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Course :حمن بسم الله الّر�

حيم الّر�

Chapter 9 : Risk Assessment & Lab Rules

Omrane KADRI, Ph.D.

okadri@KSU.EDU.SA

Office 2021

Health Safety & Radiation Protection (RAD453)

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1. Health & Safety at work

2. Five steps for risk assessment

3. General Lab rules

a) Chemical Hazards

b) Physical Hazards

c) Emergency Response

Outline

•HAZARD means anything that can cause harm

•RISK is the chance, high or low, that somebody will be harmed by the hazard

•RISK CONTROL involves taking steps to reduce the chance, and/or mitigate the

consequences, of the hazard causing harm

•RISK ASSESSMENT evaluates the risks and decides whether precautions are

adequate or more should be done3

1) Health & Safety at work

Definitions…

What is it?•‘The process of quantifying the probability of a harmful effect to

individuals from certain human activities’

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Why do it?• In most countries, the use of specific materials or the operation of

specific facilities is not allowed unless it can be shown that they do not increase the risk of death or illness above a certain threshold ………………. Legislation!

How do it?• Health & Safety at Work Act 1974• Management of Health & Safety at Work Regulations 1992 (1999)• Ionising Radiations Regulations 1999

1) Health & Safety at work

Risk Assessment

•“It shall be the duty of every employer to ensure, so far as is reasonably practical, the health, safety and welfare at work of all its employees”.

•“It shall be the duty…..persons not in his employment who may be affected thereby are not thereby exposed to risks to their health and

safety”.

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• Every employer shall make a suitable and sufficient assessment of:– risks to health and safety of employees at work– risks to health and safety of persons not in his employment arising

out of his undertaking

ACT 1974

1) Health & Safety at work

•“An employer shall not carry on work with ionising radiation unless he has made an assessment of the radiation hazard to employees or other

persons …. in the event of any reasonably foreseeable accident, occurrence or incident”.

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• “Before a radiation employer commences a new activity, in respect of which no risk assessment has been made by him, he shall make a suitable and sufficient assessment of the risk to any employee and other person…..”

• “All hazards which could cause a radiation accident to be identified and evaluated.”

Ionising Radiations Regulations 199

1) Health & Safety at work

•Hazard identification•Determine the nature of the potential adverse consequences of using radiation•Use the literature!•Don’t forget other hazards associated with the experiment or procedure.

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• Decide who might be harmed and how• Don’t forget …. • Young persons, trainees, new or expectant mothers, cleaners, visitors, contractors,

maintenance workers, members of the public, people who share your workplace….

STEP ONE

STEP TWO

2) Five steps for risk assessment

•Evaluate the risk•Deterministic - dose threshold•Stochastic - ALARA•Exposure assessment - decide how likely it is to cause harm •Risk control – decide on suitable measures

•Even with precautions, is remaining risk high, medium or low?

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• Are all things required in law done? Don’t stop there - is the remaining risk small? If not, how to make it small?

• Think about other possible occurrences - moving sources within the site, new staff, risk of lost sources, human factors.

STEP THREE

2) Five steps for risk assessment

•Record your findings–Only a legal requirement if five or more employees–Minimum record to include–Date, hazard e.g. isotope, activity (MBq)–External / internal, contamination, spills, personal contamination, waste

disposal, lost material etc–Personnel at risk - names–Special Risks (eg 1 team member pregnant, need to work between two

laboratories, control measures)

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• Other risks – e.g. toxic chemical• Assessment must be signed by author

• Review your assessment and revise it if necessary• Changes leading to new hazards• Periodic review to make sure still fit for purpose

STEP FOUR

STEP FIVE

2) Five steps for risk assessment

a) Chemical Hazards

•Chemical hazards fall into 4 main categories–Flammables–Corrosives–Reactive chemicals–Health hazards

•Some chemicals are not generally regarded as hazardous under normal conditions of use

–These include chemicals like sodium chloride, potassium phosphate, sucrose, Tris buffer, glycerol, etc.

–These chemicals are color-coded green, orange, or gray.–These chemicals have a hazard class rating of 2 or less in any category

(flammability, corrosivity, health, reactivity).

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3) General Lab Rules

•Classification:–Class IA: flash point <73 °F, boiling point <100 °F

•Ethyl ether, pentane–Class IB: flash point <73 °F, bp >100 °F

•Acetone, ethanol, methanol, isopropanol, gasoline–Class IC (combustible): flash point 73-100 °F

•Butanol, xylene, turpentine–Class II: flash point 100-140 °F

•Formaldehyde, kerosene•Max. container sizes:

–Glass: 500 mL (IA), 1 L (IB) 1 gal. (1C, II)–Plastic: 1 gal. (IA), 5 gal. (IB, IC, II)–Safety can: 2 gal. (IA), 5 gal. (IB, IC, II)

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Chemical Hazards: flammables

3) General Lab Rules

•Storage and labeling–Flammables are color-coded red

•DOT hazard class 3–Must be stored in a flammable cabinet, away from sources of heat

and/or ignition (sparks)

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Handling Never use an open flame to heat flammable materials.

Use hot water bath, oil bath, heating mantle, etc. Transfer from 5 gal. containers to smaller containers in a fume hood or approved

flammable liquid storage room. Handle only in areas free of ignition sources. Do not transfer Class I flammable liquids in an exit way.

Flammable

3) General Lab Rules

Corrosive

•Definition:–Cause rapid erosion and destruction of building materials or metals–Burn, irritate, or cause destruction to organic tissues such as skin, eyes, lungs, and

stomach–DOT hazard class 8

•Know the location and proper use of spill kits in your lab.–Never use combustible organic materials (such as paper, sawdust, or rags) to clean up

spills.

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Chemical Hazards: corrosives

• Classification, labeling, and storage:– Acids

• Are color-coded• Store liquids and solids in corrosive cabinet, separate from bases• Keep below eye level

- Bases• Are color-coded • Solids may be stored on shelf in lab, away from other chemicals and below eye level• Liquids may be stored in a cabinet, away from acids• Use secondary containment for liquids

3) General Lab Rules

•Handling–Never pour water into acid. Always add the acid to the water. Add acid slowly, with

stirring.–Open bottles of acid slowly and carefully.

•Wear PPE (gloves, goggles/shield, apron) to protect against splashes.–Conduct all work with concentrated acids and bases in a chemical fume hood.–Check location of eyewash and shower prior to beginning work.

•Some acids require special handling:–Example: hydrofluoric acid, picric acid, perchloric acid

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• Wastes– Never mix acid wastes with solvents or metal-containing solutions.– Never dispose of acids or bases down the drain. – Empty bottles should be triple-rinsed with water (collect rinse solutions in waste acid

container) before disposal or reuse of the bottle.

3) General Lab Rules

• Examples:– nitrate salts (Na, K, Ag)– perchloric, nitric, and picric acids– ammonium persulfate

• Storage and handling:– Reactive chemicals are color coded – Store away from incompatible materials– Protect from exposure to conditions that would make the chemical

unstable (air, water, heat, shock, etc.).

•Definition:–Chemicals which will “vigorously polymerize, decompose,

condense, or become self-reactive under conditions of shock, pressure or temperature” (29 CFR 1910.1450(b))

–Chemicals which react violently when exposed to air or water–Oxidizers cause other substances to burn more easily–DOT hazard class 5

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Explosive

Oxidizer

Chemical Hazards: reactives and oxidizers

3) General Lab Rules

•Definition:–Chemical that causes adverse health effects, whether short-term (acute)

or long-term (chronic)–Includes toxins, carcinogens, teratogens, mutagens, poisons, biohazards

(infectious agents)•DOT hazard class 6

–Examples:•Mercury and other metal compounds, ethidium bromide,

formaldehyde•Storage:

–Health hazards are color coded blue–Health hazards should be segregated from other chemicals

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Biohazard

Poison/toxic

• Handling:– Always wear appropriate gloves and other suitable PPE– Know the hazards presented by the chemical you are working with:

• Possible routes of exposure (vary with chemical and procedure)– Include: skin absorption, inhalation, ingestion, injection

• Symptoms of exposure (May be acute and/or delayed) • Possible adverse reactions with other chemicals or conditions (e.g. heat)

Chemical Hazards: health hazards

3) General Lab Rules

b) Physical Hazards•Includes (but not limited to):

–Compressed gases–Electrical equipment–Lasers–Thermal hazards–Radiation

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• Compressed gas cylinders must be restrained in an upright position in the lab.• Caps must be in place when cylinder is not in use.• Make sure regulator and supply lines are in good condition.

– Never use rigid plastic tubing, which can shatter if the pressure limits are exceeded.• When turning on the gas

– Ensure that the flow valve is open (so there will be no pressure in the supply line). Adjust flow valve only after you have opened the regulator.

– Turn your head away from the tank.• Compressed gas safety training should be carried out.

Physical Hazards: compressed gases

3) General Lab Rules

•Always inspect electrical cords prior to use. Do not use if they are cracked or have exposed wiring.

•Never use electrical appliances near water.–Make sure hands are dry when unplugging a cord.

•Do not overload outlets.•Avoid excessive use of extension cords.•Never override the safety features on electrical equipment.

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Physical Hazards: electrical equipment

Physical Hazards: laser

• If you work with lasers in your lab, your supervisor should provide you with specific operating procedures and safety information.

• Laser Safety training is available through dedicated programs.

3) General Lab Rules

•Thermal hazards include both hot and cold objects.•Hot items:

–Use heat-resistant gloves when handling hot items.–Use caution when heating liquids on hot plates.

•Use a stir bar or Boil-Eezers to ensure even heating of the liquids (to prevent superheating and boil-overs)

•Never leave hot plates unattended.•Bunsen burners

•Inspect tubing prior to using the burner. It should not have cracks, and should fit tightly to the burner and to the gas spigot.

–Be alert to gas leaks along the tubing—these can ignite.•Stand back from the burner when lighting the gas.

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• Cold Liquid Nitrogen (LN2)• Wear insulated or cryoprotective gloves when accessing LN2.• Wear face shield or splash goggles to protect face and/or eyes from splashes• Use caution when adding items to LN2. Rapid addition of items can result in splashes to

the face and hands.• Tubes that have been stored in LN2 should be thawed behind a shield.

– Sometimes LN2 leaks into the tube during storage. The nitrogen will rapidly expand upon warming, causing the tube to shatter.

• Liquid Nitrogen trainings should be carried out.

Physical Hazards: thermal hazards

3) General Lab Rules

•Radioisotope use includes both sealed and unsealed sources .–Sealed: gas chromatographs, scintillation counters–Unsealed: 3H, 14C, 32P, 125I

•Use of radioactive materials requires prior authorization from the Radiation Safety Officer.

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Radioactive

Physical Hazards: radiation

3) General Lab Rules

c) Procedures in Emergency Situations

•Initiate personal decontamination•Evacuate•Place barrier at safe distance from source•Identify area as radiation hazard•Report to RSO

–Time, date, place–Names involved/affected–Results of dose assessments–Probable cause of incident

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Damage

– Switch off X ray unit– Put up ‘MUST NOT BE USED’ sign on unit– Disconnect, lock– Responsible safety officer to contact Service/repair representative– RSO to seek accurate assessment of dose; report etc

Malfunction of irradiating apparatus

3) General Lab Rules

•Stop work ; secure cause•Warn others•Isolate and absorb hot spot•Don’t spread•Seal hot spot with bench coat/perspex

/lead•Treat all cleaning materials as radioactive

waste•Check for contamination of people, floor,

bench•Inform supervisor & RSO

•RSO to determine quantity of radioisotope, volume of spillage

and assess exposure dose

•Responsible safety officer and RSO to conduct enquiry into

cause

•RSO to report

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Spillage / aerosol release

3) General Lab Rules

•Get buddy / first aid staff to call Concerned Hospital Poison Centre / ambulance•Warn others•Leave immediately•Secure lab

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• Monitor package for surface contamination• Obtain contact details for distributor• Contact distributor• Replace in emergency container box• Seal, label and arrange for replacement • RSO to report

Ingestion/inhalation

Damage during transport

3) General Lab Rules

•Contamination monitors ( eg Mini monitor E series)•Latex gloves, white coat, perspex glasses•Perspex screens, warning notices•Long handled forceps•Storage container (perspex, lead, concrete)•Equipment manuals•Bags of lead shot, lead sheet•Fire blankets, extinguishers

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3) General Lab Rules

Emergency equipment

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