Safe working with Hazardous Substances - University of

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Safe working with Hazardous Substances

These slides are the still slides used in the Laboratory Chemical Safety Course. The slides and notes must be read together with the Course Manual.

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Being safe means being in control. Is this person in control?

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Being tidy and having good order is essential to be in control.

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He hadn’t read thesesafety instructions

Safetv

Manu

Don’t wait ‘til its too late!

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Obey the rules!

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The lab. must be left in a safe condition when you leave. If you have difficulty remembering what to do, arrange a reminder.

Only authorised experiments may be left running out of hours and an appropriate notice applied to the door giving contact details. See University Policy [https://www.intranet.bham.ac.uk/university/hsu/documents/hspolicy/hs15/hs8emer.pdf]

https://www.intranet.bham.ac.uk/university/hsu/documents/hspolicy/hs15/hs8emer.pdf

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Elimination (e.g. buying ready-made solution to avoid dispensing powder)

Substitution by something less hazardous and risky

Hierarchy of Control

1 Elimination/substitution

2 Engineering controls - enclosure, guarding

3 Administrative controls

4 Personal protective equipment

5 Information/instruction ↑ F

This is the hierarchy of control that the law requires.1 is most effective.5 is least effective and requires much more effort than 1.

Control is mainly achieved by 1 and 2. 3, 4 and 5 are usually in addition to and in support of 1 and 2.

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Hierarchy of Control

1 Elimination/substitution


3 Administrative controls 4 Personal protective equipment

5 Information/instruction

↑ F

EnclosureEnclose so that hazard cannot contact people or risk of release is eliminated or reduced to acceptable level

Guard so that people cannot make contact with hazard

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Hierarchy of Control1 Elimination/substitution


3 Administrative controls

4 Personal protective equipment

5 Information/instruction

• Safe system of work, to reduce risk to acceptable level• Permits to work• Controlled areas• Written procedures, known and understood• Adequate supervision• Identification of training needs

↑ F

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The labelling regulations have changed over the years and classifications may change as well. If you have old bottles such as these, make sure you have an up to date classification - see HAZDAT

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Material Safety Data Sheets

1 Identification of substance and supplier2 Composition3 Hazards identification4 First aid measures5 Fire fighting measures6 Accidental release measures7 Handling and storage8 Exposure controls/personal protection9 Physical and chemical properties10 Stability and reactivity11 Toxicological information12 Ecological Information13 Waste disposal14 Transport information15 Regulatory information16 Other information

The CHIP Regulations require suppliers to provide a datasheet. However, no one in authority checks datasheets and research has shown that many have errors of missing information.

However, there are circumstances where an MSDS may legitimately say "The toxicological properties of this substance have not been fully investigated." This will change to some extent under the REACH regulations.

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An administrative control - further labelling a peroxidisable substance to show how long it's been kept and when in needs to be tested/discarded - is an important means of dealing with the peroxidisable hazard.

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Warning

Prohibition Signs Mandatory Signs

Safe Condition Signs

Safety Signs Regulations

↑ F

These are the four formats of statutory safety sign. Words are optional but must be in same colour scheme as sign.

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Toxic Corrosive Flammable

Oxidising Explosive

Warning and Information Signs

First Aid

↑ F

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“Must Not” and “Must Do” Signs

No unauthorisedentry

Protective glovesmust be worn

Eye protectionmust be worn

No Smoking Smoking and nakedflames prohibited

↑ F

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Incompatible substances must not be placed together, even temporarily, in case one of the bottles bursts, shattering another to allow the materials to mix.

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Hazardous substance cabinets must not be placed beside the main entrance to the room or an emergency exit.

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Don't abuse hazardous substance cabinets - keep combustible material well away.

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Ducted fume cupboards are usually provided with a ventilated undercupboard to store high volatility and fuming chemicals

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The ventilated undercupboard has corrosion proof linings and a spill tray.

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Smaller bottles may be kept out on the bench. If you decant into your own containers, make sure they're adequately labelled with the major hazard(s), proper name and concentration.

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What will it be? TEATriEthylAmineTriEthanolAmine

Danger! Ambiguous Abreviations

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Local Exhaust Ventilation

↑ F

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Local Exhaust Ventilation

Fume (gases, vapours, particles)

or

through a filter, etc.- for discharge back into workroom

↑ F

is captured- at or near the point of release

into an exhaust system (may include filter/scrubber, etc.)- for external discharge

and removed quickly and completely

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Extract fan

Glove box

FumeCupboard

Room extraction via an extract fan in the wall, or ceiling or by opening a door or wiondow is NOT local exhaust ventilation because the fume has to pass the workers before its removed from the laboratory.

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Local Exhaust Ventilation Systems

Fume CupboardGlove Box

↑ F

A glove box/isolator (also class 3 microbiological safety cabinet) are examples of enclosures which give 100% containment of fume because they are sealed to the room.

A fume cupboard and similar exhaust ventilated enclosures cannotgive 100% containment of fume because they are only partial enclosures - they are open in use and when the opening is closed a small gap still remains by design.

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Minimum Distances - not to scale

Door/window

Fume cupboard

userColumn

Bench

wall

People walking

2m

0.3m

0.3m

1.5m

1.5m

1.5m

0m

A fume cupboard may leak fume out into the lab. if the airflow into it is disturbed.The European Standard for fume cupboards BS EN 14175 specifies minimum distances from room features that may disturb the airflow into a fume cupbord.

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2000mm

Unobstructed area

The area in front of a fume cupboard that must be kept clear of furniture/equipment, etc. should be marked out on the floor.

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Aerodynamic Design- Uniform Airflow

Rear baffle

Bevelled Aperture

By-pass

Air foil

= turbulent

= smooth

This cross section of a fume cupboard shows features essential for good performance

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Fume Cupboard Performance - good

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Fume Cupboard Performance - good

Standing at a fume cupboard disturbs the airflow into it. However, if it is well designed with an adequate face velocity, this disturbance should have minimal impact as shown.

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Fume Cupboard Performance - poor

Slot under hereblocked off

If the slot under the airfoil at the front edge of the work surface is block, turbulance will cause reverse flow out of the fume cupboard

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Fume Cupboard Use - poor

Slot blocked

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Non-aerodynamic Design - Turbulent Airflow

= turbulent

A simple box design will have a non-uniform airflow through the face and turbulance at the edges

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Face Velocity - too low

This fume cupboard is of simple box design and with a low face velocity -gives poor performance.

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Face Velocity - too high

Increasing the face velocity of a simple bow desing only reinforces the turbulance and further reduces performance

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Recirculating Filtration Fume Cupboard Non Aerodynamic Airflow

F I L T E R

Re-circulating filtration fume cupboards exhaust filtered air back into the room. Filters are not 100% efficient and this type of fume cupboard is often of basic box design with a fixed sash opening - front can't be completely closed in an emergency.

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Recirculating Filtration Fume Cupboard Partially Aerodynamic Airflow

F I L T E R

Some models of re-circulating filtration fume cupboard do have aerodynamic features.

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Recirculating filtration fume cupboards are not suitable for:

Recirculating Filtration Fume Cupboard - Limitations

↑ F

• Small molecules such as nitrogen, carbon monoxide or hydrogen because the filterblocks do not absorb these gases

• Boiling off large quantities of solvents or acids

because the filter blocks are intended only to deal with vapours and fumes at ppm concentration, equivalent to solvent evaporation rates of between about 3ml per minutefor small models to 6ml per minute for higher capacity models

• High heat loadings- where internal surfaces are of heat sensitive plastics.

- where previously absorbed substances have low autoignitiontemperatures

• Unventilated work areas

• Any substance for which the installed filters are not specified

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↑ F

• Small molecules such as nitrogen, carbon monoxide or hydrogen because the filterblocks do not absorb these gases


• High heat loadings



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↑ F

• Small molecules such as nitrogen, carbon monoxide or hydrogen


because the filter blocks are intended only to deal with vapours and fumes at ppm concentration, equivalent to solvent evaporation rates of between about 3ml per minutefor small models to 6ml per minute for higher capacity models

• High heat loadings



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↑ F

• Small molecules such as nitrogen, carbon monoxide or hydrogen


• High heat loadings- where internal surfaces are of heat sensitive plastics.

- where previously absorbed substances have low autoignitiontemperatures



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Fume Cupboard

Canopy Hood

Glove Box

↑ F

The canopy hood is also known as a receptor hood - it "receives" fume and once fume is in it the fume is taken into the exhaust system. A canopy hood cannot pull fume into itself - it is not suitable for cold fume as from solvent vapours - it is for hot fume from ovens, furnaces, etc. that is rising on strong convection currents.

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canopyhood

furnace

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This and the next slide show how a canopy hood is not suitable for the cold smoke

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This and the next slide show the correct kind of hood but it is too small ........

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.....a canopy hood should have an area larger/overlapping the area from which the fume may rise.

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Fume Cupboard

Canopy Hood Slot or Captor Hood

Glove Box

↑ F

The Slot or captor hood is like a vacuum cleaner - it is designed to pull fume into itself. However, because the flow of air falls of dramatically away from the hood (the velocity at a distance equal to the diameter of the opening is only 10% of the value at the opening), it must be positioned very close to the source of the fume - within one diameter of the opening

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Velocity contours at a captor hood

The Slot or captor hood is like a vacuum cleaner - it is designed to pull fume into itself. However, because the flow of air falls of dramatically away from the hood (the velocity at a distance equal to the diameter of the opening is only 10% of the value at the opening), it must be positioned very close to the source of the fume - within one diameter of the opening

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Flanging extends velocity contours by upto 25%

Adding a flange to the hood extends the effective distance by upto 25%

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Slot

captor hood

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This shows what happens if the hood is too far from the source of the fume.

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First Aid

First aid means what is done immediately someone is injured, especially where chemical incidents are concerned, first aid must be started immediately - don't wait for the first aider. Call the first aider, when practicable, after the treament has started.

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First Aid - Skin Contact

1 Drench the affected area with clean running water for at least 10 minutes and until no chemical remains in contact with the skin. (Use soap if substance oily/greasy.)

2 Remove contaminated clothing, which is not stuck to the skin, as soon as practicable after commencement of washing.

3 If there is any injury or if skin absorption is suspected obtain medical attention.

This is the generic treatment for most skin contacts.

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1 Flush the eye with clean running water for at least 10 minutes.

2 Obtain medical examination of the affected eye.

First Aid - Eye Contact

This is the treatment for all eye contacts.

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1 Do not make the casualty vomit.

2 Wash out the mouth with water.

3 Give 500 ml of water to drink. (And milk for corrosives)

4 Obtain medical attention.

First Aid - Ingestion

This is the treatment for all ingestions

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1 Remove the casualty from exposure.

2 Rest and keep warm.

3 If the casualty has been seriously affected obtain medical attention.

First Aid - Inhalation

This is the treatment for all inhalations - but, see emergency procedures.

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Hydrofluoric acidSkin contact - calcium gluconate gel

PhenolSkin contact - polyethylene glycol

CyanidesTo hospital Administer oxygen if available

First Aid - Special Cases

There are very few substances for which antidotes are needed - but, where antidotes are needed, they are VITAL, work must not commence without them being to hand. Details in Policy

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Cryogenic liquidsSkin or eye contact - flood the affected area with large quantities of cold

water, followed by the application of cold compresses

Never use dry heatIf the skin is blistered or the eyes are affected, medical

attention must be obtained as soon as possible


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Cold Contact Burns• Remove any clothing that may constrict the blood

circulation to the frozen area. Clothing which has stuck to frozen tissue must not be removed until tissue completely thawed

• Thaw slowly by placing the affected area in a tepid water bath (<45º)

• After thawing frozen tissue cover the affected area with dry sterile dressings

• Obtain medical attention


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Powder Dispensing

Dispensing fine powders requires still air conditions - a fume cupboard is NOT suitable because the high airflow will cause thepowder to spread. The Waysafe enclosures shown here are for handling fine powders. The enclosures are equipped with a small fan exhausting through particle filters in oder to keep them under a slight negative air pressure and prevent dust leaking out.

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Respiratory Protective Equipment

• Filter respirator– contaminated air breathed through a filter

∗ filter must be matched to contaminantNOT suitable for oxygen deficient atmospheres

• Breathing Apparatus– oxygen, compressed air or air from clean source

supplied to masksuitable for oxygen deficient atmospheres

Both types may use same style of facepiece

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will not provide automatic protectionmust be adequate and suitable for the purpose- capable of protection for the specified hazard

filter-type cannot protect against oxygen deficiency filters must match contaminant

- able to reduce exposure to acceptable levelsufficient filter performance

sufficient leak-tightness - all respirators leak!- tight-fit masks require facepiece fit-testing,

to match size and shape to wearer!

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For each individual user:• A variety of shapes and sizes from various models• Personalised fit-test report - keep for five years• Repeat fit-testing if wearer:

− loses or gains weight− undergoes substantial dental work− develops any facial changes around faceseal area

Facepiece fit-testing

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Facepiece stylesTight-fitting

Filtering facepiece Full-face mask

Powered hood/blouse

Ventilated helmetVentilated visor

Loose-fitting

Half-mask

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Eye Protection

Basic Use

Large dust (4)Liquid Splashes (3)

Low Energy Impact (-F)Med Energy impact (-B)

Liquid Droplets (3)

Gas & fine dust Dust (5)Molten metal, hot solids (9)

OKOK

OK

OK

OKOK

OK

OKOK

OK

OK

OKOK

OK

BS EN166 Field of UseGoggles Face

ShieldSafety

Spectacles

High Energy impact (-A) OK

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How NOT top hold a bottle

Hazardous Contamination

Even dilute perchloric acid spills may be dangerous

Perchloric acid makes wood highly flammable - readily ignited.

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Use spill trays to prevent bench contamination.

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Use spill tray - its easier to decontaminate the tray than the room!

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Glove Resistance

E = Excellent X = Do not useG = Good F = Fair

PE/EVOH/PE

EEEEGEEEEEE

Acetic acidSulphuric acidNitric acidHydrochloric acidHydrofluoric acidSodium hydroxideAmmonium hydroxideXyleneChloroformDioxanPetroleum ether

Natural Rubber

EGXGGEEXFFF

Neoprene

EGXGGGEFFXG

Nitrile

EFXGGGEGGXE

PVC

EEFGGGEGFXG

Generic peformance for materials, actual perfomance also dependson manufacturer, thickness and model of glove

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Carrying Hazardous Substances

How NOT to hold a bottle

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Spillage

Control hazards- eliminate sources of ignition- stop spread of liquid

Take precautions- evacuate- use personal protective equipment

Clean up/Decontaminate- scoop up solids, mop up liquids- ventilate

Generic procedure, actual actions depend on substances involved and scale of incident - see Policy

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Dangerous Traditional Glass Cleaners

Nitric Acid / Alcohol -also a rocket fuel!

Hydrofluoric Acid -Victorian glass cleaner

Don't use dangerous materials for trivial purposes - another example is chromic acid solution which is carcinogenic and reactive.

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INSTRUCTIONSPierce can

and stand inboiling water

Say what you mean

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Dangerous Economy of Scale

Its the dose (exposure) that matters, a lot of a low hazard substance can be lethal.

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What is Waste?

For the protection of the environment,

Waste is:

Any substance or object which the holder discards or intends to, or is required to discard

All waste is controlled by law, even non-hazardous waste

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Hazardous Waste

Any controlled waste which is:

• Explosive• Oxidising• Highly Flammable• Toxic• Harmful• Corrosive• Irritant• Dangerous to the Environment

subject to concentration limits

Further regulations apply to hazardous waste.

NB concentration limits are different to those for bottle labelling.

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Hazardous waste MUST NOT be disposed of:

• in the ordinary waste bins• down the sink

Organic solvents MUST BE collected separately: as Halogenated and Non-halogenated AND

removed by specialist contractor

Disposal of Hazardous Waste

Other solids and liquids MUST BE treated AND/OR removed by specialist contractor

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Discharge to Sewers -Maximum Levels

pHSulphideSulphateAmmoniaOrganic solventsCyanideAvailable SO2

Available chlorineFormaldehydeSoluble Cr, Cu, Ni, Cd, Pb, SbTotal Soluble/Insoluble

6-1110ppm (0.001%)

1500ppm (0.15%)100ppm (0.01%)

010ppm (0.001%)10ppm (0.001%)

100ppm (0.01%)20ppm (0.002%)10ppm (0.001%)30ppm (0.003%)

These are the limits that must be observed for the University's waste water - they are very low. Some substances are prohibited - see Policy

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Effluent Disposal

A lot of dilution is needed for sink waste

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Treatment of Chemical Waste

• Neutralisatione.g. Acids and alkalis

• Decompositione.g. hydrolysis of acid chlorides

• Chemical Modificatione.g. oxidation of cyanides

• Stabilisatione.g. precipitaion of heavy metals

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Safe working with Hazardous Substances - University of