Copy of letter to Congressional Committees 
DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE 
PUBLIC HEALTH SERVICE 
NATIONAL INSTITUTES OF HEALTH 
BETHESDA, MARYLAND 20014 
June 23, 1976 
See Attached List of Addressees 
Dear 
Enclosed is a copy of the NIH guidelines on recombinant DNA research 
and my decision which accompanies them. 
The NIH Guidelines will govern research at laboratories of the NIH and 
those of its grantees and contractors. The NIH has also undertaken an 
environmental impact assessment of these Guidelines for recombinant 
DNA research in accordance with the National Environmental Policy Act 
of 1969. The purpose of this assessment is to review the environmental 
effects, if any, of research that may be conducted under the Guidelines. 
Recombinant DNA molecules result from recombination in the test-tube 
of segments of deoxyribonucleic acid, the material which determines 
the hereditary characteristics of all living cells. These techniques have 
a remarkable potential for furthering the understanding of fundamental 
biochemical processes in cells of lower and higher organisms, and 
promise to revolutionize molecular biology. But the technology, which 
permits genetic information from very different organisms to be 
combined, also involves potential hazards which are difficult to evaluate. 
Therefore the research must proceed with considerable caution. 
Medical advances to be expected through the use of this technology 
include the opportunity to explore the functioning of cells in com- 
plicated diseases. Understanding of a variety of hereditary defects may 
be significantly enhanced, and some may be able to be prevented or 
modified. In the future it may be possible to use this technology to 
produce in microorganisms medically important compounds for the 
treatment and control of disease. 
There are risks in the new research as well as potential benefits. 
Microorganisms with transplanted genes--called "chimeras "--may prove 
hazardous to human or other forms of life. Thus special provisions are 
necessary for their containment. 
The NIH Guidelines establish carefully controlled conditions for the 
conduct of experiments involving the production of such molecules and 
their insertion into organisms such as bacteria. These Guidelines 
