Chemical SafetyPriscilla Lee, PhD, RSO, GradIOSH, MHKIOEH

Chemical Safety Manager, Safety Officetel: 2859 2402, email: prislee@hku.hk

Some definitionsHazard:

The potential to cause harmRisk:

The likelihood (probability) of harm actuallyOccurring and the severity of its consequences

Safety is basically concerned with controlling the risks

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Risk assessmentIdentify the hazard

The potential to cause harmIntrinsic properties of the organism/materialThe way in which organism/material will be used in laboratory

Adopt effective measures to control riskReduce likelihood (probability) of harm actuallyOccurring and the severity of its consequences

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Risk assessment in a laboratory settingIdentify the hazard

Slips, Trips, Falls Electric shock Mechanical – from machines etcHeat/Cold – autoclaves, freezers, cryogensPressure (positive and negative) – gas cylindersMusculo-skeletal – manual handling, computer use etcGlassware, sharps/knives, needles Chemicals – fire, burns, toxicity, carcinogenicityBiological agents – infectionRadiation, LASERsNoise e.g. from machinery

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Risk assessment in a laboratory settingAssess the risk:

Varies between laboratoriesApply the controls:

Basic rules, COPs, SOPs, guarding, PPE etc.Laboratory practices and techniquesSafety equipment including PPE (primary barriers)Laboratory facilities (secondary barriers)

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Minimize exposure to chemicals –Hierarchy of control

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Hierarchy of control – Engineering

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Fume cupboard Local exhaust

Glove boxEmergencyventilation

Hierarchy of control – Administrative

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Warning notice

Health and safety information sheet

Hierarchy of control –Personal Protective Equipment

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Why is PPE not favored?Only protects the person using it, all other controls protect others in lab as wellTo be effective must be fitted and used correctly – training and competenceFalse sense of security, particularly if hazardous material can be inhaled eg.

Correctly used powered air purifying respirator (PAPR) provides 40 fold reduction in concentration of inhaled hazard Correctly used fume cupboard or biological safety cabinet provides 100000 fold reduction inconcentration of inhaled hazard 10

Basic laboratory safety rulesObserve the warning signs and symbolsLearn about the Dos and Don’tsAssess risks before starting workKnow the location of and how to use the emergency equipmentKnow the types of personal protective equipment available and use them e.g. labcoats, gloves, goggles and respiratorsAlways be alert to unsafe conditions and actions and call them to the attention of your supervisor. Safety is the responsibility of everyone – don’t expect someone else to sort it outUse equipment only for its designed purpose

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General laboratory safetyLong hair, loose clothing and jewellery should be confinedNO food and/or drink should be kept or consumed in laboratories except for experimental purposesDo not apply make-upNo sandals, flip flops or open-toed shoes

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General laboratory safetyKeep work areas clean and tidyKeep clear of all exits and passagesHandle broken glass and chemical spillage immediatelyHands and forearms should be washed thoroughly with soap or disinfectants before leaving the laboratoryApply good housekeeping practice

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General laboratory safetyPoor housekeeping will lead to:

Hinder escape routeChemical contaminationCutsSlippingTrippingFalling

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What is chemical?Chemical substance is a form of matter that has constant chemical composition and characteristic propertiesIt cannot be separated into components by physical separation methodIt can be solid, liquid, or gasDaily examples: water, table salt, gold, diamondLaboratory examples: Ethanol, hydrochloric acid, liquid nitrogen, etc…

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Some incidents

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A 23-year-old Pomona College graduate was using a plastic syringe to extract from a sealed container a small quantity of t-butyl lithium -- a chemical compound that ignites instantly when exposed to air.As she withdrew the liquid, the syringe came apart in her hands, spewing flaming chemicals, according to a UCLA accident report. A flash fire set her clothing ablaze and spread second and third-degree burns over 43% of her body. Eighteen excruciating days later, Sangji died

Some incidents

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Some incidents

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Some incidents

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Some incidents

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Some incidents

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A bottle of Ethanol was knocked over ---

Handling of chemicalsChemical Handling – Labelling System

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Handling of chemicalsChemicals should be properly labelled and storedInformation of labels should include at least:

Name of ChemicalHazard SymbolDate of Opening / Preparation

Report to your supervisor if chemicals remain after completion of research project

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Handling of chemicalsChemical Handling – Hazard labels

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Handling of chemicalsHazard warning labels – limited information on chemicalsMore detailed document – Materials Safety Data Sheet (MSDS)Source of MSDS: Chemical supplier on delivery, website of chemical suppliers

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Storage of chemicalsDisposal is also considered as storage – storage in waste drumsChemicals should be stored only at designated cabinets – not bench tops, fume cupboards, etc…Check for compatibility before putting/disposing chemicals together

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Compatibility chart - Simplified

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Compatibility chart – US EPA

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Compatibility check

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Compatibility check

Use of chemicalsUnderstand Materials Safety Data Sheet (MSDS)Information on MSDS:

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Chemical identificationHazards identificationFirst-aid measuresFire fighting measuresAccidental release measuresHandling and storagePhysical and chemical properties

Exposure controlPersonal protectionStability and reactivityToxicological informationDisposal informationOthers

Transfer of chemicalsUse goods lift as far as possibleSuitable carrier

Within laboratory – use both hands, one on the neck and the other at the bottom

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Disposal of chemicalsFollow the practice of chemical storageProper storage at designated waste containersProper labellingCompatibility checkRecord on amount of waste generated

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Handling specific chemicals –Flammables

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Solid, liquid, gasFlash point (fp)

The lowest temperature at which a liquid has sufficient vapour pressure to form ignitable mixture with air.The lower the fp, the higher the flammable riskExamples: Diethyl ether (-45 °C), Ethanol (13 °C)

Fire triangle/tetrahedronSource of ignition include matches, burner, hotplate, oven, running motor, sparkSource of fuel such as solventSource of oxygen, ie, atmosphere

Handling specific chemicals –Flammables

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Solvent Flash Points (°C) Boiling Points (°C)Acetone -18 56Acetonitrile 5.6 82Diethyl ether -45 34.6Ethanol 13 78Ethyl acetate -4.4 77.1Hexane -26 68Methanol 11 64.7Tetrahydrofuran -14 66Toluene 4.4 110Xylene 30 138.5

Handling specific chemicals –Flammables

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Work safely with flammables:VentilationIgnitionContainment/ControlExchangeSeparation

Think V I C E S

Handling specific chemicals –Toxics

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Acute vs ChronicLD50 (Lethal Dose50)

The individual dose required to kill 50% of a population of test animalsThe lower the LD50 dose, the more toxic is the chemical

LC50 (Lethal Concentration50)Through inhalation

Occupational Exposure Limit (OEL)Concentration of chemical in air can be exposed without adverse effect

Time-Weighted Average (TWA)Concentration safe for exposure during entire 8-h workday for 5-day working week

Handling specific chemicals –Toxics

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Chemicals LD50 (mice, mg/kg)Sugar 29700Ethanol 14000Vinegar 3310Sodium chloride 3000Malathion 1200Aspirin 1000Caffeine 130DDT 100Arsenic 48Strychine 2Nicotine 1Aflatoxin-B 0.009Dioxin(TCDD) 0.001Botulinum toxin 0.00001

Handling specific chemicals –Oxidizers

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React vigorously with organic solventsAvoid storing with incompatibles such as organic solvents, reducing agents, etc…Examples: Nitric acid, perchloric acid, hydrogen peroxide, chlorates, nitrates, dichromates, permanganates

Handling specific chemicals –Cryogens

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Cryogenic liquids are liquefied gases that are kept in their liquid state at very low temperatures, usually below -150°CExamples: liquid nitrogen, liquid argon, etc…Understand the properties of cryogensHazards: Burns, adhesion, boils and splashes, oxygen deficiency and asphyxiation, etc…Use in a good ventilated areaWear proper personal protective equipment such as goggle, face shield, cryogloves, laboratory gown, etc…

Handling specific chemicals –Hydrofluoric acid

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Choose alternativeUnderstand MSDSAvoid storing/working/disposing with incompatiblesSpecific training for the operation of hydrofluoric acid should be developed, completed and documentedDevelop standard operating procedures (SOP) for each specific workWear proper personal protective equipment with protection against hydrofluoric acid

Handling specific chemicals –Pyrophorics

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Pyrophoric materials are substances that ignite instantly upon exposure to air, moisture in the air, oxygen or waterChoose alternativeUnderstand MSDSExamples: tert-butyllithium, diethylzinc, organoaluminum compounds, palladium catalystsSpecific training should be developed, completed and documented for the operation of pyrophoricsDevelop SOP for each pyrophoric materialWear proper personal protective equipment

Handling specific chemicals –Compressed gas cylinders

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Know the propertiesKept fastened on rigid fixtureUse trolley for transferUse regulator & flow control valveUse flashback arrestor for flammable gasPeriodic leak test & pressure test

Routes of contaminationInhalationIngestionAbsorption/AdsorptionInjection

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Routes of contamination –Protections

Inhalation – use fume cupboard, local exhaustIngestion – no mouth pipetting, no eating/drinking in laboratory, wash hand after leaving laboratoryAbsorption/Adsorption – use protective clothing such as gloves and laboratory gownInjection – take care of sharps and glass

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Oops! Spill! What? How?1. Don’t panic2. Ventilate and evacuate3. Large/Small spill? Large spill call for

emergency help Small spill unsafe or not

trained call for help Small spill safe and trained control the spill

4. Know the chemicals5. Wear PPE (suppose you are

wearing in the lab)6. Act quickly7. Cover/absorb8. Clean46

Oops! Spill! What? How?1. Don’t panic2. Ventilate and evacuate3. Large/Small spill? Large spill call for

emergency help Small spill unsafe or not

trained call for help Small spill safe and trained control the spill

4. Know the chemicals5. Wear PPE (suppose you are

wearing in the lab)6. Act quickly7. Cover/absorb8. Clean47

Emergency response –Chemical in eyes

Wash with copious amount of water for 15 minsKeep your eyelid open with fingersConsult doctor (bring MSDS)

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Emergency response –Chemical in eyes

Structure of tear film not simpleOuter lipid layer partial barrier to materials eg. eye wash getting in to tear layerInner mucin layer can act as a “sponge” for chemical or biological contaminantsNeed to irrigate eye Immediately for 15 minutes to be effectiveBetter to avoid by wearing suitable eye protection in the first place49

Legal requirements

Dangerous goods ordinance and regulationsWaste disposal ordinance and regulationsControl of chemical ordinance and regulationsChemical weapons (conventions) ordinanceHazardous chemicals control ordinance and regulations

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Summary

Identify hazard of the chemicalsMinimize the exposure of chemicals using the hierarchy of controlEmploy good house keeping practiceUtilize safe practice of chemical usage including but not limited to storage, transfer, disposal, etc...Understand the response to emergency situationsUnderstand the legal requirement on the use of chemicals

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Take home message:Safety will work ONLY when

precautions are utilized.

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Thank You!53

Controlled chemicals under the Control of Chemicals Ordinance

Schedule 1:Acetic anhydride, Acetyl chloride, Acetyl bromide

Schedule 2:Ephedrine, Piperidine, Ergotamine, Safrole, Ergometrine, Isosafrole, Pseudoephedrine, Piperonal, Lysergic acid, Anthranilic acid, 1-phenyl-2-propanone, Phenylacetic acid, N-acetylanthranilic acid, 3,4-methylenedioxy-phenyl-2-propanone, Potassium permanganate, Norephedrine

Schedule 3: Export control to some countries54

Chemicals in the Chemical Weapons Convention Ordinance

Schedule 1:These chemicals pose a high risk to the objective and purpose of the Convention and are considered to be highly dangerous. Examples of such chemicals include Sarin, VX, Mustards, Saxitoxin, Ricin etc.

Schedule 2:These chemicals pose a significant risk to the objective and purpose of the Convention.Examples of such chemicals include Amiton, PFIB, BZ etc

Schedule 3:These chemicals pose a risk to the objective and purpose of the Convention. Examples of such chemicals include Triethanolamine, Phosphorus Oxychloride, Thionyl Chloride etc.

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