V. CONTROL MEASURES
1. Laboratory ventilation is normally designed to provide
eight air changes per hour. This flow is not necessarily
sufficient to prevent accumulation of chemical vapors.
Laboratory work shall be conducted in a fume hood, glove
box, or similar device when:
a. Procedures call for work with toxic substances
which are volatile; i.e., evaporate at normal
temperature and pressure, or
b. There is a possibility the action level or PEL
(see Appendix III) will be exceeded.
2. The protection provided by the laboratory fume hoods
is dependent upon two important factors:
a. proper use of the hood, and
b. maintenance of adequate airflow through the hood.
3. The way the hood is used will determine the degree of
protection it will provide. Each employee is responsible
for implementing the following work practices when
using a hood.
a. Continually monitor air being drawn into the hood
by attaching a kim wipe or light-weight strip of
paper to the bottom of the sash.
b. Operate the hood at the proper sash position;
i.e., maximum 12 inch sash height for hoods with
vertical sliding (up and down) sashes and the
sashes closed as much as possible for hoods with
horizontal sliding (left and right) sashes. This
helps to ensure optimum protection when conducting
operations in the hood. A small sash opening maximizes
air velocity through the hood face and may provide
additional protection from unexpected splashes or
c. Avoid using the hood for storage of bottles and
equipment, especially along the back wall. Any
apparatus that must be housed within the hood should
fit completely inside the hood. Elevate the apparatus
on blocks (at least 2 inches off the benchtop) to
allow air to flow freely around and beneath.
d. Manipulations within the hood should be performed at
least 6 inches inside the face of the hood or as far
towards the back of the hood as possible. This minimizes
the possibility of contaminants escaping from the hood.
e. Fully close the hood sash and turn off the fan
(if possible) when the hood is not in use. The fan
should remain on if volatile materials are being
temporarily (i.e., for the duration of a current
project) stored in the hood.
f. Things which cause air turbulence across the face of
the hood such as fans, window air conditioning units,
or excessive movement should be avoided.
g. Exhaust hoods do not provide adequate protection for
all operations involving toxic materials. A higher level
of containment should be used for procedures where
minor contamination can be serious. If you are in
doubt about the level of containment needed for
operation, ask your PI or contact the CHO.
4. EHSO conducts annual surveys of fume hoods to ensure
adequate airflow is maintained through the hood face.
Face velocities should be between 80 and 120 feet per
minute (fpm). Hoods that do not meet these minimum
standards are considered "inadequate" and should not
be used for protection from toxic or volatile materials.
Contact EHSO at x65180 if you suspect the hood is not
5. At no time shall laboratory fume hood alarms be tampered
with or disabled. Upon activation of the alarm work within
the hood should cease and facilities and/or the EHSO must
B. SPILL CLEAN-UP PROCEDURES
The range and quantity of hazardous substances used in laboratories
requires preplanning to respond safely to chemical spills. The
cleanup of a chemical spill should only be done by knowledgeable
and experienced personnel. Spill kits with instructions, adsorbents,
reactants, and protective equipment should be available to clean up
minor spills. A minor spill is one that does not spread rapidly,
does not endanger people or property except by direct contact,
does not endanger the environment, and the laboratory staff is
capable of handling safely without the assistance of safety and
emergency personnel. All other chemical spills are considered
major and EHSO must be notified at x63202. In the event of a
minor spill the following procedures shall be carried out:
1. Attend to anyone who may have been contaminated or hurt.
2. Ensure that the fume hood(s) is on. Open windows where
possible to increase exhaust ventilation and if the spilled
material is flammable, turn off all ignition and heat sources.
3. Secure cleanup supplies. Neutralize acids and bases, if
possible. Ensure protective apparel is resistant to the
4. Control the spread of the liquid by containing the spill.
5. Absorb the liquid by adding appropriate absorbent materials
from the spill's outer edges toward the center.
6. Collect and contain the cleanup residues by scooping it into
a plastic bucket or other appropriate container.
7. Properly dispose of the waste as hazardous waste.
8. Decontaminate the area and affected equipment. Ventilating
the spill area may be necessary.
9. Document what happened, why, what was done, and what was
learned. Such documentation can be used to avoid similar
instances in the future. Major incidents are almost always
preceded by numerous near misses.
In any event, there should be supplies and equipment on hand to deal
with the spill, consistent with the hazards and quantities of the
spilled substance. These cleanup supplies should include neutralizing
agents (such as sodium carbonate and sodium bisulfate) and absorbants
(such as vermiculite and sand). Paper towels and sponges may also be
used as absorbent-type cleanup aids, although this should be done
cautiously. For example, paper towels used to clean up a spilled
oxidizer may later ignite, and appropriate gloves should be worn
when wiping up highly toxic material with paper towels. Also, when
a spilled flammable solvent is absorbed in vermiculite or sand, the
resultant solid is highly flammable and gives off flammable vapors
and, thus, must be properly contained or removed to a safe place.
If you have questions regarding spill clean up requirements please
contact EHSO at x63198.
In the event of a major spill the following procedures shall be
1. Attend to anyone who may be hurt or contaminated if it
can be accomplished without endangering yourself.
2. If flammable materials are spilled, de-energize
electrical devices if can be done without endangering
3. Call Campus Security at x66911.
C. CLOSE-OUT PROCEDURES FOR DEPARTING/RETIRING FACULTY AND
Proper disposition of all hazardous materials used in laboratories
is primarily the responsibility of the PI or researcher to whom a
laboratory is assigned. Safe disposition of hazardous materials
is required whenever a PI or researcher leaves the University or
transfers to a different laboratory. The following procedures
should be completed when a Principle Investigator or researcher
leaves the University or transfers to a different laboratory.
1. Assure that all chemical containers are labeled with
the name and hazard. All containers must be securely
closed. Beakers, flasks, vials, evaporating dishes, etc.
must be emptied and the contents properly disposed.
Remember to check refrigerators, freezers, cold rooms,
fume hoods, biological safety cabinets, bench tops, storage
cabinets, stock rooms, etc.
One of the most problematic situations is the sharing of storage
units such as refrigerators, freezers, cold rooms, stock rooms, etc.,
particularly if no one has been assigned to manage the space. Shared
spaces must be properly surveyed in order to locate and appropriately
dispose/designate remaining chemicals.
2. Determine which chemicals are usable and transfer responsibility
for these materials to another party who is willing to take
charge of them. If a new user cannot be found, the materials
should be disposed.
3. Controlled substances must be disposed of as specified by the
DEA permit under which it is held. Abandonment of a controlled
substance is a violation of the Drug Enforcement Agency (DEA)
requirements. Permission to transfer ownership of a
controlled substance to another individual must be received
4. Remove compressed gas cylinder connections, replace cylinder
caps, and return cylinders to suppliers. If cylinders are
non-returnable, contact the Hazardous Materials Management
Program at x63198.
5. If laboratory equipment will be left for the next occupant,
clean or decontaminate it before departing the laboratory.
6. If laboratory equipment will be discarded, be aware that
capacitors, transformers, mercury switches, mercury
thermometers, radioactive sources and chemicals must
be removed prior to disposal. Contact the EHSO for assistance.
7. Wash off fume hood surfaces and bench tops.
8. Prepare chemicals targeted for hazardous waste disposal by
following procedures in Appendix VII. This process should
be started at least a month before departure from the
laboratory to allow ample time to properly dispose all
materials. Hazardous waste pickup should be completed before
the laboratory is vacated. Contact the EHSO Hazardous Materials
Management Program at x63198.
9. Notify the department Chair and the Chemical Hygiene Officer
at x65180 when the laboratory has been cleared.