March 19, 1976 
SELECTED ISSUES FOR COMMITTEE REVIEW 
A. Methods of Containment 
Comments on the containment provisions in the proposed guidelines 
were directed to the definitions for physical and biological 
containment and the safety and effectiveness of the prescribed 
levels of containment. Several commentators found the concept 
of physical containment imprecise and too subject to the possibility 
for human errors. Others questioned the concept of biological 
containment in terms of its safety and purported effectiveness in 
averting potential hazards. 
The commentators were divided on which method of containment would 
provide the most effective and safe system to avoid hazards. Several 
of the commentators suggested that there be a fuller explanation for 
each of the physical containment levels. Dr. W. Emmett Barkley 
convened a committee that has reviewed the section on physical 
containment in response to the suggestions. You will receive that 
committee’s recommendations under separate cover. 
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There are approximately 27 P4 facilities in operation and 9 in 
construction. It has been suggested that the NIH should conduct 
a periodic assessment of these facilities when they are engaged in 
recombinant DNA experiments. The basis for this suggestion is that 
the nature of the experiments conducted at these facilities merits 
special attention by experts having maximum familiarity with the 
structure, operation, and potential problems of such facilities. 
What is the committee’s response to this suggestion? 
B. Prohibited Experiments 
Commentators supported prohibition of experiments listed in the 
guidelines. Comments included suggestions for a clearer definition 
of the prohibition on experiments where antibiotic resistance may 
occur. It was urged by some that the prohibition be broadened to 
include experiments that result in resistance to any antibiotic 
irrespective of its use in medicine or agriculture. In this regard, 
I ask that the committee consider three separate sections of the 
guidelines that relate to the question of antibiotic resistance. 
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