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NOTICES 
9. The dust pan and squeegee should be 
placed in an autoclavable bag and auto- 
claved according to standard directions. 
Contact of reusable items with non auto- 
clavable plastic bags should be avoided — 
separation of the plastic after autoclaving 
can be very difficult. 
C. Radioactive Biohazard Spill Outside a 
Biological Safety Cabinet 
In the event that a biohazardous spill also 
involves a radiation hazard, the clean-up 
procedure may have to be modified, depend- 
ing on an evaluation of the risk assessment 
of relative biological and radiological 
hazard. 
Laboratories handling radioactive sub- 
stances must have the services of a desig- 
nated radiation protection officer available 
for consultation. 
The following procedure indicates sug- 
gested variations from the biohazard spill 
procedure (above) that should be considered 
when a radioactive biohazard spill occurs 
outside a Biological Safety Cabinet.* 
1. Holding your breath, leave the room 
immediately and close the door. 
2. Warn others not to enter the contami- 
nated area. 
3. Remove and put in a container con- 
taminated garments for autoclaving and 
thoroughly wash hands and face. 
4. Wait thirty minutes to allow dissipation 
of aerosols created by the spill. 
* Before clean-up procedures begin, a radia- 
tion protection officer should survey the spill 
for external radiation hazard to determine 
the relative degree of risk. 
5. Put on a long-sleeve gown, mask, and 
rubber gloves before reentering the room. 
(For a high risk agent, a jumpsuit with tight- 
fitting sleeves and a respirator should be 
considered) . 
6. Pour a decontaminant solution (5% 
iodophor or 5% hypochlorite are recom- 
mended) around the spill and allow to flow 
into the spill. Paper towels soaked with the 
decontaminant may be used to cover the 
area. To minimize aerosolization, avoid pour- 
ing the decontaminant solution directly onto 
the spill. 
7. Let stand 20 minutes to allow adequate 
disinfectant contact time. 
8. */n most cases, the spill will involve 
oc or S H, which present no external hazard. 
However, if more energetic beta or gamma 
emitters are involved, care must be taken 
to prevent hand and body radiation ex- 
posure. The radiation protection officer must 
make this determination before the clean-up 
operation is begun. 
If the radiation protection officer approves, 
the biohazard-handling procedure may be- 
gin: Using an autoclavable dust pan and 
squeegee, transfer all contaminated mate- 
rials (paper towels, glass, liquid, gloves, etc.) 
into a deep autoclave pan. Cover the pan with 
aluminum foil or other suitable cover and 
autoclave according to standard directions. 
*lf the radiation protection officer deter- 
mines that radioactive vapors may be released 
and thereby contaminate the autoclave, the 
material must not be autoclaved. In that 
case, sufficient decontaminant solution to 
immerse the contents should be added to the 
waste container. The cover should be sealed 
with waterproof tape, and the container 
stored and handled for disposal as radioactive 
•Changes in procedures have been starred 
and underlined. 
waste. Radioactive and biohazard warning 
symbols should be affixed to the waste con- 
tainer. As a general rule, autoclaving should 
be avoided. 
9. If autoclaving has been approved, the 
dust pan and squeegee should be placed in 
an autoclavable bag and autoclaved accord- 
ing to standard directions Contact of re- 
usable items with plastic bags should be 
avoided — separation of the plastic after auto- 
claving can be very difficult 
•A final radioactive survey should be made 
of the spill area, dust pan, and squeegee with 
a Geiger counter, or a smear should be taken 
and counted in a liquid scintillation counter. 
IX. A SECONDARY RESERVOIR AND FILTRATION 
APPARATUS FOR VACUUM SYSTEMS 
The aspiration of tissue culture media from 
monolayer cultures and of supernatants from 
centrifuged samples into collection vessels or 
reservoirs is a common procedure in many 
laboratories. To prevent the accidental con- 
tamination by aerosols or fluids of house vac- 
uum systems or laboratory pumps, some in- 
, vestigators have Installed side arm flasks 
containing cotton, sulfuric acid or decontam- 
inant between the reservoir and the vacuum 
line. Cotton is not completely effective as a 
filtering agent, sulfuric acid will corrode 
pipes, and decontaminants may lose their 
inactivating ability upon standing. The in- 
troduction of a cartridge-type filter that is 
moisture resistant and has a rated capacity 
to remove particles 350 nm (0.35u) or larger 
in size provides an effective barrier to virus 
aerosols. 
The secondary reservoir and filtration ap- 
paratus can be assembled from readily avail- 
able units as shown in Figure 1. A length of 
plastic tubing % inch I.D. x -fa inch wall 
is attached at one end of the reservoir and at 
the other end to the lower arm of a filtration 
and media storage flask. These flasks vary in 
capacity from 250 to 4000 ml, the choice of 
flask depending on available space and 
amount of fluid that could be accidentally 
aspirated. A second tube of the same di- 
mensions is attached from the upper arm of 
the flask to the inlet port of the disposable 
filter assembly. The third tube is attached 
from the filter assembly to a vacuum source. 
The tubes are securely held to the filter by 
fittings supplied with the filter and the 
other tubing connections can be secured by 
worm drive hose clamps. 
Ideally the flask should be placed higher 
than the reservoir of collection vessel. If fluid 
is accidentally drawn into the flask, the liq- 
uid can drain back Into the reservoir by 
gravity if the connection at the vacuum line 
is broken. This prevents the loss of fluid 
which the investigator needs to retain. 
Should the flask be used only for the re- 
covery and storage of waste fluids, then the 
addition of a few grams of Dow Corning 
Antifoam A to the flask will reduce violent 
foaming of fluids aspirated into it. Such flu- 
ids can be decontaminated by introducing 
into the reservoir a final 5% concentration 
of aja iodophor or other appropriate decon- 
taminant, holding for 30 minutes and drain- 
ing as above. 
If the filter becomes contaminated or re- 
quires changing, the filter and flask can be 
safely removed by clamping the line between 
filter and vacuum source. The filter and flask 
should be autoclaved before the filter is dis- 
carded. A new filter can then be installed and 
the assembly replaced. 
FEDERAL REGISTER, VOL. 41, NO. 131 — WEDNESDAY, JULY 7, 1976 
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