COVINGTON a BURLING 
Donald S. Fredrickson, M.D. 
March 3, 1978 
Page Two 
As I stated during the February 1976 meeting and 
in my subsequent letter to you of February 20, 1976, the 
burden of demonstrating to the satisfaction of the public 
that research on recombinant DNA molecules is "safe" (i.e., 
that the level of risk is both reduced as far as is reason- 
ably feasible under the circumstances and does not outweigh 
the potential benefits) rests on those who wish to proceed 
with this research. This is the public policy position 
adopted by Congress with respect to other comparable human 
endeavor. A person who wishes to expose a human being to an 
experimental new drug or food additive, or who wishes to 
bring into commercial production a new chemical substance 
for any use whatever, bears the burden of both informing the 
government of that intention and of submitting sufficient 
information to persuade the government agencies involved 
that the new substance, under the proposed conditions of use, 
has been shown by adequate data to be safe enough to proceed 
with the course of action proposed. It is important to note 
that this public policy is not based upon knowledge, or even 
apprehension, that the proposed action will be unsafe. Rather, 
it is based upon the public policy determination that no new 
substance can be presumed to be safe, and thus that those 
who wish to proceed with any particular new substance must 
first satisfy their burden of demonstrating safety. This 
is in contrast with the public policy that previously pre- 
vailed, under which manufacturers of products of this nature 
were free to market them without first demonstrating safety. 
In the past few years, the public has very deliberately re- 
jected the old policy under which new substances were pre- 
sumed to be safe until proven otherwise, and has adopted a 
new policy under which substances are presumed not to be 
safe until they are shown to be safe. 
The current public policy is thus not a statement 
of scientific fact, but rather is a statement of public 
policy emanating from scientific uncertainty. It embodies 
a conclusion that neither specific humans nor the environment 
should be exposed to new substances until their safety has 
adequately been evaluated. It is not, and could not be, a 
determination that all new substances are unsafe. 
I emphasize the conceptual basis for this public 
policy because many of the comments made at the December 1977 
meeting appeared seriously to misperceive it. The original 
wisdom of the moratorium is not denigrated by subsequent new 
thought and information revealing that some of the initial 
concerns about this type of research are misplaced, any more 
[Appendix A — 240] 
