SBMS07_StorageofIncompatibleChemicals_Final_Dec09
SBMS07:
Guidance on Storage of Hazardous Chemicals
If incompatible chemicals are inadvertently mixed a fire, explosion, or toxic release
can easily occur thus it is particularly vital that chemicals be stored safely. This
document contains some basic guidelines for chemical storage. Note however, that
chemicals can often fall into more than one hazard category and therefore the
chemical label and/or Material Data Safety Sheet (MSDS-see below) should be
reviewed for specific storage requirements and when completing COSHH and
DSEAR assessments etc.
In General:
1. Chemicals should be dated upon receipt and when opened, as some have
limited shelf life and others can form dangerous decomposition products (see
http://www.safety.ed.ac.uk/resources/General/Ethers_storage_detection.shtm
for further details)
2. Separate incompatible chemicals by adequate distance, or preferably by
using physical barriers (e.g. storage cabinets).
3. Avoid using the fume hood for chemical storage - this practice may interfere
with the proper air flow of the hood.
4. For especially hazardous materials, use a secondary container (e.g. plastic
tub) large enough to contain a spill of the largest container.
5. Ensure storage, use and disposal are considered in a risk assessment (e.g.
COSHH and/or DSEAR) BEFORE ordering substances so any additional
precautions can be put into place before the material is on site.
Specific advice : (List of approved workplace exposure limits)
1. FORMALDEHYDE
Also called methanal, methalaldehyde (in aqueous solution called
Formalin).
Exposure to 19 mg m-3 vapour concentration causes nasal passage
cancers in rats. Skin cancers occurred at 8 ppm.
The Workplace exposure limit (WEL) is 2.5mg/m3, although even at
1mg/m3 it irritates eyes and nose.
It sensitises the skin causing painful swelling.
It also causes difficulty in breathing after prolonged exposure.
The WEL is the same for short-term (15 min) and long-term (8 h)
exposures.
Keep exposure to formaldehyde to a minimum.
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1.1. BIS-(CHLOROMETHYL)-ETHER (Cl CH2 OCH2 Cl):
Under some conditions formaldehyde can react with hydrogen
chloride (HCl) to form bis-(chloromethyl)-ether : a potent lung cancer
agent in man. WEL (8 h) 0.005 mg m-3.
It is advised that HCl and formaldehyde are NOT stored together and are only
used together under strictly controlled conditions, for example within a fume
cupboard or a fully enclosed system.
Labelling
Formaldehyde containers should be treated as a 'suspect carcinogen'. It is also
recommended that a further label is used wherever practicable:
"FORMALDEHYDE:
DO NOT STORE WITH HCl - [risk of formation of bis-(chloromethyl)-ether]"
2. Ether
Owing to its volatility and extremely low flashpoint temperature of – 40oC , Ether
(diethyl ether, ethyl ether) is one of the greatest fire hazards commonly encountered
in the laboratory; it is classed as extremely flammable (F+).:
See http://www.safety.ed.ac.uk/newsflashes/incidents/incident24.shtm for
details of an incident that occurred within the University.
Ether does not require a source of ignition such as a naked flame, or spark to
initiate combustion. Ether vapour may be ignited by hot surfaces such as hot
plates, electric lamps and static electricity discharges, and since the vapour is
heavier than air, it may travel a considerable distance to an ignition source and flash
back. Sufficient static electricity to initiate flash ignition can build up when large
quantities of ether is being poured from one vessel into another. Ether vapour forms
explosive mixtures with air at concentrations of 1.7% to 48% (by volume). Carbon
dioxide or dry powder extinguishers should be used for ether fires.
Ethers absorb and react with oxygen from the air, in the presence of light, forming
unstable peroxides that can detonate with extreme violence when they become
concentrated through evaporation or distillation and disturbed by heat, shock or
friction. For more information on peroxides, please see
http://www.safety.ed.ac.uk/resources/General/Ethers_storage_detection.shtm
Ether has been assigned the following EU Safety Phrases:
S9 Keep container in a well ventilated place
S16 Keep away from sources of ignition
S29 Do not empty into drains
S33 Take precautionary measures against static discharges
and the following EU Risk Phrases:
R12 Extremely flammable
R19 May form explosive peroxides
R22 Harmful if swallowed
R66 Repeated exposure may cause skin dryness or cracking
R67 Vapours may cause drowsiness and dizziness
The following tables summarise storage precautions for the commonly used
chemicals in the laboratory.
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ACIDS BASES
Acetic Acid Hydrofluoric Acid Ammonium Hydroxide
Chromic Acid Nitric Acid Potassium Hydroxide
Hydrochloric Acid Phosphoric Acid Sodium Hydroxide
Sulphuric Acid
Storage Precautions:
Store bottles on low shelf areas, or in acid cabinets. Separate bases from acids
Segregate oxidizing acids from organic acids, AND flammable materials. Store bottles on low shelf areas, or in
Segregate acids from bases, AND from active metals such as sodium, potassium, etc. acid cabinets
Segregate acids from chemicals which could generate toxic gases such as sodium cyanide,
iron sulphide, formaldehyde etc.
FLAMMABLES - Fuels are reducing agents
Acetone Cyclohexane Methanol Ethyl Acetate Hexane
Benzene Ethanol Propanol Ethyl Ether Toluene
Isopropyl Alcohol Tetrahydrofuran Gasoline Xylene
Storage Precautions:
Store in approved, labelled flammable storage cabinet(s)
Separate from oxidizing acids and oxidizers.
Keep away from any source of ignition(flames, localized heat or sparks).
Use only "flammable storage" (desparked) refrigerators or freezers.
OXIDIZERS - React violently with organics.
Solids Nitrates, Salts of Liquids
Calcium Hypochlorite Peroxides, Salts of Bromine Nitric Acid
Ferric Chloride Potassium Ferricyanide Hydrogen Perchloric Acid
Iodine Sodium Nitrite Peroxide Chromic Acid
Storage Precautions:
Keep away from flammables, organic solvents, and other combustible materials (i.e. paper, wood, etc.).
Keep away from reducing agents.
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Store in a cool, dry place
PYROPHORIC SUBSTANCES-spontaneously
ignite in air. WATER REACTIVE CHEMICALS
Some finely divided metals React violently with water to yield flammable or toxic gases.
Some organoaluminum compounds (LiAlH4, Al(CH3)3) Solids Magnesium Liquids
Silane Calcium Carbide Potassium Phosphorous
Phosphorus, Yellow Phosphorus, yellow should be stored and cut Lithium Sodium trichloride
under water
Storage Precautions
Avoid exposure to water and air
Store away from flammables
Store in a cool, dry place
HIGHLY TOXICS, CARCINOGENS, REPRODUCTIVE TOXINS
May be hazardous alone or in combination with other chemicals.
Liquids Cyanide solutions Solids Gases
Formaldehyde Ethidium Bromide Cyanide salts Chlorine
Nickel Carbonyl Suphide salts HCl
Mercury Ethidium Bromide Nitric oxide
Fluorine
Storage Precautions
Seal tightly and store in ventilated cabinet Store away from acids and other Store in gas cabinet or other ventilated cabinet.
incompatibles
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