Chemical storage
BACKGROUND
• Fire
and explosion are only two of the many hazards.
• Over
500 chemical-storage incidents were over the past 5 years.
• These
incidents occurred due to unsafe chemical storage practices.
Storage-related incidents
• Principal causes:
• 1.
Improper or non-existent labeling of chemicals in storage.
• 2. Storage of chemicals beyond the recommended
shelf-life.
• 3.
Degradation of chemical storage containers. ("Polyethylene Bottles
Containing Corrosive Chemicals May Deteriorate With Prolonged Use,"
IMPROPER LABELING
•
Small amounts of
"left-over" chemicals had accumulated over several years.
•
The chemicals
were prepared for recycling or disposal by removing the chemicals from their
individual containers and putting them into a plastic bucket.
•
Powder that was thought to be a base material
was poured from an unlabeled jar into the bucket, resulting in spontaneous
ignition.
•
The building then
had to be evacuated, and the fire department was summoned to put out the fire.
•
Analysis performed by the laboratory later
revealed that the powder was maleic anhydride,
EXTENDED TIME IN STORAGE
•
During a
site-wide Occupational Safety and Health Administration (OSHA) label audit
industrial hygienists
•
found a total of
21 containers of ether which had been stored for over 2 years.
•
.Unrefrigerated
ether cannot be stored safely for over 6 months because peroxides, which are
shock-sensitive, can form and cause an explosion.
•
The building that housed the 18 ether
containers had to be evacuated, and barricades had to be assembled to protect
flammable inventory.
•
The peroxides
were then neutralized with ferrous sulphate, and all 21 containers were
removed.
•
Periodic
inspection and removal of outdated chemicals in storage would have prevented
the incident.
Storage rules
•
Label all chemicals.
The name and address of the manufacturer or other responsible party must be
listed on the label. Chemicals with a shelf life should be labeled with the
date received.
•
Store chemicals
in the locations recommended (i.e., where the temperature range, vibration, or
the amount of light does not exceed the manufacturer's recommendations). Make
sure that chemicals that are stored together are compatible.
Storage rules
3. Inspect annually all chemicals in stock and
storage.
4. Hazardous chemicals should be inspected
every 6 months.
5. Some hazardous chemicals may require more
frequent inspections.
6. Any outdated materials should be properly
disposed of or replaced if necessary
Rules
7. Keep only enough
inventory necessary for uninterrupted operation.
8. Chemical inventory should
be maintained at a minimum to reduce fire, exposure, and disposal hazards
9. Rotate new shipments of
chemicals with existing stock so that the oldest stock is available first.
Storing Acids
•
Store large
bottles of acids on low shelf or in acid cabinets.
•
Segregate
oxidizing acids from organic acids, flammables and combustible materials.
•
Segregate acids
from bases and active metals such as sodium, potassium, etc.
•
Use bottle
carrier for transporting acid bottles.
•
Have spill
control pillows or acid neutralizers available in case of spill.
Strong Oxidizing Acids
• Chromic
Acid
• Nitric
Acid
• Hydrobromic
Acid
• Perchloric
Acid
• Iodic
Acid
• Sulfuric
Acid
Organic Acids
• Acetic
Acid
• Phenol
• Benzoic
Acid
• Trichloracetic
Acid
Storing Bases
• Segregate
bases from acids
• Store
solutions of inorganic hydroxides in polyethylene containers.
• Have
spill control pillows or caustic neutralizers available for spills.
Bases
• Ammonium
Hydroxide
• Calcium
Hydroxide
• Bicarbonates
• Potassium
Hydroxide
• Carbonates
• Sodium
Hydroxide
Flammable
•
Store in approved
safety cans or cabinets
•
Segregate from
oxidizing acids and oxidizers.
•
Keep away from
any source of ignition: flames, heat or sparks.
•
Know where fire
fighting equipment is stored and how to use.
•
If volatile flammable
liquids are stored in a refrigerator it must be in an explosion-proof
(lab-safe) refrigerator.
Flammable Solids
• Benzoyl
peroxide
• Phosphorous,
yellow
• Calcium
Carbide
• Picric
Acids
Flammable Gases
•
Acetylene
•
Ethylene Oxide
•
Ammonia
•
Formaldehyde
•
Butane
•
Hydrogen
•
Carbon Monoxide
Storage of Oxidizers
• Store
in a cool, dry place.
• Keep
away from flammable and combustible materials, such as paper or wood.
• Keep
away from reducing agents such as zinc, alkaline metals, formic acid.
Oxidizers - Solids
•
Ammonium Dichromate
•
Nitrates
•
Ammonium
Perchlorate
•
Ammonium
Persulfate
•
Benzoyl Peroxide
•
Bromates
•
Calcium
Hypochlorite
•
Chlorates
•
Chromium Trioxide
•
Ferric Trioxide
•
Ferric Chloride
•
Hypochlorite
•
Iodine
Pyrophoric Substances:
•
These ignite spontaneously
on contact with air. Store in a cool, dry place.
Light Sensitive Chemicals
•
Avoid exposure to
light & Store in amber bottles in a cool, dry place.
Carcinogens
• Label
all containers as Cancer Suspect Agents.
• Store
according to hazardous nature of chemicals, e.g., flammable, corrosive.
• When
necessary, store securely.
Carcinogens
• Antimony
compounds
• Acrylonitrile
• Arsenic
compounds
• Benzene
• Benzidine
• Chloroform
• Beryllium
• Dimethyl Sulfate
Chemical Segregation and Storage Groups
•
Stanford Storage Group Classification System
• used
to segregate chemicals stored in the laboratory.
• It
is based on physical and chemical reactivity information found in the MSDS or
other references.
Storage Groups
• Storage
Groups are groups of chemicals that will not react violently if mixed together.
• Stanford
has about 10,000 unique chemicals classified according this system in the SCIMS
Database.
• The
Stanford Storage Group system was developed for laboratory scale storage
STANFORD COMPATIBLE STORAGE GROUP CODES
•
A letter
designation is given to each compatible group of materials.
•
For example,
"A" represents "compatible organic bases, flammables and
poisons".
•
"G" is
"not intrinsically reactive, flammable or combustible".
•
A chemical that
is incompatible with other chemicals in all of the other Storage Groups must be
placed in Storage Group "X". Storage Group "X" chemicals
must be segregated from all other chemicals.
•
If the information is not available, then
Storage Group "U" will be assigned.
SEGREGATE CHEMICALS BY COMPATIBLE STORAGE
GROUPS
• Segregate
chemicals in a compatible fashion according to the compatible Storage Groups.
• If
a particular item does not yet have a storage group designated, the researcher
must use his best judgement on how best to store the
material.
• Keep the different storage groups in separate
cabinets, if possible.
SEGREGATE CHEMICALS BY COMPATIBLE STORAGE
GROUPS
• In
areas that contain items from more than one storage group, there is no need to
store them alphabetically by storage group (i.e. A then B then C). The letters
are just an arbitrary convention.
SEGREGATE CHEMICALS BY COMPATIBLE STORAGE
GROUPS
•
If you must store
items from more than one storage group on the same shelf, they must have separate
secondary containment for each group.
•
For example:
– Acetic acid (Storage group "D", organic
acid)
– Hydrochloric acid (Storage group "F",
inorganic acid)
– Nitric acid (Storage group "E",
oxidizing)
•
These all acids but
they are incompatible and must be stored in separate secondary containment and
on separate shelves within the same cabinet.
SEGREGATE CHEMICALS BY COMPATIBLE STORAGE
GROUPS
SEGREGATE CHEMICALS BY COMPATIBLE STORAGE
GROUPS
Store in same cabinet
• If
you must store items from many storage groups in the same cabinet with more
than one shelf,
• put storage group "B" and
"X" on the top shelf.
• This
will prevent other chemicals from dripping on them.
Flammable liquid storage
• If
the total quantity of flammable liquids exceeds 5 Lt, they must be stored in a
flammable liquid storage cabinet except when in active use.
OTHER STORAGE CONSIDERATIONS:
•
Long-term storage
on bench tops or in fume hoods is discouraged.
•
All containers
MUST remain closed except when actively adding or removing materials. Do not
store funnels in open containers.
•
Never store
hazardous materials next to or above sinks. This includes dark rooms with waste
fixer stored adjacent to open floor drains.
OTHER STORAGE CONSIDERATIONS:
• Store
solids above liquids.
• Avoid
exposing stored chemicals to building heat or to direct sunlight.
• All
chemical storage shelving must have lips and seismic restraints.
• Use
explosion-proof refrigerators when storing flammables in a refrigerator.
