Attachment II - Page 5 
evidence nor solid theoretical arguments have been advanced to support the 
position that recombinant ENA research poses any danger to human health or 
to the integrity of the natural environment. 
At this point, we doubt that the beneficial side effects of con- 
tinued regulation justify the expenditure of time and money required to 
maintain a regulatory apparatus that has been developed to protect society 
frcxn hazards that appear to be non-existent. 
(B) Reduction of Recxxtroended Containment Levels . In the absence of known 
or suspected hazards, it seems unjustified to single out certain classes of 
experiments as requiring elevated levels of physical containment. The cost, 
in discouraging variety and innovation and thereby limiting access to useful 
knowledge, is real, vAiereas the benefit is likely to be zero. The use of Pi 
containment, together with the highest available level of biological contain- 
ment appropriate to the experimental purpose, will keep the probability of 
escape and establishment very low without interfering with the conduct of most 
researdi. 
The prohibitions remain in force. Although we consider it unlikely 
that experiments in the prohibited categories will generate serious hazards, 
they represent the one area of the Guidelines which is addressed to risks 
whose nature can be specified, and that are in principle assessable. Restruc- 
turing of some of these categories aimed at delineating areas of real con- 
cern is desirable and is currently underway in the case of toxin genes. The 
results of such restructuring would be to define additional exceptions from 
the prohibitions, which would then appear in Part III of the Guidelines as 
amended by this measure. 
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