Attachment II - Page 4 
Or. William J. Gartland, Jr. 
September 14, 1983 
Page 4 
The sensitivity of this system is as follows: 
1 organism detected on total of 3 plates plated with the undiluted 
impingement fluid. 
Thus: 1.0 organism per 0.3 ml = 3.3 organisms per ml fluid. 
Liquid volume of impinger = 50 ml . 
Thus: 3.3 organisms per ml x 50 ml = 165 organisms impinged. 
0.44 SCF air tested per min x 5 min sampling period. 
Thus: 165 organisms per 2.2 SCF air tested = 75 organisms per ft 3 
air. 
Minimum sensitivity = 75 E. col i per ft 3 air. 
The challenge was estimated to contain 3.2 x 10^ E. col i per ml. 
Results : 
The only sample to show E. coli was the 30 inch monitoring station 
above a 1000 ml spill. Each plate contained 1, 2, and 2 organisms 
which calculates out to 375 organisms per ft 3 air. It is important 
to note that the 60 inch monitoring station showed no detectable 
E. col i . 
The new proposal consists of a clarifying addition to the paragraphs in 
Appendix C that provide IBC's with authority to approve large scale experiments 
with the exempt host-vector systems. We believe that such clarification will 
avoid several difficulties which could arise from the interpretive aspects of 
Section III B-5 - e.g., whether or not it is "appropriate" to require Pl-LS 
containment for a particular large scale production protocol. The example we 
have chosen to illustrate in the proposals is one which could represent a 
significant process advantage in many recombinant DNA large scale procedures 
utilizing exempt host-vector systems: 
Proposal to Modify Appendix C 
The statements relating to large scale experiments under Appendix C— II, 
C— III, and C-IV should be extended to read as follows: 
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