Welcome to the Chemical Safety Training. You can choose to pause anytime during thepresentation and continue at your convenience.

1

This training is intended for all students, staff and the supervisors of those who will beusing chemicals in their research activities, even if the research activities take placeoutside of NUS.

2

Topics on regulatory and NUS requirements, the hazards of chemicals and theconsequences of exposure will be covered. Following that, appropriate control measuresand safe practices on handling chemicals, response to emergency situations will becovered.

There will also be an assessment at the end of this training.

3

Introduction of this training

4

All chemicals can be handled safely, some simply require more care in handling thanothers. Improper handling can cause accidental poisoning and serious accidents such asa fire or explosion. Lives have been lost as a result.

5

Accidents can be prevented through having the right mindset towards safety and health. Therefore in NUS, safety and health is embraced as one of our core values. 

The importance of incorporating safety and health practices in our work is emphasized here by our senior management. 

We would like you to embrace this safety culture, where everyone cares about safety, thinks about safety and behaves safely.

6

To have a better understanding on creating a sustainable safety culture on campus, you may refer to the publications provided. 

7

At the end of this training, you will have an understanding of the various regulatoryrequirements associated with the use of chemicals and the hazards of chemicals

You will also learn how to implement control measures and safe practices in order tohandle chemicals safely and have some knowledge on how to respond in the event of anemergency.

8

We will now go through the regulatory and NUS requirements associated with chemicals.

9

The workplace safety and health (or WSH) Act is applicable to all activities in the lab andworkplaces. It is enforced by the Ministry of Manpower. The WSHA also has specificregulations regarding chemical use and handling. Depending on the type of chemical youuse, they may be governed by different regulators.

10

Risk assessment must be conducted for all laboratory activities. The conduct of a riskassessment is a systematic way of identifying hazards posed to the person whileperforming an activity. Appropriate control measures must be implemented to protectthe person from the hazards identified. We will learn more about risk assessment in thenext slide.

The requirement for medical examinations are specified by the WSH (MedicalExaminations) Regulations.

Chemical suppliers are required by law to provide the safety data sheet (SDS) of thechemicals. We will learn more about SDS later during this training.

Another regulation, the WSH (General provisions) regulations stipulate the limit ofexposure levels to chemicals by staff and students.

11

A sample risk assessment is shown here.

During the risk assessment, you will identify the

1. Hazard of the chemical, describing the potential to cause harm.

2. The possible accident or ill health that exposure can cause.

3. Control measures (such as fume hood, personal protective equipment) to reduceexposure

Control measures must be implemented so that exposure is reduced to as low asreasonably practicable.

Once the hazard, consequence of exposure and control measures are identified, the risklevel can be determined through severity and likelihood ratings, this will be detailed inthe next slide.

12

In this slide, we see a 3 by 3 risk matrix.

The severity and likelihood ratings are assigned with reference to the respective rankingguides.

The numbers shown in the risk matrix are the corresponds to the risk level, which isobtained from the multiplication of the severity and likelihood ratings.

An activity with a risk level below 3 is acceptable and may proceed.

Additional risk control measure should be considered for activities with a risk level of 3or 4.

Activities with risk levels more than 4 must not proceed until additional risk controlmeasures are implemented and the risk level re‐assessed.

You may attend the risk management training conducted by the Office of Safety Healthand Environment (OSHE) to learn how to conduct a risk assessment.

13

In determining the hazard and control measures when working with chemicals, it isimportant you refer to the SDS of the chemical. The SDS is a 16‐section document thatprovides important information of the chemical such as the:

• health and physicochemical hazards,

• safe handling and storage methods,

• emergency response procedures.

The SDS of the chemicals used must be made available to all members in the lab.

14

Different regulators govern the possession and use of various types of chemicals.

We will now go through regulations associated with these chemicals.

15

Singapore Customs controls chemicals that can be weaponised under the ChemicalWeapons (Prohibition) Act.

A total of 43 chemicals or groups of chemicals are regulated.

The list of chemical weapons can be found on Singapore Customs’ website.

These chemicals must not be purchased or used without the approval from OSHE.

16

The Health Sciences Authority regulate the possession, import, export, manufacture and use of controlled drugs (such as morphine, ketamine) under the Misuse of Drugs Act.

Approval is required for possession and use of controlled drugs. A register book must be maintained. All controlled drugs must be kept under lock and key at all times.

Central Narcotics Bureau (CNB) regulate the import and export of controlled equipment, material and substances that are useful for the manufacturing of controlled drugs.

A permit is required for the import of these controlled chemicals.

17

Under the Arms and Explosives Act enforced by Singapore Police Force (SPF), a licence isrequired for the possession of explosive precursors (EP).

Examples of commonly used EP are hydrogen peroxide, nitrates and perchlorates.

The list of EP can be found on SPF’s website.

EP must be locked to prevent unauthorised access.

A register book must be maintain and it shall contain the following information:

•The date of each transfer or supply of EP

•The description, quantity and concentration of the EP

•The name and identification number of the person using the EP

18

The Environmental Protection and Management (Hazardous Substance) Regulations isenforced by NEA. A permit is required to store and/or use any hazardous substance.

Examples of commonly used hazardous substances in the lab are hydrochloric acid andsodium hydroxide.

The full list of hazardous substances can be found on NEA’s website.

A license is required if you choose to import these chemicals from foreign suppliers.

19

Under the Fire Safety (Petroleum and Flammable Materials) Regulations, SCDF regulates:

•diesel and all petroleum (hydrocarbons) with a flash point less than 60°C.

•mixture of chemicals with a flash point of less than 60°C (including wastechemicals)

•flammable materials based on a scheduled list.

Some examples of commonly used flammable materials are metal hydrides andtetrahydrofuran.

The list of regulated chemicals can be found on SCDF’s website.

20

Amount of Petroleum and Flammable Materials stored must be within the MaximumAllowable Quantity (MAQ) and meet the storage requirements as stipulated by SCDF.

Each lab unit can only stored a quantity of flammable liquid equivalent to 1.6 times thatof floor area based on the layout plan approved by SCDF. Each lab unit can only store upto a maximum of 500litres if it is not equipped with a sprinkler system. Those which areprotected by a sprinkler system can store to a maximum of 750litres.

It is important to note that each flammable safety cabinet is restricted to 250 litres offlammable liquid storage.

Also, the maximum quantity allowed on bench top, in fume hoods or any other cupboardthat is NOT a flammable safety cabinet is 10% of the lab’s MAQ.

21

The following formulas are used to calculate the MAQ for types of gases for each lab unitarea.

The MAQ is reduced by half for labs not protected by a sprinkler system.

In addition, cylinders containing different categories of gas must be stored separatelyfrom each other.

22

The Poisons Act is enforced by the Health Sciences Authority (HSA). A licence is requiredfor the import of poisons. Do not import them without prior approval from the FacultySafety and Health Officer and licence applied for.

Examples of commonly used poisons are dimethyl sulfoxide and chloroform.

All poisons must be kept under lock and key in a drawer or cupboard solely reserved fortheir storage.

The poisons list can be found on HSA’s website.

23

Sewerage and Drainage (Trade Effluent) Regulations mandates that no hazardoussubstances can be discharged down the sink or drain. This is enforced by the PublicUtilities Board (PUB).

The Environmental Public Health (Toxic Industrial Waste) Regulations enforced byNational Environment Agency requires hazardous lab wastes to be disposed by licensedwaste collectors.

24

The roles and responsibilities for ensuring chemical safety are mentioned in the safetyand health policy. The legal requirements and best practices for the safe handling ofchemicals are detailed in the chemical safety manual. The policy and manual can beviewed at the respective web‐links provided.

25

Responsibilities of the PI and Lab Supervisors include:

•conducting risk assessment for all activities and ensuring the hazards arecommunicated,

•ensuring all reasonably practicable hazard control measures are implemented,

•ensuring control measures implemented are effective in minimizing the risk,

•ensuring staff and students receive adequate instructions on the safe handling ofchemicals and have undergone the required training, and

•Conducting a chemical inventory check every 6 months.

26

Responsibilities of all chemical users include:

•following all laboratory safety rules, regulations, and standard operatingprocedures,

•reviewing and understanding chemical hazards and hazards of laboratoryprocedures prior to conducting work,

•utilizing appropriate measures to control identified hazards, including theirconsistent and proper use of engineering controls, administrative controls andpersonal protective equipment and

•completing all required health and safety training.

27

Should you need to find out more about the local regulations concerning lab‐basedactivities and the use of chemicals, you may access the NUS legal registry via the web‐link provided.

OSHE has developed a tool, the Online Regulated Material Identifier or ORMI, to assistresearchers to identify the regulatory authority and the associated requirements of eachchemical. Where necessary, ensure that the relevant license has been obtained beforeprocurement of the chemical. The online regulated material identifier can be accessedvia the web‐link provided or from OSHE webpage.

28

The use of chemicals to enhance and improve life is a widespread practice worldwide.But alongside the benefits of these chemicals, there is also the potential for adverseeffects to people or the environment. We will now cover the hazards of chemicals.

29

The Globally Harmonized System or GHS is adopted in workplaces in Singapore. 

GHS is a system for standardising the classification and labelling of chemicals. It is a comprehensive approach to:• Defining health, physical and environmental hazards of chemicals; and• Communicating hazard information, as well as protective measures, on labels and 

Safety Data Sheets (SDS).

30

We will now learn about the various physical hazards associated with the use andstorage of chemicals.

31

One of the physical hazards of chemicals is their explosive nature. It can cause greatdamage if not handled appropriately. Certain chemicals are capable of that causes asudden, almost instantaneous release of pressure, gas, and heat when subjected toshock, pressure or high temperature. There are some chemicals which can becomeunstable and potentially explosive as a result of contamination.

32

The photo shows the result of an explosion of a sealed reaction vessel which injured tworesearchers. The explosion also shattered the glassware around the experimental setupand the sash of the fume cupboard. The conduct of experiment at elevated temperatureand pressure conditions, together with the use of inappropriate equipment resulted inthe accident. A detailed risk assessment conducted prior to the start of this experimentwould have identified high pressure levels as a hazard. Appropriate control measurescould be implemented to prevent the accident.

33

Flammable chemicals are those having a low flash point that can ignite in the presenceof a spark, flame or high temperature. Recall that SCDF classifies chemicals with a flashpoint that is less than 61°C as flammable. The flash point is the lowest temperature atwhich the chemical gives off enough vapour to form an ignitable mixture in air. The flashpoint of a chemical can be found in the SDS. A flash fire or an explosion can occur if thevapour concentration of the chemical in air is within is within its flammable range. Theflammable range is the bounded by the Lower Flammable Limits (LFL) & the UpperFlammable Limits (UFL).

34

Pyrophoric chemicals are those that can ignite spontaneously upon exposure to air ormoisture. Some examples of those commonly used in the labs are metal hydrides,nonmetal hydride, alkyl compounds and silane.

35

Oxidizers are those that promote combustion or the burning of a fire. They must neverbe stored together with flammable chemicals.

Gases kept under pressure present another physical hazard. Damage to the cylinder suchas a broken valve, can trigger a sudden and very rapid loss of containment resulting in anoxygen‐deficient environment or a rocket‐cylinder. Such a cylinder is known to damageand fly through concrete walls and can result in fatalities.

36

Cryogenic liquids have boiling points less than ‐73ºC.

The extremely low temperature is a hazard as skin contact with cryogenic chemicals willcause frost burn.

All cryogenic liquids produce large volumes of gas when they vapourise. One of thecommonly used cryogenic liquid in the lab is liquid nitrogen. 1 litre of liquid nitrogenvapourises into nearly 700 litre of nitrogen gas. An oxygen‐deficient atmosphere canpotentially form when large quantities of liquid nitrogen vapourises.

37

There are also physical hazards associated with the apparatus which are used in thelaboratory.

Many apparatus used in the lab are made of glass. Sharp edges from broken glasswarecan cut the skin and introduce hazardous chemicals into the body if it was used to holdchemicals. Never use your hands to handle broken glass. Use a pair of tongs or broomand dustpan instead. The broken glass must always be disposed into the designated‘sharps’ bin.

Needle‐stick injuries are wounds caused by needles that accidentally puncture the skinand chemicals may be introduced into the body as a result.

As far as possible, use blunt‐tip syringes. Avoid the need to re‐sheath a needle toprevent injuries.

38

We will now move on to the health hazards of chemicals

39

Paracelsus was a physician who founded the disciple of toxicology. He noted that it wasthe dose that makes the chemical a poison or toxic to the body.

The chemical’s potential to cause harm depends on:

• The toxicity of the chemical

• The dose received by the person. The dose depends on the concentration of thechemical, the duration of exposure and how much is absorbed by the body.

• The route or how your body is exposed to the person.

• The frequency or how often the body is exposed

40

Upon exposure to a chemical, The effects of a toxic chemical on the body can be local ‐causing harm at the point of contact or systemic ‐ causing harm at locations distant frominitial point of contact, usually at a target organ.

Acute Health Effect refers to a single severe exposure and rapid absorption of the toxicsubstance. Such effects are usually reversible.

Chronic Health Effect refers to a prolonged or repeated exposure to the toxic substance.Chronic health effects are usually irreversible.

41

Some toxic chemicals cause damage to target organs once they enter the body.

Hematotoxic chemicals cause disorder of the blood and blood forming tissues

Hepatotoxic chemicals cause damage to the liver while neprotoxic chemicals damage thekidneys.

42

Cytotoxic chemicals are those that are toxic to cells. Some cytotoxic chemicals havecarcinogenic, mutagenic or teratogenic effects.

Neurotoxic chemicals are those that can cause damage to the central nervous system.

43

Carcinogenic chemicals are cancer causing.

Mutagenic chemicals can cause changes to genetic material and potentially lead todefective cells.

Exposure to teratogenic chemicals can result in developmental malformations or birthdefects. Staff and students who are pregnant should avoid handling teratogenicchemicals.

44

An allergen or sensitizer is a chemical that causes exposed people to develop an immuneresponse after repeated exposure. The reaction may be as mild as a rash or as serious asan anaphylactic shock.

An irritant is a chemical that can cause tissue damage and inflammation at the point ofcontact.

An asphyxiant displaces oxygen from air or deprive the body of adequate oxygen. Deathcan sometimes result.

45

Corrosive chemicals causes visible destruction or irreversible alterations in living tissueby chemical action at the site of contact. Acids and alkalis are commonly used corrosivechemicals in the lab.

46

There are four main routes through which chemicals can enter the body and cause harm.

They are:

• Dermal or skin absorption

• Inhalation

• Ingestion

• Injection

47

Control measures and safe practices are implemented to prevent exposure to chemicalsby the exposure routes mentioned earlier.

48

Control measures that are effectively implemented can protect the chemical user fromharm by preventing exposure.

Appropriate control measures are determined after the conduct of a risk assessment andthey should be implemented in the following hierarchy:

1. Elimination

2. Substitution

3. Engineering Controls

4. Administrative Controls

5. Personal Protective Equipment

Elimination is the most effective and preferred method of control while the use ofpersonal protective equipment is the least effective control measure to protect thechemical user.

The control of some hazards requires the combined use of more than one controlmeasure to reduce the hazard to the lowest level practicable.

49

Total removal of the hazard and thereby, eliminate the risk of exposure.

Examples of the method of elimination of hazard can implemented are:

• redesigning experimental procedures such that use of a hazardous chemical or adangerous equipment is no longer required

• using lead‐free solder (eliminate risk of exposure to the toxic metal)

50

Substitution is the replacing of the initial hazard with one of a lesser risk

Examples of how substitution can be implemented are:

• using a chemical that is less toxic and has a higher flash point, such using tolueneinstead of benzene

• using a solvent that has a lower vapour pressure (less volatile)

• using nanomaterials that are fixed on a matrix instead of using them in the dry,dispersible state to reduce or prevent potential inhalation hazards.

51

Engineering controls is next in the hierarchy of control measures.

They can be implemented in the form of automation of process, or by isolating thehazard with the use of the glove box and fume hood, machine shields, barricades orsafety interlocks.

52

One of the most commonly used engineering control in NUS is the fume hood. Fumehood is a ventilated enclosure designed to contain and exhaust airborne contaminantssuch as chemical fumes. Before using the fume hood, ensure that the fume hood hasbeen tested and certified. The fume hood must be tested annually by a qualifiedprofessional according to a recognised international standard.

When using the fume hood, the sash must be set at lowest feasible height. The sashposition control the velocity of air that passes through the fume hood. The lower thesash, the better the fume hood can exhaust airborne contaminants and protect the user.Work should be done towards middle of hood. Do not handle chemicals at the edge ofthe fume hood to ensure the fumes are exhausted more effectively. Keep your faceoutside the plane of the hood sash at all times.

53

Take note that fume hoods are not designed for chemical storage.

Clutter not only affects performance of the hood by blocking the air flow.

Clutter also increases the risk of spills and accidents and also increases the risk of spillsand accidents.

Large equipment should be placed on blocks or racks to allow air flow under theequipment.

54

Often, the bottom cabinet of the fume hood is used to store chemicals.

However, not every one can be used to store flammables. Only cabinets that have beenspecially designed and certified can be used for the storage of flammables.

Please take note of the indication for such an approved cabinet.

55

Examples of Administrative controls include

• Safe Work Practices (such as keeping equipment well‐maintained, dailyhousekeeping).

• Developing and implementing standard operating procedures.

• Scheduling maintenance and high exposure operations for times when few workersare present.

56

Chemical labelling is a form of administrative control. The Globally Harmonized System(GHS) adopted by NUS, is a system that defines and classifies the hazards of chemicalproducts, and communicates health and safety information on labels.

Every container must have its contents identified and be labelled with the appropriateGHS pictogram.

57

The following shows the GHS pictograms used to quickly identify the hazards ofchemicals which we have covered earlier.

For example, a container holding a flammable chemical will be labelled with a flame,while oxidizers and peroxides are labelled with a flame over a circle.

58

This slide shows the rest of the GHS pictograms. Take note that one pictogram may beused to represent a few classes of similar hazards. For example chemicals that areclassified as dermal sensitizers and chemicals that are irritants both use the exclamationmark for labelling. The hazard classes shown here are not exhaustive, refer to thechemical safety manual for more information.

59

Personal Protective Equipment is the last resort in the hierarchy of control measures.

It is also the last line of defense in protecting the user from the hazards.

PPE selected must be suited specifically to the task.

They must be inspected prior to each use to ensure they are in the proper condition.

PPE must be worn correctly and must fit properly.

Failure to observe these practices can lead to ineffective protection.

60

Laboratory coats are available in various fabrics and the choice of lab coat depends on the hazards identified in the activity.  A fire‐resistant laboratory coat should be used when handling pyrophoric chemicals. You may refer to the guidelines on the selection of Laboratory Coats for more information. 

61

Gloves is one of the most common PPE used in the lab. Appropriate gloves must beselected to protect the user from the known hazards.

Selection of gloves shall depend on:

•nature of work

•requirements for grip, dexterity, puncture or cut resistance,

•type and concentration of chemicals to be handled.

More information on selecting the appropriate type of gloves can be accessed in theChemical Safety Manual.

No single glove will offer unlimited protection against all hazards

62

Eye protection is another common PPE used in the lab. They must be worn whereverthere is a potential for eye injury.

Safety glasses are different from standard street wear glasses. They have lenses that areimpact resistant and frames that are stronger.

Safety glasses with proper impact and shatter resistance will be marked "Z87" on theframe or lens.

However, they DO NOT offer unlimited protection and and other hazard controlmeasures must also be considered.

63

Safety glasses do not provide adequate protection for the eyes from chemical splashes.They do not seal to the face, resulting in gaps at the top, bottom and sides, wherechemicals may seep through.

Where there is a potential for splashes, use safety goggles or a face shield.

64

Respiratory protection may sometimes be used in the lab.

For respirators to be effective, they must:

• be of the correct type for the situation or hazard;

• fit the person using them;

• be worn 100% of the time when in the hazardous environment; and

• be properly maintained in good working condition.

To ensure the respirator is a good fit to you, you have to be fit tested prior to the use ofthe respirator at work. Please request for fit test via OSHE intranet at OccupationalHealth Clinic or from your respirator supplier.

The most common respirator used in the laboratory is N95 particulate respirator. Pleasetake note that many of these particulate respirators will not provide any protectionagainst chemical vapors. You will still be exposed to the hazards if you use the incorrecttype of respirator.

65

Hazard control measures can be used in combination to reduce the risk to the lowestpracticable level. Is the statement TRUE or FALSE?

The statement is true. The use of a fume hood and appropriate PPE along with theadoption of a safe work procedure is a combination of multiple control measures.

66

Safe practices help to maintain a healthy and safe research environment. We will firstdiscuss about chemical storage.

67

Proper chemical storage minimize the potential of exposure to hazardous materials. Italso prevents flammables from ignition.

Incompatible chemicals must be stored separately to prevent severe consequences inthe event of accidental mixing or spillage.

Do not store chemicals alphabetically unless they have first been separated into theirhazard classes. Never stockpile chemicals in your lab! Quantities should be limited to theamount necessary for the work in progress. Remember to always return the chemicals totheir proper storage facility.

All hazardous chemicals must be placed in a secondary containment.

The capacity of the containment tray must be at least 20% of the total volume ofchemicals stored within it.

68

This chart provides some guidance on chemical storage by their hazard classes.

The ‘X’ indicates that chemicals should not be stored together due to chemicalincompatibility or legislative requirements.

For example, nitric acid, which is an inorganic acid must not be stored together withacetic acid which is an organic acid nor with acetone which is an organic solvent.

The chart is by no means complete, for more information, please refer to the chemicalsafety manual or the SDS of the specific chemical.

69

Here are some examples of undesirable consequences as a result of reactions betweenincompatible chemicals. Hence it is important to properly separate incompatiblechemicals to prevent more severe consequences as a result of spillage.

70

Can you identify what are the hazards in this photo taken during a lab inspection?

First, the flammable gas canister that is in use should be stored away from flammableliquids and all other combustibles. Unused canisters in their original packaging should bestored in the fire safety cabinet.

Second, the 2.5 litre bottle is too big for the shelf. The user has to tilt the bottle before itcan be taken out. This increase the chance of an accident happening and is definitely nota good practice for chemical storage.

Third, all hazardous chemicals must be stored in their appropriate chemical safetycabinet with secondary containment. Flammable chemicals must be stored in aflammable safety cabinet and corrosive chemicals must be stored in a corrosive safetycabinet.

71

Acetic acid is an example of a chemical with dual chemical hazards. It is both corrosiveand flammable.

As its flammability poses a greater hazard, acetic acid must be stored inside a flammablesafety cabinet. By placing it in a fully enclosed secondary container, corrosion of theflammable safety cabinet is prevented.

72

Refrigerators may sometimes be used to store chemicals. However, do take note thatperoxide‐forming and flammable chemicals must NOT be stored in regular, domesticrefrigerators. This is because there are several ignition sources within refrigerators.

Ignition sources within the refrigerator include:

•Switches associated with internal light and thermostat,

•Timers and heating elements in frost‐free refrigerators,

•Compressor motor,

•Power points

These ignition sources can set off a flash fire or an explosion. Only intrinsically‐safe andnon‐sparking refrigerators can be used.

73

These photos show the aftermath/consequences of refrigerator explosions inlaboratories.

Laboratories which purchase intrinsically‐safe and non‐sparking refrigerators shouldrequest the vendor to provide a certificate of proof that the equipment meetinternationally recognized standards.

74

Next is the management of compressed gas cylinders

75

The hazards of compressed gas cylinders are discussed earlier. Unstable placement maycause the cylinder to fall and release the pressurized gas.

To prevent accidents from occurring, cylinders shall be individually strapped against awall or bench or placed in a cylinder stand.

Keep the cylinder valve closed when not in use. Never place cylinders on their side.

Toxic, flammable and corrosive gases should be stored in a gas cabinet. The gas cylindersmust be stored away from heat sources and sources of ignition.

76

Safe practices of chemical transport

77

Chemical transport refers to the moving of chemicals, including chemical waste from onelocation to another.

Improper transportation of chemicals and chemical waste can result in accidents. Avoidtransporting chemicals through crowded areas. This is to minimize exposure to staff andstudents in the event of any chemical spillage. Risk assessments shall be conducted andcontrol measures shall be put in place when transporting chemicals. For example, abreak‐resistant, secondary container can be used to transport a bottle of chemical fromone lab to another within the same building.

78

When transporting large quantities of chemicals, including chemical waste, an approvedchemical trolley should be used.

These trolleys must have safety features such as:

•be made of chemical resistant material

•have compartments to capture and contain chemical spills and

•have lockable wheels to prevent “runaway’ incidents

The complete list of criteria required of chemical trolleys can be obtained from thechemical safety manual.

79

A cargo lift must be used to transport the chemicals.

For buildings where there is no dedicated cargo lift, the passenger lift may be used fortransportation. No one can use the lift during transportation of chemicals.

Adequate warning signage, such as a warning notice on a retractable belt shall be usedduring transportation.

An example of the retractable belt with warning labels is shown.

80

Chemical transfer refers to the dispensing of chemical from one container into another.

Control measures such as conducting the transfer in the fume hood and wearing ofappropriate PPE shall be implemented.

Refer to the SDS for special precautions to be taken when handling shock‐ or impact‐sensitive chemicals.

The transferring of liquid nitrogen and other asphyxiant should be done in a well‐ventilated area.

81

We will now discuss on the safe practices of chemical waste management

82

Proper storage and segregation of incompatible laboratory waste is vital to safety in thelaboratory.

Chemical waste must be stored in appropriate, chemically compatible containers.

Avoid the accumulation of waste. Flammable waste count towards the allowablemaximum storage quantity in the lab specified by the SCDF.

Containers must be closed at all times except when adding waste. All containers must beprovided with a secondary containment to contain leaks and spills.

Containers must not be overfilled, leave at least a 10% head space to allow forexpansion.

83

Container holding hazardous substances must be labelled. The waste container is noexception.

Each waste container must be labelled with the following information:

• The contents of the container and its chemical composition

• Date of waste generated

• The appropriate hazard labels

• Contact information of person who generated the waste

• Special precautions in handling and storage if there are any.

Remember, do not use any abbreviations in the label.

This is a sample waste label that can be obtained from OSHE. You can use the waste labelfrom OSHE, your department or from the waste disposal vendor. Most importantly, allchemical wastes bottles have to be identified and labeled.

84

WSH (medical examinations) Regulations requires people whose work involve thehandling of toxic chemicals such as arsenic and lead to undergo

•a pre‐placement medical examination, and

•subsequent periodic medical examinations

For more information on the requirements of the medical examinations and specifiedchemical hazards, please refer to the Chemical Safety Manual.

85

NUS adopt a risk‐based approach in workplace (industrial hygiene) monitoring. Lab members should conduct a semi‐quantitative risk assessment (SQRA) based on the chemicals used in the lab. The SQRA template can be accessed via the weblink provided. If the SQRA indicate medium or high risk from the chemical hazards, you may request for workplace monitoring from OSHE. 

86

Now we will move on to incident management and emergency response.

87

Accidents can happen due to carelessness or the failure of control measures.

To know what can go wrong in your lab, you must first understand the hazards andpossible consequences through the conduct of a risk assessment of the researchactivities.

Thereafter response plans, mitigating measures and equipment can be determined tomanage possible incidents.

88

In the following slides we will discussed what a person should do when faced withchemical emergencies.

89

In the event of a chemical fire,

If you have been trained in the use of a fire extinguisher, use it to put out the fire from aposition where you can escape. You can also place a fire blanket over the fire to smotherit.

Do not use water on a liquid chemical fire because it will exacerbate the situation andspread the fire.

If the fire is large, do not put yourself at risk. Evacuate the lab and activate the fire alarm.Call for help from a safe location.

90

In case of a minor explosion chemical explosion:

Such as the breaking of a glass beaker, try to contain any release of chemicals.

• Switch off all equipment

• Ventilate the area

• Clean up spilled chemicals

If it is a major explosion, evacuate the lab, activate the fire alarm and call for help from asafe location.

91

If chemical vapours are inhaled:

Close the chemical containers and move away to a well‐ventilated or outdoor area.

Seek medical attention if the symptoms persist.

92

If the eyes or body come into contact with chemicals, use the emergency eyewash or theemergency shower respectively.

Flush the affected area continuously for at least 15 minutes. Medical attention should besought immediately after that.

When using the eyewash, keep the eyes open and rotate the eyeballs in all directions toremove contamination from around the eyes.

Remove contaminated clothing, jewellery and shoes while flushing.

93

In the event of a spill, immediately alert others of the spill and report to your supervisor.

Cordon off the area to prevent people from coming into contact with the spill. If the spillinvolves a flammable chemical, all sources of ignition must be removed.

Contain the spill and proceed to clean up.

Do not attempt to clean up a spill in which you are not trained or equipped for.

If it is a major spill, evacuate the lab and call 6874 1616 and 995 from a safe location.

94

Don personal protective equipment, as appropriate to the hazards and refer to the SafetyData Sheet for information.

When cleaning up a spill, protect floor drains or other means of environmental release.Spill socks/booms and absorbents may be placed around drain, if necessary.

Spill control materials should be distributed over the entire spill area, working from theoutside, circling to the inside. This reduces the chance of splash or spread of the spilledchemicals.

After the spill has been absorbed, use a brush and scoop to dispose absorbent materialsinto an appropriate container. Complete a hazardous waste label, identifying the materialand affix it onto the container. Contact licensed chemical waste collector for disposal.Decontaminate area and equipment with mild detergent and water, where appropriate.

95

We will now touch on emergency equipment which are found commonly in the lab.

This slide shows fire mitigation equipment which are effective in putting out incipientfires.

The class ABC or dry powder fire extinguisher is capable of extinguishing incipient firesinvolving combustible materials, electrical components and flammable liquid chemicals.The Class D fire extinguisher must be used for pyrophoric and metal fires.

A fire blanket which work by stopping the airflow to the fire may also be used to smotheran incipient fire.

96

The spill kit must be made available in all labs handling liquid chemicals. The contents ofthe spill kit includes PPE, absorption materials, neutralizing agents and tools necessaryfor a spill clean up.

97

At no time must access to first‐aid measures of emergency equipment be hindered.

The area around them must be kept clear.

98

All accidents and incidents are required to be reported to the OSHE via the onlineAccident/Incident Reporting System within 24 hours.

99

We have come to the end of this training

100

Remember that as you embark on your research and use chemicals, you can first learnvery important information about them from the safety data sheet. You will also need tobe clear about the regulatory and NUS requirements. Prior to starting your research, youwill be required to conduct a risk assessment. You can attend OSHE’s risk managementtraining to learn about risk management methodology.

In the risk assessment you will identify the hazards associated with the use of chemicalsand the possible consequences of exposure.

To prevent exposure, implement control measures according to the hierarchy of riskcontrols. Also adopt safe practices.

In the event of a chemical incident, do not panic. You have learnt about the basicresponse to emergencies. Report the incident to your supervisor and take appropriateactions to mitigate the situation only if you have been trained to do so.

101

You may now proceed to attempt the online assessment.There are 30 questions and you need to answer at least 24 questions correctly in orderto pass.

You have three attempts.

You will receive the certificate in 7 working days after completing the assessmentsuccessfully.

You may contact us for any questions or comments about this training via the followingemail.

102