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ميح ّرلا نمحّرلا الله مسب

Course :

Health Safety & Radiation Protection (RAD453)

Chapter 9 : Risk Assessment & Lab Rules

Omrane KADRI, Ph.D.

[email protected]

Office 2021

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Outline

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Health & Safety at work Five steps for risk assessment General Lab rules a) Chemical Hazards b) Physical Hazards c) Emergency Response

1) Health & Safety at work

Definitions…

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 done • • • • 3

1) Health & Safety at work

Risk Assessment

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 4

1) Health & Safety at work

ACT 1974

“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

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1) Health & Safety at work

Ionising Radiations Regulations 199

“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.” 6

2) Five steps for risk assessment

STEP ONE 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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STEP TWO 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….

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2) Five steps for risk assessment

STEP THREE 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?

• • 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.

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2) Five steps for risk assessment

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

STEP FIVE

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Review your assessment and revise it if necessary

Changes leading to new hazards Periodic review to make sure still fit for purpose 9

3) General Lab Rules

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

Chemical Hazards: flammables

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) – • • 11

3) General Lab Rules

Storage and labeling Flammables are color-coded DOT hazard class 3 red • – Must be stored in a flammable cabinet, away from sources of heat and/or ignition (sparks) – •  Flammable 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.

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3) General Lab Rules

Chemical Hazards: corrosives

• 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.

– 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 Corrosive • • 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 13 • 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 – • • • 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.

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3) General Lab Rules

Chemical Hazards: reactives and oxidizers

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 – – • • • 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.).

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3) General Lab Rules

Chemical Hazards: health hazards

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 • – • 16 Storage: Health hazards are color coded blue – Health hazards should be segregated from other chemicals – 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) • • Poison/toxic – 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) Biohazard

3) General Lab Rules

b) Physical Hazards

Includes (but not limited to): Compressed gases – Electrical equipment – Lasers Thermal hazards – – Radiation – • • • • •

Physical Hazards: compressed gases

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.

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3) General Lab Rules

Physical Hazards: electrical equipment

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: 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.

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3) General Lab Rules

Physical Hazards: thermal hazards

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.

• • – • Be alert to gas leaks along the tubing—these can ignite.

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.

– • Stand back from the burner when lighting the gas.

• Cold Liquid Nitrogen (LN2) • Wear insulated or cryoprotective gloves when accessing LN2.

19 • 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 .

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3) General Lab Rules

Physical Hazards: radiation

Radioisotope use includes both sealed and unsealed sources. Sealed: gas chromatographs, scintillation counters – Unsealed: 3 H, 14 C, 32 P, 125 I – Use of radioactive materials requires prior authorization from the Radiation Safety Officer.

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3) General Lab Rules

c) Procedures in Emergency Situations Damage

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 –

Malfunction of irradiating apparatus

– 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 21 • • • • •

Spillage / aerosol release

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

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Responsible safety officer and RSO to conduct enquiry into cause

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RSO to report

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3) General Lab Rules

Ingestion/inhalation

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

Damage during transport

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 23

Emergency equipment

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 • • • • • • • • 24

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