available to UNSCOM on the size and scope of Iraq’s biological warfare program until August of 1995, when Saddam Hussein’s son-in-law Lieutenant General Husayn Kamil defected to Jordan. This prompted Iraq to admit to UNSCOM it had produced 8,500 liters of concentrated Bacillus anthracis, 19,400 liters of concentrated botulinum toxin, and 2,200 liters of aflatoxin. Iraq also admitted preparing biological warfare agent-filled munitions during the Gulf War, including 25 Scud missile warheads (5 anthrax, 16 botulinum toxin, and 4 aflatoxin), aerial bombs (157), and aerial dispensers, although Iraq did not use them.[14] Table 1 summarizes what we believed before the war about Iraq's biological warfare program, and what we learned after the war.

Table 1. Summary of Iraq’s BW program

Agent Status Pre-War BW Agent Assessment[15] Post-War BW Program Findings[16]
Weaponized and filled Bacillus anthracis
       (causes anthrax)
Botulinum toxin
Bacillus anthracis (causes anthrax)
Botulinum toxin
Aflatoxin (see Tab F)
Research and development Yersinia pestis
(causes plague)
Yersinia pestis (causes plague)
Clostridium perfringens (causes gas gangrene)
Trichothecene mycotoxin (T-2, see Tab E)
Vibrio cholerae (causes cholera)
Brucella species (causes brucellosis)
Staphyloccal enterotoxins
Wheat cover smut
Haemorrhagic conjunctivitis virus
Camel pox virus

D. US Biological Warfare Defense

Defense against biological and chemical warfare agents entails using common protective equipment and procedures. Unlike most chemical warfare agents, humans cannot absorb most biological warfare agents through unbroken skin (except for T-2 mycotoxin), so inhalation is the primary threat. The M17 standard individual protective mask used during the Gulf War would have provided adequate protection against all respirable biological warfare agents,[17] those that can be introduced into the body by breathing, between 1 and 5 micrometers in size. Larger particles probably will not migrate to the lungs, and breathing usually will expel smaller particles from the lungs.[18] For agents that can be absorbed through broken or intact skin, the standard individual protective mask coupled with the standard protective over-garments provide the necessary battlefield protection against any known biological warfare agents, if one has sufficient warning to don the garments.[19]

E. Gulf War Biological Warfare Medical Preparedness

On August 30, 1990, after the Armed Forces Medical Intelligence Center assessed Iraq had the capability to employ Bacillus anthracis and botulinum toxin as weapons, the Armed Forces Epidemiological Board recommended pre-exposure vaccination against anthrax and botulism to protect against possible exposure. The Assistant Secretary of Defense for Health Affairs and the three service surgeons general endorsed this recommendation to the Chairman of the Joint Chiefs of Staff. On September 27, 1990, the Commander-in-Chief, US Central Command was briefed on the threat and the recommendation. On December 31, 1990, a US Central Command working group endorsed a theater-wide vaccination program. The Commander-in-Chief, US Central Command made the final decision to initiate a vaccination program.[20] In retrospect, it is important to note that the anthrax and botulism vaccination program protected some servicemembers against Iraq’s anthrax and botulinum toxin weapons. A forthcoming information paper to be published by the Special Assistant will more thoroughly discuss the Department of Defense immunization program.

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