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B. Impact of Experiments Conducted Under the Guidelines 
1 . Possible Undesirable Impacts 
It is apparent in reading several of the comments on the Draft EIS 
that the description of a theoretical approach to evaluating the probabil- 
ity of occurrence of a hazard from a given recombinant DNA experiment 
was confusing. That Section has been rewritten in the interest of clarity. 
As pointed out, it is not necessary to know the probabilities of all the 
individual events leading to a hazardous situation in order to obtain 
a useful estimate of the probability of its occurrence. 
Commentators noted the reference in the Draft EIS to NIH research 
designed to improve our ability to determine the risk probabilities of 
recombinant DNA work [20, 30]. The revised EIS identifies this 
research as that to be undertaken at the Frederick Cancer Research 
Center. In addition, NIH has initiated a contract-supported program 
aimed at significantly reducing presumed biohazards of recombinant 
DNA research through the development of safer hosts and vectors. 
The revised EIS also contains a new appendix, H, on the procedure and 
rationale for certification of EK2 host-vector systems. 
Two commentators faulted the Draft EIS for not covering long- 
range evolutionary consequences in this section [2,30]. Totally new 
material has been added to address the issue. 
In addition, quotations were introduced from recent public articles 
representing scientists' views on the issue of potential hazard. 
2 . Beneficial Impacts of Recombinant DNA Research 
This section of the EIS has been updated. 
CONCLUSION 
Many of the issues raised by the commentators on the Draft Environ - 
mental Impact Statement were previously considered in the development 
of the NIH Guidelines for Research Involving Recombinant DNA Mol- 
ecules^ In drafting an impact statement, however, the NlB has given 
further consideration to these issues and has provided an opportunity 
for the public to comment from an environmental perspective. This 
perspective has been extremely helpful in NIH's review of policies 
and procedures on recombinant DNA research. 
