cal technologies similarly will have sufficient markets and profit potential to justify developers' covering the costs of complying with oversight requirements. However, pesticides used on minor crops or for limited purposes have less market potential. Some of the most efficacious and least risky products and approaches in EBPM will be modest in scale of use. Examples include release of classical self-perpetuating biological-control organisms that may produce great public good, but have virtually no commercial viability in the private sector. There is a need for a mechanism such as the IR-4 Program to encourage public support for development of biological-control organisms and products.

HUMAN HEALTH RISKS

Humans will come into contact with biological-control organisms, biological-control products, and resistant plants during their production and application and through exposure to organisms or residues that persist on crops and in the environment. The acute and chronic toxicities associated with conventional chemical pesticides are not found with most biological-control organisms and products. However, there may be other adverse health effects associated with their use. These include allergenic and other immune reactions and development of hypersensitivity through multiple exposure.

Health considerations are particularly relevant to workers involved in research on and production of biological controls. Workers applying or releasing the biological-control organisms, biological-control products, or resistant plants will also be exposed; therefore, packaging and application methods must address human exposure. EPA does require that hypersensitivity incidents be reported and may impose restrictions such as protective clothing to address potential problems associated with applicator exposure. It may be that adverse effects of biological-control organisms on human health could be restricted to certain individuals. For example, sensitivity to arthropod proteins is experienced only by some people who work extensively in arthropod rearing. Such risks can be managed by screening personnel for allergenicity or hypersensitivity and by providing protection against excessive exposure. When large-scale production of a biological-control organism is undertaken, concern about human exposure to proteins or other reactive materials is further warranted because sustained exposure to these materials can lead to acquired sensitivity and associated adverse reactions.

Microbes can produce numerous toxic and noxious metabolites, and mycotoxin contamination of food and feed from certain microbial control organisms is a legitimate concern (Betz et al., 1990). Appropriate screening for toxic components should therefore be included in risk assessment. In many cases, however, metabolites produced by biological-control agents are highly specific to the target pest and pose a minimal threat to human health. For example, Bt toxins are quickly degraded within the mammalian gut, reducing the potential for their accumulation within the mammalian system. Infrequently, the proteins cause



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