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U.S. Department of Health and Human Services

Animal & Veterinary

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FDA Requests That Ball Clay Not Be Used In Animal Feeds

October 14, 1997

In a letter dated October 7, 1997, the Food and Drug Administration (FDA) asked producers or users of clay products in animal feeds to cease using ball clay in all animal feeds and feed ingredients. For the past several months, the FDA, the Environmental Protection Agency, and the Food Safety Inspection Service of the U.S. Department of Agriculture have been tracing the source of elevated levels of dioxins first found in chickens grown in the southern U.S. The source of the dioxin contamination was traced to a mined clay product called "ball clay," which is occasionally used as an anti-caking agent in soybean meal, in other feed components, and in complete animal feeds. FDA based its request to cease using ball clay in all feeds on these dioxin findings.

Ball clay, which is a term that originated from an early English mining practice of rolling the highly plastic clay into balls weighing 30 to 50 pounds, is not specifically listed as a Generally Recognized as Safe (GRAS) substance or as an approved food additive, but it has a history of use in animal feeds. It is listed in the Association of American Feed Control Officials, Inc. Official Publication as an acceptable anti-caking agent and pelleting aid not to exceed 2.5 percent in finished feeds.

Dioxins are found throughout the environment in very low levels, often originating as a waste by-product of chlorinated chemical manufacture, bleaching, and combustion. Due to the chemical properties and environmental persistence of dioxins, humans and animals accumulate dioxins over time. Continued exposure to elevated dioxin levels in animal feed increases the risk of adverse health effects in animals and to humans consuming animal-derived food products.

Since the dioxin levels in the ball clay were significantly elevated, FDA is recommending that the use of ball clay in animal feeds be discontinued. FDA intends to initiate the process to determine that ball clay for use in animal feeds is not GRAS, and that, in the absence of a food additive regulation, its use in animal feeds is prohibited.

Although the investigating agencies have no data showing that other mined clay products have similarly elevated levels of dioxins, this possibility cannot be dismissed. Until more is known about the source and pattern of distribution of these dioxins, mined clay products of all types should be used with caution in the production of animal feeds.

The food, feed, and mining industries have cooperated with the Federal agencies in this investigation. The Federal agencies appreciate their assistance during the investigation and look forward to their continued cooperation.

A copy of the letter sent to the producers and users of clay products in animal feeds will be available on the FDA/CVM Internet Home Page or by calling CVM's Division of Compliance on (301) 594-1785.


Contact FDA

240-276-9115 FAX
Issued by: FDA, Center for Veterinary Medicine

Communications Staff, HFV-12

7519 Standish Place

Rockville, MD 20855