TAB F – Aflatoxin

The aflatoxins are a group of structurally related toxic compounds produced by certain strains of fungi.[127] Aflatoxins occur naturally in food crops such as peanuts, pistachios, almonds, walnuts, pecans, Brazil nuts, corn, cottonseed, and millet. Various studies and textbooks provide a wide range of opinions on aflatoxin’s effects on test animals and humans. The Textbook of Military Medicine does not discuss aflatoxin among the biological warfare agents.[128]

Before the Gulf War, intelligence agencies did not assess aflatoxin as a biological warfare agent Iraq would or could use.[129] In 1994, the Defense Intelligence Agency assessed Iraq had the capability to deliver biological warfare agents by bombs and Scud warheads but did not list aflatoxin as an agent.[130] In 1995, UNSCOM determined Iraq had produced, filled, and deployed various munitions with botulinum toxin, anthrax spores, and aflatoxin.[131]

There are several aflatoxin strains, with B1 the most common and most toxic. The US Food and Drug Administration says aflatoxins produce acute necrosis (cell or organ death), cirrhosis (a progressive liver disease resulting in liver failure), and cancer in several (not all) animal species. Chronic (three or more months) and acute (brief exposure of high intensity) exposure in animal tests produced a wide range of responses, depending on the subject’s age, health, and nutritional condition, as well as the length of exposure and dosage. Since all animal species studied are vulnerable to the acute toxic effects, the Food and Drug Administration says it is logical to assume aflatoxins may similarly affect humans.[132]

The London Hospital’s study on the effects of aflatoxin-contaminated feed established a dose/effect relationship between aflatoxin and liver cancer in rats. Feeding contaminated nut meal to rats produced liver cancer. For example, with pure aflatoxin B1, all the rats developed cancer by week 88 at a dose of 100 micrograms per kilogram of body weight. However, cancer failed to develop almost completely when using adult mice and hamsters as subjects.[133] In rats, aflatoxin B1 is the deadliest cancer-causing compound. However, adult mice are essentially totally resistant to aflatoxin’s cancer-causing properties because of how different species’ livers process aflatoxin. Casarett and Doull’s Toxicology, a standard textbook, states though aflatoxins have been studied and cause liver cancer in laboratory rats, the link to human liver cancer has not been proved. The wide range of susceptibility to aflatoxin B1 makes extrapolating animal data to humans difficult.[134]

Writing in the Journal of the American Medical Association, a former United Nations Special Commission on Iraq investigator stated:

It is difficult to understand why the Iraqis developed aflatoxin for weapons use. Although well known to medical science as a powerful nephrotoxin [kidney-specific toxin] and hepatotoxin [liver-specific toxin], aflatoxin has no known property useful for biological warfare. Possible explanations for Iraq’s interest in aflatoxin include [since it] is easier to manufacture than most other toxins, the Iraqi biological warfare program’s staff might have chosen to produce it to meet production goals set by higher authorities rather than its perceived biological warfare value. Whatever the case, Iraq’s aflatoxin-based weapons had little military utility.[135]

The classic example of the perceived short-term and long-term negligible effect on humans is this chronology of a suicide attempt using aflatoxin the Food and Drug Administration described as follows:

[A] laboratory worker ingested 12 m g/kg body weight of aflatoxin B1 per day over a 2-day period and 6 months later, 11 m g/kg body weight per day over a 14 day period. Except for transient rash, nausea, and headache, there were no ill effects; hence, these levels may serve as possible no-effect levels for aflatoxin B1 in humans. In a 14-year follow-up, a physical examination and blood chemistry, including tests for liver function, were normal.[136]

Wannemacher and others estimate the lethal aflatoxin B1 dose for 50% of the exposed population is one to four milligrams per kilogram of human body weight.[137] In practical terms, a 175-pound person would have to breathe in or eat an acute dose of between 80 to 318 milligrams of pure aflatoxin B1 to cause death. Compared with botulinum toxin, this dose is approximately one million times larger. Such a dose would be very difficult if not impossible to introduce into a human through inhaling a dry or wet aerosol.

In addition to aflatoxin’s extremely low toxicity, it would be hard to deliver at lethal dose rates on the battlefield. It is well understood the smaller the required lethal dose, the easier to transport and disseminate a biological warfare agent. The table below depicts the comparative amounts of biological and chemical warfare agents required to achieve the same effect on the battlefield.

Table 2. Quantity of biological or chemical agent required for effective open-air exposure of a 100-square-kilometer area under ideal meteorological conditions

Type Agent (Diseases) Quantity Required
BW Francisella tularensis (Tularemia) 0.2 kilograms
BW Bacillus anthracis (Anthrax) 0.2 kilograms
BW Botulinum toxin 8.0 kilograms
BW Ricin 8,000 kilograms (8 metric tons)



8,000,000 kilograms (8,000 metric tons)*



100,000 kilograms (100 metric tons)

* Aflatoxin data added to original sources for updated comparison

This information is adapted from a DIA document based on a study conducted during the 1960s. The Textbook of Military Medicine also contains the same data.[138,139] We extrapolated the amount of aflatoxin shown from published lethality data and added it to the original table to point out aflatoxin’s unsuitability as a biological warfare agent from a purely logistical transport and operational dissemination perspective. Delivering 8000 metric tons of agent—whose volume would equal approximately 211 10,000-gallon tanker trucks—would be difficult; moreover, the delivery aircraft would be vulnerable to air defense missile systems and defensive counter-air fighter aircraft during the process.

Nevertheless, Iraq admitted producing the 2,200 liters of aflatoxin and filling four Scud warheads with it during the Gulf War, although Iraq did not use them.[140]

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