94 
to work with in these laboratories, there are apt to be more spills than 
if one is able to work with greater ease, even in a PI laboratory. 
I would like in this regard to ask Dr. Barkley, who tells us there 
are at least 27 P4 labs around the country, how many of these are really 
functioning so that there is the absolute control that they are poten- 
tially capable of performing? 
DR. BARKELY: To my knowledge at this time, I don't know of one of 
the laboratories that is currently being operated as a P4 operation; that 
is, that a full-clothing change is being carried out or all the materials 
are isolated. I don't think that the Frederick Cancer Research Center at 
this time is operating at the P4 level. 
DR. MELNICK: What is the point then of trying to raise our level to, 
say, P4 containment if it is so difficult to work in a P4 unit that the 
containment that it should carry or be capable of performing is not being 
carried out? 
DR. FREDRICKSON: Do you want to respond to that. Dr. Barkley, or 
Dr. Berg? 
DR. BARKLEY: I would just like to say that there are a number of 
agents that require P4 control, and if it were of interest to conduct 
studies on them they would be placed in P4 facilities. I do know that 
at the Center for Disease Control they plan to initiate new studies on 
the Lassa virus. Now, that work will be confined to a P4 glove-box opera- 
tion totally, and it would not be considered to work under conditions 
less than that. So it really depends on whether people are doing research 
that requires this. 
DR. FREDRICKSON: What you are saying then. Dr. Barkley, is that these 
facilities exist and relatively moderate procedural changes would be re- 
quired to get them into operation at the P4 level. Is that correct? 
DR. Barkley: Yes, that is correct. 
DR. FREDRICKSON: Dr. Berg, you have a comment on that? 
DR. BERG: I would like to comment on two issues that were raised 
by Dr. Petersdorf and Dr. Melnick. 
I think Dr. Petersdorf is quite correct in pointing out that JE. coli 
is a very low-degree pathogen, and I think the fact is that biochemists 
and molecular biologists have grown up enjoying the use of them primarily 
and have become so familiar with them because they don't worry about dan- 
gers. I think we are not worried about EL coli infecting people. We are 
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