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 Chuah Gaik Khuan
Activity being assessed:
Ms Toh Soh Lian
CM3193/94
Organic Project
Preparation of Polystyrene by Anionic Polymerization Using Sodium Napthalene
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)
Hotplate/Stirrer, Rotamantle, Oven. Refer to prepared risk assessment on Use of
Laboratory Heating Equipment
3)
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)
Disposal of Syringe with metal needle, Pasteur pipettes, Cannula, Knife. Refer to
prepared risk assessment on Use and Disposal of "Sharps"
6)
Thermometer. Refer to prepared risk assessment on Use, Handling and Clean-Up
Procedures for Mercury.
7)
Quenching of Sodium: It must be done in a fume hood in the absence of water or solvents
as
they
may
result
in
uncontrollable
flame
or
explosion.
Refer
to
http://www.chemistry.nus.edu.sg/PSSO/Safety/SpecHazard.htm
Napthalene: 3.8 gm
Hazardous in case of eye contact (irritant). Inflammation of the eye is characterized by redness,
watering, and itching. Hazardous in case of skin contact (permeator, irritant). Skin inflammation
is characterized by itching, scaling, reddening, or, occasionally, blistering. Hazardous in case of
inhalation (lung irritant). Hazardous in case of ingestion.
Sodium Metal: 0.75 gm
Harmful if swallowed, inhaled or absorbed through skin. Material is extremely destructive to
tissue of the mucous membranes and upper respiratory tract, eyes and skin. Inhalation may be
Page 1 of 12
Printed on: 12 February 2016
fatal as a result of spasm, inflammation and edema of the larynx and bronchi, chemical
pneumonitis and pulmonary edema. Symptoms of exposure may include a burning sensation,
coughing and vomiting.
0.3 M Hydrochloric Acid: ~25 ml
This product is corrosive to the skin, eyes, mucous membranes and respiratory passages. It
may cause immediate or delayed respiratory difficulties. Eye contact may cause irritation of the
conjunctiva or blindness. Ingestion may cause nausea, vomiting, pain, thirst, diarrhea,
circulatory collapse or death.
1% Methyl Red Indicator: dropwise
Effects of Acute Exposure: No known harmful effects.
Tetrahydrofuran (Dried): ~170 ml
Hazardous in case of eye contact (corrosive, irritant). May cause burns. Inflammation of the eye
is characterized by redness, watering, and itching. Hazardous in case of skin contact (irritant).
Skin inflammation is characterized by itching, scaling, reddening, or, occasionally, blistering.
Hazardous in case of inhalation (lung irritant). May be hazardous in case of inhalation (lung
corrosive). May be hazardous in case of ingestion.
Methanol (Anhydrous): ~360 ml
Hazardous in case of eye contact (irritant). Inflammation of the eye is characterized by redness,
watering, and itching. Hazardous in case of skin contact (permeator, irritant). Skin inflammation
is characterized by itching, scaling, reddening, or, occasionally, blistering. Hazardous in case of
inhalation (lung irritant). Extremely hazardous in case of ingestion. May be fatal if swallowed.
Highly flammable & explosive in presence of open flames, sparks and static discharge, of heat,
of oxidizing materials. Flammable & explosive in presence of shocks.
Styrene (Inhibitor free): ~16.9 gm
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.
Acetone: for dry-ice bath
Danger! Extremely flammable liquid & vapor. Vapor may cause flash fire. Harmful if inhaled or
swallowed. Causes eye & skin irritation. Causes damage to the following organs: respiratory
tract, skin, central nervous system, eye, lens or cornea.
Purified Nitrogen
Page 2 of 12
Printed on: 12 February 2016
Nitrogen is colourless, odourless gas. The main health hazard associated with releases of this
gas is asphyxiation, by displacement of oxygen.
Symptoms of over-exposure by route of Exposure: The most significant route of over-exposure
for Nitrogen is by inhalation.
Solid Carbon Dioxide (Dry Ice): ~ 2 pieces
This solid sublimates to gas quickly at standard temperatures and pressures, forming a fog in
air. As a result, the main hazards associated with Carbon Dioxide are related to Carbon Dioxide
gas formation and the cold temperature of the solid and evolved gas.
Contact with solid Carbon Dioxide or cold gas can cause frostbite to skin, eyes, and other
exposed tissue. Carbon Dioxide gas evolved from the sublimation of the solid is an asphyxiant
and a powerful cerebral vasodilator.
*amount stated are computed for the whole experiment.
Incompatible materials (special precautions):
Napthalene
Reactive with oxidizing agents.
Sodium Metal
Forms sodium hydroxide and sodium carbonate and hydrogen gas on exposure to moist air
Incompatibilities: Water, oxygen, halogen, acetylene, aluminum halides, ammonium salts,
oxides, oxidizers, acids, chlorinated organic compounds.
Refer to http://www.chemistry.nus.edu.sg/PSSO/Safety/SpecHazard.htm
0.3 M Hydrochloric Acid
Substances to be avoided: Bases, metals, phosphides, acetylides, borides, carbides, silicides,
vinyl acetate, cyanides, sulphides, formaldehyde, metal oxides, hydroxides, amines,
carbonates, alkali metals, aluminum, corrodes steel.
1% Methyl Red Indicator
Incompatibilities: Reducing agents
Tetrahydrofuran (Dried)
Highly reactive with oxidizing agents. Incompatable with lithium-aluminum alloys.
Methanol (Anhydrous)
Highly reactive with oxidizing agents. Reactive with metals, acids.
Page 3 of 12
Printed on: 12 February 2016
Styrene (Inhibitor free)
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 ditert-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.
Acetone
Extremely reactive or incompatible with oxidizing agents, acids.
Purified Nitrogen
Stability: Normally stable in gaseous state.
Materials with which substance is incompatible: Titanium is the only element that will burn in
Nitrogen. Lithium reacts slowly with Nitrogen at ambient temperatures.
Conditions to avoid: Contact with incompatible materials. Cylinders exposed to high
temperatures or direct flame can rupture or burst.
Solid Carbon Dioxide (Dry Ice)
Materials with which substance is incompatible: Carbon Dioxide will ignite and explode when
heated with powdered aluminum, beryllium, cerium alloys, chromium, magnesium-aluminum
alloys, manganese, thorium, titanium, and zirconium. In the presence of moisture, Carbon
Dioxide will ignite with cesium oxide. Metal acetylides will also ignite and explode on contact
with Carbon Dioxide. Carbon Dioxide will react with alkaline materials to form carbonates and
bicarbonates.
Conditions to avoid: Avoid exposing containers of solid Carbon Dioxide to elevated
temperatures, which could cause rapid loss of product.
The risk of injury and its severity likely to arise from these hazards:
Napthalene
Eye: Hazardous in case of eye contact (irritant). Inflammation of the eye is characterized by
redness, watering, and itching.
Skin: Hazardous in case of skin contact (permeator, irritant). Skin inflammation is characterized
by itching, scaling, reddening, or, occasionally, blistering.
Inhalation: Hazardous in case of inhalation (lung irritant).
Ingestion: Hazardous in case of ingestion.
Page 4 of 12
Printed on: 12 February 2016
Sodium Metal
Skin Contact: Causes burns
Skin Absorption: Harmful
Eye Contact: Causes burns
Inhalation: Harmful
Ingestion: Harmful
0.3 M Hydrochloric Acid
Skin Contact: Irritates
Skin Absorption: No information available
Eye Contact: Irritates
Inhalation: Irritates
Ingestion: Harmful
1% Methyl Red Indicator
No known harmful effects.
Tetrahydrofuran, Acetone & Methanol
Eye: Hazardous in case of eye contact (corrosive, irritant). May cause burns. Inflammation of
the eye is characterized by redness, watering, and itching.
Skin: 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). May be hazardous in case of
inhalation (lung corrosive).
Ingestion: May be hazardous in case of ingestion.
Styrene (Inhibitor free)
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,
Page 5 of 12
Printed on: 12 February 2016
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.
Purified Nitrogen
Inhalation: High concentrations of this gas can cause an oxygen-deficient environment.
Individuals breathing such an atmosphere may experience symptoms which include headaches,
ringing in ears, dizziness, drowsiness, unconsciousness, nausea, vomiting, and depression of
all the senses. Under some circumstances of over-exposure, death may occur. The following
effects associated with various levels of oxygen are as follows:
Concentration symptom of exposure
12-16% Oxygen: Breathing and pulse rate increased, muscular coordination slightly
disturbed.
10-14% Oxygen: Emotional upset, abnormal fatigue, disturbed respiration.
6-10% Oxygen: Nausea and vomiting, collapse or loss of consciousness.
Below 6%: Convulsive movements, possible respiratory collapse, and death.
Health effects or risks from exposure
ACUTE: The most significant hazards associated with this gas are inhalation of oxygen-deficient
atmospheres. Symptoms of oxygen deficiency include respiratory difficulty, ringing in ears,
headaches, shortness of breath, wheezing, headache, dizziness, indigestion, nausea, and, at
high concentrations, unconsciousness or death may occur. The skin of a victim of overexposure may have a blue color.
CHRONIC: There is currently no known adverse health effects associated with chronic
exposure to this gas.
TARGET ORGANS: Respiratory system.
Solid Carbon Dioxide (Dry Ice)
At low concentrations, inhalation of Carbon Dioxide can cause nausea, dizziness, visual
disturbances, shaking, headache, mental confusion, sweating, increased heartbeat, and
elevated blood pressure and respiratory rate. High concentrations of the in air may cause eye
irritation. Contact of the evolved gas with the eyes can cause damage to the retinal ganglion
cells.
Who is at risk?
Persons handling the chemicals and as well as those present 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
Page 6 of 12
Printed on: 12 February 2016
or risk. Wash thoroughly after handling. Do not take internally. Eye wash and safety equipment
should be readily available.
Eye protection: Chemical safety goggles.
Hand protection: Gloves.
Refer to prepared PSSO SAFETY Information Center website:
http://www.chemistry.nus.edu.sg/PSSO/Safety.htm
Styrene should be handled in a fume hood.
Refer to risk assessments on Use of fume hoods.
http://www.chemistry.nus.edu.sg/PSSO/Safety/Safetyequipt.htm
Solid Carbon Dioxide (Dry Ice)
Refer to prepared risk assessments on handling, transportation and storage of liquid nitrogen
and other cryogenic material of Solid Carbon Dioxide.
http://www.chemistry.nus.edu.sg/PSSO/Safety/Risk/cryogenic.htm
Training prerequisites:
This assessment should be read by everyone who will be using the above mentioned
chemicals.
Refer to Completed Risk Assessment forms for 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:
Napthalene
Small Spill & Leak: Use appropriate tools to put the spilled solid in a convenient waste disposal
container.
Large Spill & Leak: Stop leak if without risk. Do not touch spilled material. Use water spray
curtain to divert vapor drift. Prevent entry into sink. Eliminate all ignition sources. Call for
assistance on disposal.
Sodium Metal
Before dealing with spillages take necessary protective measures, inform others to keep at a
safe distance and, for flammable materials, shut off all possible sources of ignition. Cover
liberally with dry soda ash, transfer into dry container and transport to safe, open area. Add, a
little at a time, to a large excess of dry propan-2-ol and leave to stand for at least 24 hours.
Arrange for removal by disposal company.
Page 7 of 12
Printed on: 12 February 2016
0.3 M Hydrochloric Acid
Before dealing with spillages take necessary protective measures, inform others to keep at a
safe distance and, for flammable materials, shut off all possible sources of ignition. Spread soda
ash liberally over the spillage. Transfer to container and arrange removal by disposal company.
Wash site of spillage thoroughly with water.
1% Methyl Red Indicator
Before dealing with spillages take necessary protective measures, inform others to keep at a
safe distance and, for flammable materials, shut off all possible sources of ignition. Mix solids
with wet sand and absorb liquids on inert absorbent and carefully transfer to sealed container.
Arrange for removal by disposal company. Wash site of spillage thoroughly with water and
detergent.
Tetrahydrofuran , Methanol & Acetone
Small Spill & Leak: Dilute with water and mop up, or absorb with an inert dry material and place
in an appropriate waste disposal container.
Large Spill & Leak: Keep away from heat. Keep away from sources of ignition. Stop leak if
without risk. Absorb with DRY sand or other non-combustible material. Do not touch spilled
material. Prevent entry into sink. 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 to sink! If a leak or spill has not
ignited, to protect personnel attempting to stop leak, and to flush spills away from exposures.
Purified Nitrogen
Leak response: Evacuate immediate area. Uncontrolled releases should be responded to by
trained personnel using pre-planned procedures. Proper protective equipment should be used.
In case of a leak, clear the affected area, protect people, and respond with trained personnel.
Locate and seal the source of the leaking gas. Allow the gas, which is lighter than air to
dissipate. If leaking incidentally from the cylinder or its valve, contact your supplier.
Solid Carbon Dioxide (Dry Ice)
Pickup and immediately place solid pieces of dry ice in an appropriate, thermally-insulated,
vented container. Alternatively, allow the solid to sublimate and the gas which is generated to
Page 8 of 12
Printed on: 12 February 2016
dissipate.
Fire:
Napthalene
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.
Sodium Metal
Flammable solid. May ignite on contact with water and moisture evolving in highly flammable
gases. Ignites spontaneously in dry air when heated.
Extinguishing Media: Soda ash, sodium chloride, graphite. DO NOT USE WATER.
0.3 M Hydrochloric Acid & 1% Methyl Red Indicator
Noncombustible.
Tetrahydrofuran, Methanol & Acetone
Extremely flammable in presence of open flames, sparks and static discharge, of shocks, of
heat.
Small Fire: Use DRY chemical powder.
Large Fire: Use alcohol foam, water spray or fog. Cool containing vessels with water jet in order
to prevent pressure build-up, autoignition or explosion.
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 sink.
Purified Nitrogen
Non-flammable, inert gas.
Solid Carbon Dioxide (Dry Ice)
Non-combustible.
Is the experiment suitable for out-of-hours operation?
References if any:
Page 9 of 12
Printed on: 12 February 2016
Yes
No
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=NX0005
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=ACS753
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=B18007
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=R02232
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=TX0278
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=AX1699M
http://www.jtbaker.com/msds/englishhtml/s6986.htm
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=AX0126
http://www4.us.airliquide.com/Reference_Library/Cross_Product_Information/MSDS/10041.pdf
Signature of Lab Officer in Charge:………………………………………………………………..
Date:…………………………
Signature of Lecture 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 10 of 12
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.
Page 11 of 12
Printed on: 12 February 2016
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 12 of 12
Printed on: 12 February 2016