- 2 - 
Item 1-4 
To reiterate our position, we feel that the Pl-LS recommendations should 
be the minimum requirements for handling large volumes of recombinant 
organisms’! Thus, we oppose the modification proposed by NIH staff which 
merely "recommends" Pl-LS containment for such applications. In addition, to 
assure that host-vector systems which are exempt at the laboratory scale are 
included in this section, the following modification of the Large Scale Review 
Working Group's proposal is offered: 
The Pl-LS level of physical containment is required for large-scale 
research or production of viable organisms containing recombinant DNA 
molecules for which PI containmment is required or recommended at the 
laboratory scale. (See Appendix C). 
Thank you for the opportunity to comment. 
Sincerely yours. 
/tb 
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