DEPARTMENT OF CHEMISTRY
TEACHING LAB EXPERIMENT RISK ASSESSMENT FORM
This form must be completed jointly by the Lab Officer in charge and the Lecturer in charge. A
hardcopy of the completed form should be kept in a file together with the Project Risk
Assessment.
Name of Lecturer in Charge
Name of Lab Officer in Charge
Module / Expt No.
A/P Jaenicke Stephan
Activity being assessed:
Tan Lay San
CM 2264/Expt 2
Suspension Polymerization
To polymerise polystyrene by suspension polymerization & determine its molecular weight by
viscosity measurements.
Known or expected hazards associated with the activity:
Hazards of reagents, solvents and known reaction products.
State each substance and the approximate amounts to be used/produced.
List of activities involved in this experiment which inevitably entail risks. The following are the
activities being use:
1)
Glass Apparatus. Refer to prepared risk assessment on Use of Glassware
2)
Heating Mantle, Oven. Refer to prepared risk assessment on Use of Laboratory Heating
Equipment
3)
Electricity, Mechanical Stirrer. Refer to prepared risk assessment on Electricity. Refer to
prepared risk assessment on Use of Standard Electrical Equipment
4)
Fume hood. Refer to prepared risk assessment on Use of Fume Hoods
5)
Waste disposal: All organic waste have to be disposed of in the appropriately labelled
waste container placed in a secondary containment housed under the designated fume
hood.
Polyvinyl Alcohol: 0.3g
Combustible solid. May cause respiratory tract, eye and skin irritation.
Calcium Phosphate: 0.06g
May cause respiratory tract, eye and skin irritation.
Benzoyl Peroxide: 0.3g
May catch fire and explode flammable solid. Oxidizer. Contact with other material may cause
fire. Causes respiratory tract, eye and skin irritation. Contains material which causes damage to
the following organs: Respiratory tract, skin, eyes, lens or cornea.
Distilled Styrene: 20g
Flammable liquid and vapor. Harmful if swallowed, inhaled or absorbed through skin.
Causes irritation to skin, eyes and respiratory tract. Affects CNS, liver and reproductive system.
Page 1 of 9
Printed on: 12 February 2016
Mercury:
Mercury is a virulent poison that is readily absorbed through the respiratory tract or through
unbroken skin. It acts as a cumulative poison since only small amounts of the element can be
eliminated at a time. May be fatal if inhaled or swallowed. Causes respiratory tract, eye and skin
irritation. May cause eye and skin burns. Harmful if absorbed through skin. Contains material
which causes damage to the following organs: kidneys, gastrointestinal tract, respiratory tract,
skin, central nervous system, eye, lens or cornea. May be harmful to environment if released in
large amounts. Very toxic to aquatic organisms. The present accepted threshold limit for
Mercury in air is 0.05 mg m-3. (NB. air saturated with mercury vapour at 20°C exceeds the toxic
limit by 100 times).
Nitrogen gas:
A harmful concentration of this gas in the air will be reached very quickly on loss of
containment. On loss of containment this gas can cause suffocation by lowering the oxygen
content of the air in confined areas. See Notes on Reference website.
Toluene: 130mL
Flammable liquid and vapour. Vapor may cause flash fire. May be fatal if swallowed. Harmful if
inhaled. Causes respiratory tract, eye and skin irritation. Causes damage to the following
organs: Kidneys, liver, respiratory tract, skin, central nervous system, eye, lens or cornea.
* Above amount stated are computed for the whole experiment.
Incompatible materials (special precautions):
Polyvinyl Alcohol:
Reactive with oxidizing agents.
Calcium Phosphate:
Not available.
Benzoyl Peroxide:
Reactive with reducing agents, acids, organic materials.
Distilled Styrene:
Vapor is explosive when exposed to heat or flame; reacts with oxygen above 40C (104F) to
form a heat-sensitive explosive peroxide. On exposure to light and air, styrene slowly undergoes
polymerization and oxidation with formation of peroxides. Violent polymerization may be initiated
by alkali metal-graphite composites, butyllithium, dibenzoyl peroxide, azoisobutyronitrile or di-
Page 2 of 9
Printed on: 12 February 2016
tert-butyl peroxide. Styrene reacts violently with chlorosulfonic acid, oleum, sulfuric acid,
chlorine + iron(II)chloride and can react vigorously with oxidizing materials. Dissolves rubber.
Corrosive to copper and copper alloys. Incompatible with peroxides, aluminum chloride, strong
acids, metallic salts, halogens, polymerization catalysts and accelerators.
Conditions to Avoid: Heat, flame, ignition sources, air, light.
Mercury:
Mercury can react with ammonia to produce an explosive solid. It can cause severe corrosion
problems because of its ease in forming amalgams. Reacts violently with dry Bromine.
Nitrogen gas:
Reacts with oxygen and hydrogen on sparking forming nitric oxide and ammonia.
Combines directly with lithium and at red heat with calcium, strontium and barium to form
nitrides. Forms cyanides when heated with carbon in presence of alkalis or barium oxides.
Toluene:
Reactive with oxidizing agents, acids.
The risk of injury and its severity likely to arise from these hazards:
Polyvinyl Alcohol:
Eye Contact: Hazardous in case of eye contact (irritant).
Skin Contact: Hazardous in case of skin contact (irritant). Skin inflammation is characterized by
itching, scaling, reddening, or, occasionally, blistering.
Inhalation: Hazardous in case of inhalation (lung irritant).
Ingestion: Ingestion can cause nausea and vomiting.
Calcium Phosphate:
Eye Contact: Hazardous in case of eye contact (irritant).
Skin Contact: Hazardous in case of skin contact (irritant). Skin inflammation is characterized by
itching, scaling, reddening, or, occasionally, blistering.
Inhalation: Hazardous in case of inhalation (lung irritant).
Ingestion: Ingestion can cause nausea and vomiting.
Benzoyl Peroxide:
Eye Contact: Hazardous in case of eye contact (irritant). Inflammation of the eye is
characterized by redness, watering, and itching.
Skin Contact: Hazardous in case of skin contact (irritant). Skin inflammation is characterized by
itching, scaling, reddening, or, occasionally, blistering.
Inhalation: Hazardous in case of inhalation (lung irritant).
Page 3 of 9
Printed on: 12 February 2016
Ingestion: Ingestion can cause nausea and vomiting.
Distilled Styrene:
Inhalation: Causes irritation to the respiratory tract. Symptoms may include coughing, shortness
of breath. A central nervous system depressant. Higher exposures can cause a build-up of fluid
in the lungs (pulmonary edema), a medical emergency.
Ingestion: May cause irritation to the gastrointestinal tract. Symptoms may include
nausea, vomiting and diarrhea. May cause central nervous system depression. Symptoms may
include lethargy, drowsiness, staggering and sleepiness. May cause possible convulsions and
risk of pulmonary edema.
Skin Contact: Causes irritation to skin. Symptoms include redness, itching, and pain. May
produce blisters. May be absorbed through the skin.
Eye Contact: May cause irritation, redness, pain, and corneal damage. Chronic Exposure:
Repeated exposure may cause nausea, vomiting, appetite loss, a sensation of drunkenness,
general weakness, and functional disorders of the nervous system and liver. May cause
dermatitis. Women may experience ovulation and menstrual disorders. May cause mutagenic
and teratogenic effects. Aggravation of Pre-existing Conditions: Persons with pre-existing skin
disorders, eye problems, liver disease, central nervous system disorders, or impaired
respiratory function may be more susceptible to the effects of the substance.
Mercury:
Chronic effects from continual exposure to small concentrations can cause severe nervous
disturbance, insomnia, loss of memory, irritability and depression. Loosening of teeth, dermatitis
and kidney damage are possible in severe prolonged absorption.
Eye Contact: Hazardous in case of eye contact (corrosive, irritant). May cause burns.
Inflammation of the eye is characterized by redness, watering, and itching.
Skin Contact: Hazardous in case of skin contact (permeator, corrosive, irritant). Skin contact
may produce burns. Skin inflammation is characterized by itching, scaling, reddening, or,
occasionally, blistering.
Inhalation: Extremely hazardous in case of inhalation (lung irritant). May be fatal if inhaled. High
concentration of vapour may cause a metallic taste, nausea, abdominal pain, vomiting,
diarrhoea and headache.
Ingestion: Extremely hazardous in case of ingestion. May be fatal if swallowed.
Nitrogen gas:
Overexposure by inhalation may lead to unconsciousness, weakness, death.
Toluene:
Eye Contact: Hazardous in case of eye contact (irritant). Inflammation of the eye is
Page 4 of 9
Printed on: 12 February 2016
characterized by redness, watering, and itching.
Skin Contact: Hazardous in case of skin contact (irritant). Skin inflammation is characterized by
itching, scaling, reddening, or, occasionally, blistering.
Inhalation: Hazardous in case of inhalation (lung irritant).
Ingestion: Extremely hazardous in case of ingestion. May be fatal if swallowed.
Who is at risk?
Persons handling the chemicals as well as those in the vicinity.
Measure to be taken to reduce the level of risk:
Proper laboratory attire and safety measures must always be used in order to reduce the level
of risk. Wash hands thoroughly after handling. Do not take internally. Eye wash and safety
equipment should be readily available. Styrene should be handled in a fume hood.
Eye protection: Chemical safety goggles.
Hand protection: Gloves.
Please
refer
to
PSSO
Safety
Information
Centre
website
on
safety
measures:
http://www.chemistry.nus.edu.sg/PSSO/index.htm#undergrad
Training prerequisites:
This assessment should be read by everyone who will be using the above mentioned
chemicals.
Please
refer
to
Completed
Risk
Assessment
on
Common
Activities:
http://www.chemistry.nus.edu.sg/PSSO/safety/risk/risk.htm#Common
Level of risk remaining:
The level of risk is low although constant vigilance is necessary to avoid injury.
Emergency action if :
Spill:
Polyvinyl Alcohol:
Small Spill: Use appropriate tools to put the spilled solid in a convenient waste disposal
container.
Large Spill: Stop leak if without risk. Do not touch spilled material. Use water spray to divert
vapor drift. Prevent entry into sinks or drainages. Eliminate all ignition sources. Call for
assistance on disposal.
Calcium Phosphate:
Small Spill: Use appropriate tools to put the spilled solid in a convenient waste disposal
container.
Large Spill: Use appropriate tools to put the material into a convenient waste disposal container.
Page 5 of 9
Printed on: 12 February 2016
Benzoyl Peroxide:
Small Spill: Use appropriate tools to put the spilled solid in a convenient waste disposal
container.
Large Spill: Stop leak if without risk. Do not touch damaged container or spilled material. Do not
clean-up or dispose except under supervision of a specialist. Do not operate radio transmitters
within 100 m of an electric detonator. Avoid contact with a combustible material (wood, paper,
oil, clothing...). Keep substance damp using water spray. Do not touch spilled material. Use
water spray to divert vapor drift. Prevent entry into sinks or drainages. Eliminate all ignition
sources. Call for assistance on disposal.
Styrene:
Ventilate area of leak or spill. Remove all sources of ignition. Keep unnecessary and
unprotected personnel from entering. Contain and recover liquid when possible. Use nonsparking tools and equipment. Collect liquid in an appropriate container or absorb with an inert
material (e. g., vermiculite, dry sand, earth), and place in a chemical waste container. Do not
use combustible materials, such as saw dust. Do not flush into sinks! If a leak or spill has not
ignited, use water spray to disperse the vapors, to protect personnel attempting to stop leak,
and to flush spills away from exposures.
Mercury:
Avoid spreading the mercury contamination by restricting access to the spill area and only use
the designated cleaning tools (e.g. brush, floor mop or dustpan). If mercury has spilled onto a
hot surface (hotplate, mantle, heating element) evacuate the room as high concentrations of
vapour could be present.
Mercury spillages should first be cleaned up as far as practicable by mechanical means, e.g. by
either the special hand operated sucker, or, for larger spills, by using the vacuum trolley
designed for the purpose. Areas that have been affected by fine droplets of mercury (or have
been identified as being contaminated by the Mercury "sniffer" meter) should then be treated
with a slurry composed of equal parts of slaked lime (calcium hydroxide) and flowers of sulphur
mixed with enough water to make a yellow wash. The slurry should normally be left in place for
between 24-48 hours after which it should be cleaned away by careful sweeping with a dustpan
and brush prior to washing with water to remove all traces of the slurry (often several washes).
Before the area may be used again it is essential that a second "sniffer" test be performed to
make sure that the contamination has been removed. Occasionally a second application may
be found to be necessary. Equipment must be decontaminated after use.
Nitrogen gas:
Ventilation (extra personal protection: self-contained breathing apparatus).
Page 6 of 9
Printed on: 12 February 2016
Toluene:
Small Spill: Absorb with an inert material and put the spilled material in an appropriate waste
disposal.
Large Spill: Keep away from heat. Keep away from sources of ignition. Stop leak if without risk.
Absorb with DRY earth, sand or other non-combustible material. Do not get water inside
container. Do not touch spilled material. Use water spray to reduce vapors. Prevent entry sinks
or drainages. Call for assistance on disposal.
Fire:
Polyvinyl Alcohol:
Small Fire: Use DRY chemical powder.
Large Fire: Use water spray, fog or foam. Do not use water jet.
Calcium Phosphate:
Not applicable.
Benzoyl Peroxide:
Small Fire: Use DRY chemical powder.
Large Fire: Use water spray or fog. Do not use water jet. Cool containing vessels with water jet
in order to prevent pressure build-up, autoignition or explosion. Do not fight fire. Evacuate
surrounding areas. Use flooding quantities of water. Avoid contact with organic materials.
Styrene:
Explosion: Sealed containers may rupture when heated. Above the flash point, explosive vaporair mixtures may be formed. Vapors can flow along surfaces to distant ignition source and flash
back. Sensitive to static discharge.
Fire Extinguishing Media: Water spray, dry chemical, alcohol foam, or carbon dioxide. Material
floats on water and may travel back to an ignition source and spread fire. Water spray may be
used to keep fire exposed containers cool. Do not allow water runoff to enter sinks or drainages.
Mercury:
Not applicable.
Nitrogen gas:
Fire extinguishing materials: Non-flammable, inert gas. Use extinguishing media appropriate for
surrounding fire.
Unusual fire and explosion hazards: Nitrogen does not burn; however, containers, when
involved in fire, may rupture or burst in the heat of the fire.
Explosion: In case of fire: keep cylinder cool by spraying with water.
Page 7 of 9
Printed on: 12 February 2016
Toluene:
Flammable in presence of open flames, sparks and static discharge, of shocks, of heat, of
oxidizing materials.
Small Fire: Use DRY chemical powder.
Large Fire: Use water spray or fog. Cool containing vessels with water jet in order to prevent
pressure build-up, autoignition or explosion.
Is the experiment suitable for out-of-hours operation ?
Yes
No
References if any:
Polyvinyl Alcohol: http://www.sciencelab.com/msds.php?msdsId=9927396
Calcium Phosphate: http://www.sciencelab.com/msds.php?msdsId=9927124
Benzoyl Peroxide: http://www.sciencelab.com/msds.php?msdsId=9923063
Styrene: http://www.sciencelab.com/msds.php?msdsId=9925112
Mercury: http://www.sciencelab.com/msds.php?msdsId=9927224
Nitrogen gas: http://www.airgas.com/documents/pdf/001040.pdf
Toluene: http://www.sciencelab.com/msds.php?msdsId=9927301
Signature of Lab Officer in Charge:………………………………………………………………..
Date:…………………………
Signature of Lecturer in Charge:………… ……………………………………..
Date:… ……………………..
Prepared Risks Assessments for standard equipment and operation are with the kind permission of Dr. Ken MacNeil,
School of Chemistry, University of Bristol.
Page 8 of 9
Printed on: 12 February 2016
Activity being assessed:
Note any activity to be used which entail risk (e.g. use of glass vacuum apparatus, high pressures, high
voltage, radiation, high temperatures). Give reference to any special protocols to be followed, and if
appropriate attach copies to the risk assessment form. State any additional precautions taken to minimise
risk.
Known or expected hazards associated with the activity:
FOR EACH CHEMICAL, read the MSDS and note:a) Particular hazards (e.g. highly toxic, carcinogenic, corrosive, flammable, pyrophoric, explosive, volatile,
dust hazard). Note any dangerous combinations of properties (e.g. volatile and toxic).
b) Requirements for safe handling (e.g. fume cupboard, inert atmosphere, low temperature).
c) How to dispose of residuals
 Dispose to drain, with water dilution
 Neutralise, then to drain with suitable dilution
 To flammable liquid waste receptacle
 To non-flammable liquid waste receptacle
 Keep for recovery/recycling
 Keep for special disposal later (e.g. heavy metals)
 Double bag and dispose to dry waste
 Special procedure (specify)
Incompatible materials (special precautions)
Note any dangerously incompatible materials and hazards arising from contact of any reagents and
substances used with common materials such as paper, benches, hoses, etc.
Measures to be taken to reduce the level of risk
Include hazards of previously unknown products.
Location of work – laboratory, open bench, fume cupboard
Level of risk remaining:
Likelihood and consequences of any accident or unforeseen events whilst carrying out the activity. When
this has been done, choose the appropriate procedure:a) Close supervision and/or attendance of trained first-aider needed.
b) Specific approval of supervisor needed.
c) Training is needed prior-to or during the operations specified.
d) Training is complete and only general laboratory competence required.
e) No risk perceived.
Emergency action:
a) Any special requirements to deal with accidental spillage or leakage.
b) What to do in the event of accidental exposure (skin contact, inhalation, etc.).
Page 9 of 9
Printed on: 12 February 2016