|
Chapter Nine - Chemical
Safety
Chemical Storage - EH&S Chemical Storage
Recommendations
General (dry)
Chemicals
Dry chemicals which are not acutely highly hazardous may be stored together as long
as they are stored by compatibility group. Acutely highly
hazardous materials must be stored away from other materials in
secure storage. General guidelines for the storage of
chemicals are as follows:
-
All chemicals must be labeled.
-
Hazardous materials must be stored in designated
areas. For example, acids should be stored in designated acid
storage cabinets, flammable materials should be stored in fire-rated
flammable material storage cabinets, etc.
-
Cabinets with metal or glass doors are best
storage for chemicals. Storage of any chemicals on open
shelving is discouraged as containers may be knocked off an open
shelf creating spill conditions.
-
Chemicals may not be stored on unfinished wooden
shelving. Finished metal or high density plastic
(polypropylene) is recommended shelving material for most chemicals.
If wood is used it must be sealed with a good grade oil based paint,
natural or synthetic varnish.
-
If open shelving is used, each shelf must
minimally have a 3/4" lip.
-
No containers of chemicals may be stored on the
floor of a lab room at any time.
-
Do not store chemicals in excessively hot or cold
areas. Both conditions can lead to breakage of containers and
subsequent spillage of their contents.
Flammable Solvents:
Flammable solvents, along with organic acids, and flammable liquid
and solid organic reagents need to be stored separately from other
materials. A rated flammable storage cabinet is the
recommended storage for flammable organic materials. If a
rated storage cabinet is not available, a hood base cabinet or other
tightly closing metal cabinet is acceptable. Flammable
materials should never be stored on the bench top. All
containers of flammable materials must be capped at all times.
No sources of open flames are allowed in areas where flammable
materials are stored. See the attached documents on storage
for additional information.
The National Fire Protection
Association (NFPA) has devised a rating system for flammable and
combustible liquids.
"Information
from NFPA Standards Regarding Flammable and Combustible Liquids",
NFPA 30, Flammable and Combustible Liquids, Section 1-7.3 (p.
30-10) gives a concise definition of flammable liquids based on
boiling point and flash point. All flammable and combustible
liquids are given a rating from Class IA (dangerously flammable) to
Class III (somewhat combustible).
The table "NFPA Classification of
Flammable Liquids" gives the classification of many common lab
solvents and organic reagents. NFPA 45, Fire Protection for
Laboratories Using Chemicals, defines a maximum allowable
container capacity for the various flammable liquids in Table 7-2.
An exception to this table (7-2.3) is that "glass containers as
large as 4 liters (1.1 gallon) shall be permitted to be used if
needed and if the required purity would be adversely affected by
storage in a metal or an approved plastic container, or if the
liquid would cause excessive corrosion of degradation of a metal or
approved plastic container." NFPA 30 additionally proscribes,
in Table 4-4.4.2 (p. 30-35), the quantities of flammable materials
that may be stored in a lab room. These storage requirements
for all Class I and II solvents are based on the size of the room
and whether or not the room is sprinklered. It is important
that these requirements are followed so that excessive storage of
flammable liquids does not lead to dangerous fire situations.
Acids / Bases:
The reaction of acids and bases (corrosives and caustics) tends to
be exothermic, producing heat and aerosols, often in a violent
manner. It is important that acids and bases are stored in
separate cabinets. Acids should be stored in a vented cabinet
if possible. Organic acids, even though they may be corrosive,
(acetic acid, for example) should not be stored with strong mineral
acids. They should be stored with other organic compounds.
Secondary containment is important for strong acids and bases.
Highly Toxic / Carcinogens:
Toxic chemicals and carcinogens need to be stored separately from
other chemicals.
"Cornell University Select Carcinogens" covers
most of the common lab chemicals which are listed carcinogens, but,
may not list all of the carcinogens stored or used in a particular
lab. Another useful document,
"Table
Z-1 Limits for Air Contaminants" taken from OSHA Standard
CFR 1910.1000. Consult with the MSDS for a particular chemical
to determine if it is highly toxic or a carcinogen. See the
attached documents on storage for additional information.
Incompatible Storage:
Incompatible chemical storage is the condition wherein if two or
more containers of chemicals are accidentally mixed, as in the
breakage of containers or a multiple chemical spill, the result is
the liberation of heat, fire, generation of gasses, generation of
substance more toxic than the materials mixed or other undesirable
chemical reactions. As noted in other sections of this manual,
storing incompatible chemicals together can be very dangerous.
It is important that chemicals are always stored by compatibility
group.
Chemicals should never be stored
en masse by the alphabet as this will automatically introduce
chemical incompatible storage situations. Many classes of
incompatible materials may be stored in proximate storage with other
chemicals if secure secondary containment is used to prevent
incompatible reactions. Many incompatible materials can be
located on Cornell's EH&S
"Incompatible Chemical Combinations" web page.
In addition, the MSDS for most materials lists incompatibilities for
that chemical.
Chemical Waste Storage:
Chemical wastes must be treated with the same storage considerations
as the pure chemicals from which the waste is derived. In
addition many regulations apply to the storage and handling of
hazardous wastes:
a. Only compatible wastes
may be stored in the same waste bottle.
b. A waste bottle
must have a green, stick on label provided by Environmental Health
and Safety. The label must be properly filled out.
c.
Waste bottles must be tightly capped at all times, unless material
is being added to or removed from the bottle. Leaving a funnel
in a waste bottle on an on-going basis is a server hazardous waste
regulations violation and carries a $5,000 to $6,000 fine per
container if cited by the EPA or State DEC!!!
d. At Cornell
a waste bottle may be kept only 90 days in a "satellite accumulation
area" (the average lab hazardous waste bottle locations) before it
must be taken away for shipment off campus.
e. Waste
bottles containing acutely hazardous materials must have secondary
containment.
For other information on the
handling and storage of chemicals wastes, see Section 7.0 of the
Cornell University Chemical Hygiene Plan,
"Chemical Waste Disposal Procedures". If you have
a specific question call Harry Dilles or Ed Kowalski at 254-1625.
Additional useful information may be found in the ACS publication,
Laboratory Waste Management: A Guidebook.
Dated Peroxide Formers:
Several classes of organic compounds from peroxides upon standing in
contact with air. Many of these peroxides are very energetic
compounds and may detonate upon being disturbed, such as removing
the cap of a container in which they are found, or evaporating the
peroxide containing compound to dryness. The general
procedures for handling peroxide forming compounds are:
-
Date all containers of peroxide
forming compounds upon arrival. Several manufactures print the
production date or "pull date" of peroxide formers, such as ethyl
ether, on the container.
-
Peroxide forming compounds need to
be tested for peroxides on a specified date after the container is
opened. For example, ethyl ether needs to be tested for
peroxides six months after a container is opened. Test strips
and other methods are available for peroxide determination.
-
If peroxides are detected they
need to be decomposed and the material redistilled to the desired
purity or the chemical should be labeled and picked up for disposal
as hazardous waste.
Test strips are commercially
available and for sale at the Chemistry Department stock room in S.
T. Olin Hall.
Secondary Containment:
The safest way to separate incompatible chemicals is in storage or
use is to secondary containment. A sturdy, durable container,
such as a fiberglass, Nalgene, glass or metal tub or tray is used to
house the chemicals of one compatibility group in a storage cabinet.
Thus, if a container(s) is accidentally broken the secondary
container prevents reactions from starting and contains the spill.
This allows several classes of incompatible chemicals to be stored
together in the same storage cabinets yet eliminates the risk
associated with mutual storage of incompatible materials.
Secondary containment is mandated for radioactive waste containers,
also. Bottle-in-can and similar double packaging is adequate
secondary containment in most instances. It is important that
containers used for secondary containment are compatible with the
materials stored in them.
Re-labeling of Containers:
All chemical containers come with a label. The original label
of most containers purchased in recent years provides detailed
information on the properties and health hazards of the chemical and
should never be defaced or removed unless the container is empty and
well rinsed. All containers should be dated and inventoried
upon arrival. As a general rule, if a material is transferred
from and original container to other containers, such as making a
solution of chemical or repackaging into smaller bottles for
redistribution within a research or teaching lab, all such
containers need to be properly labeled with the full name of the
materials in the container, the concentration if a solution or
mixture and the date, along with the initials of the person
repackaging the chemical.
The OSHA Hazard Communications
Standard and the OSHA Lab Standard have specific requirements for
the labeling of chemicals. In a laboratory covered under the
Lab Standard, if a chemical is designated as a hazardous material,
that is having the characteristics of corrosivity, ignitability,
toxicity (generally meaning a highly toxic material with LD50 of 50
mg/kg or less), reactivity, etc., and if it is made into a solution
or repackaged as a solid or liquid in a concentration greater than
1% (0.1% for a carcinogen) it needs to have a so called
Right-To-Know (RTK) label which duplicates the hazard warnings,
precautions and first aid steps found on the original label.
In a non-lab setting, such as a shop, greenhouse or hospital, the
Hazcom Standard dictates that all repackaged chemicals,
including commercial products which are a mixture of chemicals, need
a RTK label. Without the proper labeling of chemicals as
stated in these two standards a work place is not in compliance with
Federal regulations.
To facilitate compliance with
Federal regulations a label generating program exists to provide
very inexpensive RTK labels for labs at Cornell.
Refrigerated Storage:
Liquids with a flash point below 100 degrees Fahrenheit may not be
stored in an ordinary refrigerator. They may only be stored in
a refrigerator designed and rated for storage of flammable
materials. No food may be stored in a chemical storage
refrigerator at any time. All refrigerators designated for the
storage of chemicals should be labeled "No food storage allowed in
this refrigerator". Please see
"Safe Storage of Chemicals" for information
on the proper use of refrigerators.
Other information:
Cornell EH&S Chemical Storage Recommendations
Last Update:
2006-09-21
|
