NOTICES 
27935 
removing wastes from tanks In case broken 
glass is present. After making the filter 
changes, all external surfaces of the im- 
mediate work area and the equipment should 
be wiped with a cloth moistened In decon- 
taminant. The operator might plan for a 
change of laboratory clothing afterwards so 
as to minimize carrying contamination into 
other areas of the laboratory. 
Avoid use of dry vacuum cleaning equip- 
ment in work with high risk agents in the 
open laboratory. Should it be necessary to 
use it, it is recommended that gaseous 
sterilization be used to minimize aerosoli- 
zation of microorganisms before waste is 
emptied from the vacuum container. Be- 
cause complete penetration of sterilizing 
gases into the collected dry dust may be a 
problem, all wastes should be placed in a 
plastic bag, which then is tightly closed and 
incinerated or disposed of in an approved 
manner. 
When dry vacuum cleaning equipment has 
been used within a gastight safety cabinet 
system, it can be treated in an attached 
double-door carboxyclave (an autoclave 
equipped with an ethylene oxide gas sterili- 
zation system) to allow for removal and 
emptying of the collection tank. 
If a wet vacuum is to be used for pickup 
of the detergent-germicide solution from the 
floor, the manufacturer's recommendations 
on filter life should be followed. In addition, 
the operation of the vacuum should be 
closely observed for evidence of operating 
changing indicating restricted airflow or, 
conversely, increased flow indicating filter 
failure. Liquids collected in the vacuum 
cleaner after floor mopping will contain de- 
contaminant material. These liquids may be 
poured down a convenient floor drain, ex- 
cept in the case of cleanup wastes from an 
overt spill. The collected liquid should then 
be autoclaved or treated with chlorine solu- 
tion before disposal. 
Provisions should be made for regular de- 
contamination of the entire vacuum cleaner 
with formaldehyde gas or vapor, or ethylene 
oxide. This should be done after use if the 
vacuum is used in any manner for cleanup 
of overt spills of infectious material. 
E. Selection of a Cleaning Solution ' 
The selection of a detergent-decontam- 
inant combination for routine cleaning of 
the laboratory complex should be based on 
the requirements of the area of greatest po- 
tential for contamination by the widest 
spectrum of microorganisms. With rare ex- 
ception, this will be identified as the animal 
holding area and the expected microorga- 
nisms. With rare exception, this will be iden- 
tified as the animal holding area and the 
expected microorganisms may well include 
fungi, viruses, and the vegetative and spore 
forms of bacteria. A decontaminating solu- 
tion for such a range of microorganisms 
would, however, be expensive and excessively 
corrosive for routine use. Except in those rare 
instances where it can be assumed that path- 
ogenic spores are being, shed by laboratory 
animals, the risks from the spores are more 
likely to affect the experiments than the 
personnel. The spores tend to be associated 
with organic debris from bedding and food, 
thus offering potential for removal or at 
least a large initial reduction in their num- 
bers by vacuum cleaning. A wide range of 
cleaning solutions that are mildly sporicidal, 
reasonably residual, and are not destructive 
to the physical plant are available. Phenol 
derivatives in combination with a deter- 
gent have these characteristics and have been 
selected for routine use in a number of 
research facilities. There are numerous de- 
tergent-phenolic combinations available on 
the market. The phenols are one type of a 
broad spectrum of biocidal substances that 
includes the mercurials, quaternary am- 
monium compounds, chloride compounds, 
lodophores, alcohols, formaldehyde, glutar- 
aldehyde, and combinations of alcohol with 
either iodine or formaldehyde. These have 
been discussed in. Section VI. 
The laboratory supervisor should make a 
selection from those types most readily avail- 
able which meet the general criteria of 
effectiveness, residual properties, and low 
corrosiveness. 
F. Wet^ Mopping — Two-Bucket Method 
Wet mopping of floors in laboratory and 
animal care areas is, from a safety stand- 
point, most conveniently and efficiently ac- 
complished using a two-bucket system. The 
principal feature of such a system is that 
fresh detergent-decontamlnant solution is 
always applied to the floor from one bucket, 
while all spent cleaning solution wrung from 
the mop is collected in the second bucket. 
Compact dolly-mounted double-bucket units 
with foot-operated wringers are available 
from most janitorial supply houses. A freshly 
laundered mop head of the cotton string 
type should be used daily. This requires that 
a mcp with removable head be provided as 
opposed to a fixed-head type. In practice, 
the mop is saturated with fresh solution, 
very lightly wrung into the second bucket 
and applied to the floor using a figure eight 
motion of the mop head. After every four 
or five strokes, the mop head is turned over 
and the process continued until an area of 
approximately 100 ft 2 has been covered. After 
allowing a contact time of five minutes, the 
solution is removed with either a wet vacuum 
cleaner with HEPA-filtered exhaust or with 
the wrung-out mop. The mopping is con- 
tinued in 100 ft 2 increments until the total 
floor area has been covered. Floor-cleaning 
procedures are most effectively completed 
after the majority of the work force has 
departed and should progress from areas of 
least potential contamination to those of 
greatest potential. Before a mop head is sent 
to a laundry, it should be autoclaved. Spent 
cleaning fluids are disposed of by flushing 
down the drain. 
■If the cleanup follows an overt spill of 
infectious material, the spent cleaning so- 
lution, after removal from the floor, should 
be autoclaved or treated with chlorine solu- 
tion. Chlorine (as household bleach) should 
be added to give 500 ppm and held for a con- 
tact time of 15 minutes before dumping in 
the sanitary sewer. 
G. Alternative Floor Cleaning Method for 
Animal Care Areas and Areas with Mono- 
lithic Floors 
The absence of permanently placed labora- 
tory benches and fixed equipment, coupled 
with the mobility of modern cage racks, 
makes possible alternate floor-cleaning pro- 
cedures in animal care facilities. As in all 
considerations of methodologies in biomedi- 
cal laboratory facilities, it is necessary to 
assess the compatibility of procedures and 
facilities from the hazard point of view. The 
alternative floor-cleaning procedure to be 
discussed requires that floors are completely 
sealed or of monolithic construction so that 
liquid leakage to adjacent areas does not 
occur and that floor drains or wet vacuum 
cleaners are available. 
Subsequent to the removal of all debris by 
dry vacuum, move the cage racks to one side 
of the room. Cover the floor of the remaining 
cleared portion of the room with detergent- 
decontaminant solution applied at a rate of 
approximately one gallon per 144 ft 2 from a 
one-gallon tank sprayer, using a setting of 
the nozzle which will cause the solution to 
flow on and not create a spray. The nozzle Is 
placed close to the floor. Allow a fifteen- 
minute contact period; then push the clean- 
ing solution to the floor drain with a large 
floor squeegee or pick it up with a wet 
vacuum. Allow the flow to air dry; move the 
cage racks into the cleaned area, and repeat 
the process for the remaining floor area. 
Floor drains In these areas should be rim- 
flush, at least six inches in diameter, and 
fitted with a screen or porous trap bucket to 
catch large debris that escapes the initial 
dry cleaning. Such screens and baskets 
should be emptied after treatment with a 
decontaminant. If space utilization does not 
require frequent floor washdown, pour a 
half-gallon of detergent-decontaminant so- 
lution into the drain each week to keep the 
trap in the waste line filled against backup 
of sewer gases. 
VIII. CLEAN-UP OF BIOHAZARDOUS SPILLS 
( 8 , 9 , 10 ) 
A. Biohazards Spill in a Biological Safety 
Cabinet 
Chemical decontamination procedures 
should be initiated at once while the cabinet 
continues to operate to prevent escape of 
contaminants from the cabinet. 
1. Spray or wipe walls, work surfaces, and 
equipment with a 2% solution of an iodo- 
phor-decontaminant (Wescodyne or equiva- 
lent). A decontaminant detergent has the 
advantage of detergent activity, which is im- 
portant because extraneous organic sub- 
stances frequently interfere with the reac- 
tion between the microorganisms and the 
active agent of the decontaminant. Operator 
should wear gloves during this procedure. 
2. Flood the top work surface tray, and, if a 
Class II cabinet, the drain pans and catch 
basins below the work surface, with a de- 
contaminant and allow to stand 10-15 
minutes. 
3. Remove excess decontaminant from the 
tray by wiping with a sponge of cloth soaked 
in a decontaminant. For Class II cabinets, 
drain the tray into the cabinet base, lift out 
tray and removable exhaust grille work, and 
wipe off top and bottom (underside) surfaces 
with a sponge or cloth soaked in a decon- 
tamiant. Then replace in position and drain 
decontaminant from cabinet base into ap- 
propriate container and autoclave according 
to standard procedures. Gloves, cloth or 
sponge should be discarded in an autoclave 
pan and autoclaved. 
B. Biohazard Spill Outside a Biological 
Safety Cabinet 
1. Hold your breath, leave the room im- 
mediately, and close the door. 
2. Warn others not to enter the contami- 
nated area. 
3. Remove and put into a container con- 
taminated garments for autoclaving and 
thoroughly wash hands and face. 
4. Wait 30 minutes to allow dissipation 
of aerosols created by the spill. 
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 wrists and use of 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 
pouring the decontaminant solution directly 
onto the spill. 
7. Let stand 20 minutes to allow an ade- 
quate contact time. 
8. 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 direc- 
tions. 
FEDERAL REGISTER, VOL. 41, NO. 131 — WEDNESDAY, JULY 7, 1976 
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