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Since that time various "risk assessment" experiments, as well as 
deliberate attempts to test the "hypothetical risks," have been under- 
taken. The most extensive of these were sponsored by the National 
Institute of Allergies and Infectious Disease (NIAID), utilizing 
scientists expert in molecular biology and infectious disease both in 
this country and overseas. Three areas of conjectural concern have been 
addressed in the NIAID program relative to E. col i K12 hosts. The 
Falmouth Workshop (5) dealt with the potential innate pathogenicity of 
the organism. The polyoma experiments at the NIH (6, 7, 8, 9) as well as 
those in the United Kingdom (10) and the deliberations of the Ascot 
Workshop (11) dealt with a "worst possible case" scenario of the organism 
containing pathogenic DNA (j_.e., oncogenic or cancer causing). Recently, 
the Pasadena Workshop considered two issues. 8oth concerned colonization 
of the gut with an organism producing a biologically active hormone. One 
issue was the magnitude of the inherent pharmacological effect of the 
hormone and the second issue dealt with sequelae which might result due 
to immunogenicity of the hormone. The overwhelming conclusion from these 
and other risk assessment data is the unquestionable safety of _E. col i 
K12 hosts utilizing non-conjugative plasmids with carefully and fully 
characterized DNA inserts. I feel these conclusions are applicable not 
only to research and pilot plant stage fermentation but also to commercial 
scale production. These results justify the concept of biological con- 
tainment as well as physical containment embodied in the original 
Guidelines of June 23, 1976. Current recognition of the decreasing risk 
of recombinant DNA research is further exemplified by the action of the 
Recombinant Advisory Committee (RAC) on September 6-7, 1979, recommending 
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