ods include the judgments of external scientific panels with specific technical expertise, and judgment of experienced regulatory personnel. A consensus of multiple external scientific experts is likely to be more rigorous than regulatory judgments because disagreements among external experts are likely to lead to more robust risk assessments.

As indicated above, this committee agrees with previous NRC committees (NRC, 1989, 2000c) that there are no new categories of risk associated with transgenic plants. The categories of risks from transgenic plants include those associated with the movement of the transgenes, impacts of the whole plant through escape, and through impacts on agricultural practices, non-target organism effects, and resistance evolution. For this reason, the process of producing new plant varieties should not enter into the assessment. However, the committee’s analysis indicates that specific traits introduced by either of the two approaches can pose unique risks. For example, within the general category of “risks to non-target organisms,” production of Bt toxins in corn pollen could pose a unique airborne toxin-exposure that was never found in conventional corn varieties. For purposes of decision support this committee agrees with previous NRC reports which conclude that risks must be assessed on a case-by-case basis with consideration for the organism, trait, and environment.

Typically there are a number of comparisons that are appropriate for assessing the risks of transgenic crops. For example, the environmental effects of a transgenic crop could be compared to chemically intensive farming practices and to farming practices developed to be more ecologically sustainable. Another obvious comparison is that of a crop variety with a transgenic trait to a similar variety (that is, a near isoline) lacking that trait. Therefore, the maintenance of such varieties is critical for appropriate testing.

The committee recognizes that in any attempt to mitigate environmental risk there is a need to be mindful of the fact that avoiding one risk can sometimes inadvertently cause another greater risk. For example, a regulation that discouraged research on pest-specific, plant-produced compounds could in some cases lead to continued use of environmentally disruptive synthetic pesticides.

ANALYSIS OF THE APHIS REGULATORY PROCESS

The major focus of the committee’s work was on analysis of the scope and adequacy of the APHIS environmental review process for transgenic crops. There were three phases to the analysis. First, the committee examined the general statutes and rules used by APHIS to regulate transgenic plants and the documents that APHIS has developed as guidance for applicants. Next, APHIS assessments of specific applications for testing



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