Dr. William J. Gartland, Jr. 
September 14, 1983 
Page 3 
attachment II - Page 3 
Experiment 
I ID 
Before 
1.93 
x 
10 3 
o rg/SCFA 
After 
0 
org/SCFA 
Removal 
>1.93 
X 
10 3 
org/SCFA 
(100% removal) 
Expe riment 
IIE 
Before 
8.20 
X 
10 S * 2 * 
org/SCFA 
After 
2.8 
X 
10° 
org/SCFA 
Removal 
8.19 
X 
10 2 
org/SCFA 
(99.97% removal) 
As these data show, two relatively inexpensive exhaust air treatment devices 
can dramatically reduce the level of entrained microorganism in the exhaust 
air stream. By placing these devices in series in the exhaust line, then 
greater than 99.98% of the entrained cells are effectively maintained within 
the fermentor. We, thus, have succeeded in "minimizing" the aerosol formed in 
the exhaust gas and have provided data to support an amended Appendix K-II-D 
guideline that currently requires that gases be filtered with HEPA quality 
filters or equivalent procedures to prevent the release of viable organisms . 
. . to the environment. 
3. 
Workplace ventilation conditions are sufficient to protect operators 
rom appreciable aerosol inhalation even above sizeable spills of 
^coj_-K12 suspensions. The level of aerosol formation caused by 
spills of various sizes was examined. The site chosen to do the 
experiment was the production fermentor house, second floor since 
ventilation, which is normally good throughout the buildinq, is 
on°th is ?Ur hlS fl °° r ' Also ’ the relative humidity is normally high 
S 1 ]? ° f ° m1 ’ 10 ml > 100 ml > and 1000 ml (3 x 10 9 organisms/ml) 
(spilled from height of 48 inches and of 10 second duration) were 
monitored with air impingers (which operate at an air flow of 0.44 
Ol-M) set 30 and 60 inches above the spill and offset to one side by 12 
inches. Each spill was replicated twice. Sampling occurred for five 
minutes. 
[ 355 ] 
