B1 PRINCIPLES OF TOXICOLOGY & EPIDEMIOLOGY

Question 1

Give the meaning of the classification “Carcinogenic”

Answer 1

Carcinogenic
Can induce the growth of malignant tumours.
Cancer causing

Question 2

The Legal Framework

What are the European Regulations that control the supply and use of hazardous substances in the UK

Answer 2

What are the European Regulations that control the supply and use of hazardous substances in the UK

1) Registration, Evaluation, Authorisation and restriction of Chemicals (REACH) Regulation EC 1907/2008 and,
2) Classification, Labelling and Packaging of substances, and mixtures (CLP) Regulation EC1272/2008 (due jun2 2015)

Question 3

The Legal Framework

What are the UK Regulations

Answer 3

What are the UK Regulations
-Chemical (Hazard, information and packaging for supply) regulation 2009 (CHIP4) (disappearing CLP replaces it)

• Control of substances hazardous to health regulations 2002 as amended (COSHH)
• Control of lead at work regulations 2002 (CLAW)
• Control of asbestos regulations 2012 (CAR)

Question 4

What is reach designed to do?

Answer 4

What is reach designed to do?

1) Improve information in the supply chain - many substances are data poor and this can lead to inadequate risk assessments
2) Promote better risk management
3) Facilitate compliance with COSHH
4) Encourage the use of safer alternatives for CMR substances
5) Allow the free movement of substances on the EU market
6) Question the need for animal testing
7) Lead to improvements in occupational health

Question 5

What does CMR stand for

Answer 5

What does CMR stand for
CMR's are high risk substances
Carcinogens
Mutagens
Toxic for reproduction

Question 6

What is reach concerned about

Answer 6

What is reach concerned about: Reach is concerned about substances, whether on their own or in preparations or articles

Example
Substance: Copper & Zinc
Preparation: Brass , alloy of copper + zinc
Article:Tap

Question 7

Substances not covered by Reach are:

Answer 7

Substances not covered by Reach are:

• -Radioactive (ionising regs)
• -dangerous goods in transit ( road traffic legislation)
• -in customs
• -non-isolated intermediates eg metal ingots to be made –into other articles
• -waste (environmental laws)

Question 8

How does reach work

Answer 8

How does reach work

1) Registration: producers or importers of chemical in volumes of 1 tonne or more must register submitting information on Properties, Uses and Safe ways of handling them.
2) Evaluation through public authorities (HSE) completeness check, compliance check, dossier evaluations and substance evaluation
3) Authorisation - use specific authorisation will be required for chemicals that cause - Cancer, mutations, problems with reproduction or those that accumulate in human bodies and the environment. Authorisation will only be granted once companies can show that the risks are adequately controlled

Question 9

What are the restrictions to reach

Answer 9

What are the restrictions to reach
Substances of very high concern (SVHC) will be taken out of use altogether and some will have to be specifically ‘authorised for use’

Question 10

ECHS means

Answer 10

ECHS means the European Chemicals Agency

Question 11

DNEL means

Answer 11

DNEL stands for derived no effect level.The DNEL represents a level of exposure above which humans should be exposed.

Question 12

Chemical Safety assessment is

Answer 12

Chemical Safety assessment is part of the REACH registration package and is an assessment of a substances hazards, uses and recommended risk reduction methods.

Question 13

Bioaccumulation means

Answer 13

Bioaccumulation refers to the accumulation of substances, such as pesticides, or other organic chemicals in an organism = build up of lead in bone marrow

Question 14

PNEC means

Answer 14

PNEC stands for ‘predicted no effect concentration’ the PNEC represents the concentration of a chemical in any environmental compartment below which unacceptable effects will most likely not occur

Question 15

SVHC means

Answer 15

SVHC Substances of very high concern are substances that have hazards with serious consequences for human health or the environment, E.g they have the potential to cause cancer, or they remain in the environment for a long time with their amounts in animals gradually building up.

Question 16

CoSHH Philosophy

Answer 16

CoSHH Philosophy

1) all obligations on individual employer
2) covers all work activities with all hazardous substances at that site, including process derived substances (dust, fume)
3) tends to be task/process driven
4) risk management measures more likely to be site specific

Question 17

Reach philosophy

Answer 17

Reach philosophy

1) main obligations on manufacturer/importer (though also on supplier and downstream user)
2) covers manufacture of a substances and all identified users across the EU > 10 tonnes /year
3) substance driven
4) risk management measures more likely to be broadly based

Question 18

Intention of CLP regulation

Answer 18

Intention of CLP regulation
Similar to CHIP- substances and mixtures that are placed on the market should be classified, labelled and packaged appropriately.

The aim of the classification of chemicals is to reflect the type and severity of the intrinsic hazards of a substance or mixture

CLP regulation also

• included the hazard class - the nature of the hazard i.e physical, health or environmental hazard
• includes the hazard category - the severity of the hazard within each hazard class (1 = highest severity
• introduces signal words - referring to the relative safety of the hazard e.g “warning” or “danger”
• introduced newly designed hazard symbols
• introduces new labelling phrases known as hazard statements and precautionary statements
• introduces new provisions for a classification and labelling inventory
• maintains the list of harmonised classifications

Question 19

CHIP 4 Regulations 2009

Answer 19

CHIP 4 Regulations 2009 sets out the transitional arrangements for the implementation for CLP within the UK requiring that
substances are
1)identified and classified to decide whether the chemical is dangerous to supply
2)information was provided e.g labelling, safety and health phrases, symbol and safety data sheets and
3)safety packaged

Question 20

Classification is the process of:

Answer 20

Classification is the process of:

1) deciding what kind of hazard the chemical has
2) explaining the hazard by assigning a simple sentence that describes it ( known as a risk phrase or r-phase

Question 21

COSHH defines a substances hazardous to health as one which:

Answer 21

COSHH defines a substances hazardous to health as one which:
1) is listed in the approves supply list (ASL) as dangerous for supply within the meaning of the CHIP regulations and for which an indication of danger specified for the substance is very toxic, toxic, harmful, corrosive or irritant
2) the health and safety executive has approved a workplace exposure limit (WEL) inhalation only
3) is a biological agent (anthrax, Ebola, Hep, Viles disease
4) is dust present at a concentration in air equal to or greater than:
10mg/m3 as a time weighted average over and 8 hour period of INHALABLE dust
4mg/m3 as a time weighted average over an 8 hour period of RESPIRABLE dust and or
5) because of its chemical or toxicological properties and the way it is used or it present at the workplace crease a risk to health (anything else cosmetics pesticides)

Question 22

Respirable means

Answer 22

Respirable fraction – the mass fraction of inhaled particles penetrating to the unciliated airways

‘Respirable dust’ is dust of such a size that it is able to enter the lower levels of the lung during normal breathing (approx. 0.5 to 7.0 micron). Respirable dust is
often in the form of long particles with sharp edges which cause scarring of the lung lining (fibrosis). This limits the capacity of the lungs and, therefore, the
amount of air in the lungs.

Respirable dust approximates to the fraction that penetrates to the gas exchange region of the lung.

4mg/m3, as a time-weighted average over an 9-hour period, of respirable dust

Question 23

Inhalable means

Answer 23

Substance that can be inhaled
‘Inhalable dust’ (sometimes referred to as total inhalable dust) is the total dust that will enter the nose and mouth and lungs during breathing.

Inhalable fraction – the mass fraction of total airborne particles which is inhaled through the nose and mouth.

Inhalable dust approximates to the fraction of airborne material that enters the nose and mouth during breathing and is therefore available for deposition in the respiratory tract.

10 mg/m3, as a time-weighted average over an 8-hour period, of inhalable dust,

Question 24

CoSHH duties

Answer 24

6 - assessment
7 - prevention or control of exposure
8 - use of control measures
9 - maintenance, examination and test of control measures
10 - monitoring exposure at workplace
11 - health surveillance
12 - information, training
13 - arrangements to deal with accidents, incidents and emergencies

Question 25

Outline what is required for a CoSHH risk assessment

Answer 25

CoSHH risk assessment
the assessment should over all hazardous substances, including those:
-brought into the workplace and handled stored and used for processing
-produces or give off e.eg
As fumes
by a process or an activity or as a result of an accident or incident
-used for, or arising from maintenance, cleaning and repair work
-produced at the end of any process, e.g wastes, residues, scrap
-produced from activities carried out by another employers activities

Question 26

Outline the information do you need to gather for each hazardous substance

Answer 26

Outline the information do you need to gather for each hazardous substance:
-the form of the substance e.g solid, liquid, gas
-nature of the substance e.g raw material, by product, waste
-the hazardous properties presented by the substance e.g irritant, corrosive, toxic
-the effect of mixtures of chemicals e.g antagonistic effects
-quantity to be used or created
-concentration of hazardous substance
WEL, if assigned
-nature of work e.g painting or spraying
-duration and frequency of the exposure
-activities where exposure is likely to be unusually high e.g maintenance of chemical containers, accidental release
-routes of entry into the human body, especially what may be inhaled e.g volatile liquids, dusts, fibres
-the number of people exposed and individual susceptibilities
-results from health surveillance and exposure monitoring
-effectiveness of the control measures

Question 27

Suitable and sufficient CoSHH assessment

must be comprehensive and take into account those substances which are:

Answer 27

Suitable and sufficient CoSHH assessment
must be comprehensive and take into account those substances which are:
*brought into the workplace and handled, stored and used for processing
*produced or given off e.g as fumes, vapour dust. By a process or an activity or as a result od an accident or incident
*used for, or arise from maintenance cleaning and repair work
*produced at the end of any process e.g wastes, residues, scrap
*produced from activities carried out by another employers employees in the vicinity

Suitable and sufficient means:
Suitable: are measures Relevant, appropriate and other synonyms

Sufficient: Reasonable - do they take into account best practice and advice as well as Approved Codes of Practice/Codes of Practice/Guidance and of course legislative requirements?

Question 28

The assessment of the risks created by work activities should also include consideration of:

Apart from assessing the risks created by work activities outline what else should be considered:

Answer 28

The assessment of the risks created by work activities should also include consideration of:

• The properties I.e. physical, chemical or biological of the substances and the effects they could have on the body
• Where those substances are likely to be present and in what form eg dust, vapour, mist, fume etc and whether they are used or produced and in what amounts and how often
• the ways in which and the extent to which any groups of people could be exposed, including maintenance workers who may work in circumstance where exposure is foreseeably higher than normal: office staff, night cleaners, security guards, members of the public such as visitors, patients etc taking into account the type od work and process and any reasonably foreseeable deterioration in or failure of any control measure provided
• the need to protect particular groups of employees who may ne at an increased risk eg inexperience’s trainees and young people aged under 18, pregnant workers, disabled workers, and nay employees known to be susceptible to certain illnesses such as dermatitis, asthma or other diseases which may be caused by exposure to hazardous substances
• an estimate of exposure, taking into account any information that may be available about
• -the concentration likely to be produced by the work concerned
• -the effort needed to do the work and how this may affect the rate and volume of air employees breathe
• -the effect of any engineering control measures and systems of work currently used for controlling potential exposure. to complete the assessment, it may ne necessary to carry out atmospheric sampling and measurement to determine exposure particularly where operations are complex or specialised and the substances involved have an occupation exposure limit
• • how the estimate of exposure compares with any existing, valid or standards which represent adequate control eg workplace exposure limit (WEL) or biological monitoring guidance value (BMGV

Question 29

What is a target organ?

Answer 29

What is a target organ?

• -Respiratory system
• -Circulation system
• -Digestive system
• -The eyes
• -The nervous system- Central (brain and spinal cord)peripheral (arms feet) and autonomic (breathing)
• -The Skin - epidermins, dermis, subcutis

Question 30

Target organs most effected

Answer 30

Target organs most effected:

Central nervous system if the target organ of toxicity most frequently involved in systemic effects

Question 31

Skin

Answer 31

The skin is the largest organ in the human body, 1.5-2 m2 in area. It provides a protective cover to the body but can fail if the load is overwhelming. A number of
substances can penetrate healthy intact skin and enter the blood circulation.
Phenol is a substance that may even result in death after exposure and penetration through the skin.
The vast majority of work-related skin diseases are contact eczema, irritation and inflammation of the skin. This condition can be either a non-allergic or allergic
reaction to exposure to chemical substances. Several colorants and dyes, metals e.g. nickel and its salts, chromium and cobalt salts and organomercuric
compounds, monomers of a number of acrylates and rubber additives are examples of common contact sensitizers. In practice also circumstances, such as
humidity and heat, influence the formation chemical skin injury.

Question 32

Lung

Answer 32

The lung is the major route through which toxic substances enter the body in the workplace. It is also the first organ to be affected by dusts, metal fumes, solvent
vapours and corrosive gases. Allergic reactions may be caused by substances such as cotton dust, TDI (toluene diisocyanate, used in the manufacture of polyurethane plastics or spray painting of cars), and MIC (methyl isocyanate, used in production of carbaryl insecticide). In a disastrous chemical accident in Bhopal, India, in 1984, more than 2000 people died from exposure to MIC.
Allergic reactions may result also from exposure to bacteria or fungi: this is the case in allergies from handling stocked hay (`farmer’s lung’) or dried sugar cane. When dust particles of a certain size of some substances are inhaled the lungs are unable to remove them. The particles become embedded in the lungs causing a condition called pneumoconiosis. Pneumoconiosis is a specific problem for workers
exposed to the dust of silica (quartz) and asbestos, and is the most common nonmalignant occupational lung disease throughout the world. Other substances, such as formaldehyde, sulphur dioxide, nitrogen oxides and acid mists, may cause irritation and reduce the breathing capacity.

Question 33

Nervous system

Answer 33

The nervous system is sensitive to the hazardous effects of organic solvents.
Some metals affect the nervous system, especially heavy metals such as lead, mercury and manganese. Organophosphate insecticides such as malathion and
parathion interfere severely with information transmission (chemical neurotransmitter function) in the nervous system, leading to weakness, paralysis and sometimes death.

Question 34

blood

Answer 34

The blood circulation is a target for the adverse effects of solvents. Blood cells are mainly produced in the bone marrow. Benzene affects the bone marrow; the first sign is mutation in the blood cells called lymphocytes. To study mutation, lymphocytes are cultured in the laboratory to observe specific types of cellular changes.
Lead, in the form of the metal or its compounds, is another classic example of a chemical that may cause blood problems. Lead in the blood may inhibit certain
enzyme activities involved in the production of haemoglobin in red blood cells.
Chronic lead poisoning may result in a reduced ability of the blood to distribute oxygen throughout the body, a condition known as anaemia.

Question 35

Liver

Answer 35

The liver the largest of the internal organs of the body, has several important functions. It is a purification plant which breaks down unwanted substances in the
blood. The liver has a considerable reserve capacity; symptoms of liver disorder appear only in serious diseases. Solvents such as carbon tetrachloride, chloroform and vinyl chloride, as well as alcohol, are hazardous to the liver.

Question 36

Kidneys

Answer 36

The kidneys are part of the body’s urinary system. They have the task of excreting waste products that the blood has transported from various organs of the body, of
keeping the fluids in balance and of ensuring that they contain an adequate blend of necessary salts. They also maintain the acidity of the blood at a constant level.
Solvents may irritate and impair kidney function. The most hazardous to the kidneys is carbon tetrachloride. Turpentine in large quantities is also harmful to the
kidneys: `painter’s kidney’ is a known condition related to occupational exposure.
Other well-known kidney-damaging substances are lead and cadmium.

Question 37

Substances can cause both……….

Answer 37

Substances can cause both local and systemic effects

LOCAL effects occur when the SITE OF THE DAMAGE is at the point of contact with the substance eg corrosive burn - stomach irritation and stomach upset (to much alcohol)

SYSTEMIC effects occur when the site of damage is at a point other than the point of contact, such as a target organ e.g the effect of inhaled lead fumes on the brain

an increase in the blood alcohol level which can cause damage to brain cells (to much alcohol)

Question 38

Acute effects

Answer 38

Acute effects:
immediate obvious response
seconds, minutes or hours of exposure
can be delayed
often temporary
can be permanent or fatal

CO2 - alcohol
nausea, headache or vomiting a worker might experience after using a solvent to clean auto parts

formaldehyde - headaches eye irritation

drunkenness, dehydration headache and a hangover (to much alcohol)

Question 39

Chronic effects

Answer 39

Chronic effects:
appear a long time after exposure occurred
long latency period
often irreversible
occurs in one of two ways
bioaccumulation
bedown products

asbestos
formaldehyde - cancer

permanent liver damage (cirrhosis) which can have a latency period of many years (to much alcohol)

Question 40

What are the Routes of entry for a chemical?

Answer 40

What are the Routes of entry for a chemical?

• Inhalation - WELS - once breathes in it can attack the nose, throat and lungs
• skin contact (absorption) - some damage the skin while others pass through it - dipping hands in it, splashing, airborne dust, contaminated surfaces
• ingestion - by smoking eating or drinking biting nails without washing first
• exposure to the eyes - vapour , gas or dust irritate the eyes or acid in the eyes
• ears - earplugs contaminated = dermatitis of the ear
• injection (skin puncture) - needle stick injuries, HIV, drugs

Question 41

What factors determine the toxic effect of a chemical?

Answer 41

What factors determine the toxic effect of a chemical?

1) the route of entry- the way the chemical gets in to the body
2) the physical form of the chemical (solid, dust, liquid, vapour, gas, mist

Question 42

What are the physical forms of a chemical?

Answer 42

What are the physical forms of a chemical?
-Solids - least likely to cause chemical poisoning unless ingested
-Dusts - tiny particles of solids - cement - they can breathed (inhaled) - really small particles can be absorbed into the bloodstream and travel to other
parts of the body where they can cause damage.
-Liquids - acids, solvents . mercury passes through the skin into the bloodstream
-Mists - From a shower = Legionella The droplets are less than 20um in size
-Vapours can be invisible
-Gases carbon monoxide
-Fibres -Fibres of 0.5 μm or less can enter the lungs and become trapped in the alveoli. These can cause lung damage e.g. scarring (fibrosis), with a resulting loss of lung function. Larger fibres may be ingested by macrophages.

Question 43

What are the body’s defence to chemicals

Answer 43

What are the body’s defence to chemicals
STORE the toxic material e.g. the bones and the brain (lead in bones)
NEUTRALISE it e.g. the liver
REMOVE it from the body e.g. the kidney and bladder

Question 44

What are the two types of defence for the body?

Answer 44

What are the two types of defence for the body?
BASIC - preventing the chemical or biological agent entering the body:
--the skin
--the eye
--the respiratory system
--the digestive system
AUTO-IMMUNE attacking the agent directly
--innate (non-specific)
--adaptive (specific)

Question 45

Lungs Defence

Answer 45

irritant dust that settles in the nose may lead to rhinitis, an inflammation of the mucous membrane. If the
particle attacks the larger air passages, inflammation of the trachea (tracheitis) or the bronchi (bronchitis) may be seen.
When a person breathes in, particles suspended in the air enter the nose, but not all of them reach the lungs. The nose is an efficient filter. large particles
stopped by the nasal hairs, removed by blowing the nose or sneezing.
Some of the smaller particles make it to the bronchi and bronchioles. Airways are lined by
cells. The mucus they produce catches most of the dust particles. Tiny hairs called cilia, covering the walls of the air tubes, move the mucus upward and out into the
throat, where it is either coughed up and spat out, or swallowed.
The air reaches the tiny air sacs (alveoli) in the inner part of the lungs with any dust particles smaller than 5-7 μm. The alveoli are very important because through
them, the body receives oxygen and releases carbon dioxide.
Dust that reaches the lower part of the airways and the alveoli (where there are no cilia) is attacked by special cells called macrophages. These are extremely
important for the defence of the lungs. They keep the air sacs clean. Macrophages virtually swallow the particles in a process known as phagocytosis. Then the
macrophages, in a way which is not well understood, reach the part of the airways that is covered by cilia. The wavelike motions of the cilia move the macrophages
which contain dust to the throat, where they are spat out or swallowed. If the amount of dust is large, the macrophage system may fail. Dust particles and dust-containing macrophages collect in the lung tissues, causing injury to the lungs. The amount of dust and the kinds of particles involved influence how serious the
lung injury will be e.g. after the macrophages swallow silica particles, they die and give off toxic substances. These substances cause fibrous or scar tissue to form.
This tissue is the body’s normal way of repairing itself. The general name for this condition for fibrous tissue formation and scarring is fibrosis e.g. crystalline silica,
causes a condition called silicosis; coal causes pnuemoconiosis. Besides macrophages, the lungs have another system for the removal of dust. The
lungs can react to the presence of germ-bearing particles by producing certain proteins. These proteins attach to particles to neutralise them.
Some small particles, less than 5μm, may dissolve in the bloodstream. The blood then carries the substance around the body where it may affect the brain, kidneys
and other organs. Smaller particles, less than 5μm may also be breathed out.
– Size and heaviness of the particles are important because large and heavy
particles settle more rapidly.
– Chemical composition is important because some substances, when in
particle form, can destroy the cilia that the lungs use for the removal of particles.
– Cigarette smoking may alter the ability of the lungs to clear themselves.
– Breathing rates: the amount of dust settling in the lungs increases with the
length of time the breath is held and how deeply the breath is taken which
means manual labourers exerting themselves are at greater risk than sedentary
workers.
– Breathing is through the nose or mouth is also important. If breathing
through the mouth the first defence mechanism of the nose is by passed.

Question 46

Digestive system defence

Answer 46

Chemicals entering the digestive system will have to survive acid and enzymes in
the mouth, stomach and intestines.
The body tries to remove certain toxic substances from the digestive system by
causing vomiting and diarrhoea. These are immediate responses and their aim is to
remove the toxic chemicals as quickly as possible. However, these response
mechanisms cannot remove all ingested hazardous agents from the body.
The remainder of the chemicals will be dealt with by the kidneys and liver.

Question 47

Skin defence

Answer 47

The average adult has 1.6 square metres of skin forming a barrier between the body’s internal organs and the outside world. Bacteria and micro-organisms cannot
pass through unbroken skin, and they are prevented from multiplying by the action of oily sebum secreted by the sebaceous glands at the root of the hair follicles.
Sweat also contains antibacterial lactoferrin.
However, if the skin is broken, by a cut or graze, bacteria and micro-organisms can get into the body and the immune system has to send white blood cells to kill them.
Chemicals are released that cause the area to become red, hot and inflamed as blood vessels widen to speed white blood cells to the site resulting in blisters,
rashes and inflammation.
Some chemicals can pass through unbroken skin, but only very slowly. Thus the nicotine in nicotine patches makes its way into the bloodstream, and so do certain
toxic chemicals e.g. insecticides and solvents, which can then cause systemic illhealth.
Melanin protects the skin from UV light from the sun and the sensory nerves alert the brain to pain.

Question 48

Dermatitis

Answer 48

Dermatitis is inflammation of the skin caused by contact with a range of materials.
These include detergents, toiletries, chemicals and even natural products like foods and water (if contact is prolonged or frequent). It can affect all parts of the body, but it is most common to see the hands affected. There are different types of contact dermatitis:
–Irritant dermatitis (sometimes known as ‘primary’ dermatitis).
–Allergic dermatitis.

Irritant dermatitis is usually caused by chemicals etc. that dry out and damage the skin. It can occur quickly after contact with a strong irritant, or over a longer period
from repeated contact with weaker irritants. Irritants can be chemical, biological, mechanical or physical. Repeated and prolonged contact with water (e.g. more
than 20 hand washes or having wet hands for more than 2 hours per shift) can also cause irritant dermatitis.

Allergic dermatitis can occur when the sufferer develops an allergy to a substance. Once someone is ‘sensitised’, it is likely to be permanent and any skin contact with that substance will cause allergic contact dermatitis. Often skin sensitisers are also irritants. The allergic reaction can show up hours or days after contact.

Question 49

Controlling dermatitis

Answer 49

.

Question 50

immune system defence

Answer 50

When pathogens enter the body, the immune system attempts to destroy them.
Inside the body, pathogens behave in different ways:
–Viruses reproduce inside cells and damage them and escape to infect more cells.
–Bacteria produce ‘toxins’ or ‘poisons’.
Both cell damage and toxins cause the symptoms of infectious diseases.
The innate (non-specific) immune system is the first line of defence against invading micro-organisms. The innate immune system exists at birth, and does not change very much through life. It responds rapidly to infection, but has neither memory nor any specificity.
The main cells used in the innate system are phagocytes which are attracted to an organism, bind to it, engulf it by endocytosis and release cytotoxic materials to kill
it. Digestive enzymes are then released onto the organism. The process is known as phagocytosis.
The adaptive (specific) immune system produces a slower response than that of the innate immune system, but the response is highly specific. Each lymphocyte is
antigen specific (an antigen is the foreign substance on the surface of an invading organism). The adaptive system has a memory and therefore mounts a fast immune response to previously encountered microbes.

Question 51

Classification of chemicals

Answer 51

Toxic - chemical that at low levels cause damage to health (death, acute, chronic or ill health)
Harmful - chemical that may cause damage to health
Corrosive - chemicals that may destroy living tissue
Irritant- chemicals that may cause inflammation to the skin ro other mucous membranes

Question 52

Safety data sheet should contain……

Answer 52

A safety data sheet should be dated and contain the following headings
 Identification of the substance/mixture and of the company/undertaking
 Hazards identification
 Composition/information on ingredients
 First-aid measures
 Fire-fighting measures
 Accidental release measures
 Handling and storage
 Exposure controls/personal protection
 Physical and chemical properties
 Stability and reactivity
 Toxicological information
 Ecological information
 Disposal considerations
 Transport information
 Regulatory information
 Other information.

Question 53

Sensitising

Answer 53

Sensitising
Substances and preparations which, if they are inhaled or if they penetrate the skin, are capable of eliciting a reaction by hypersensitisation such that on
further exposure to the substance or preparation, characteristic adverse effects are produced.
Sensitising chemicals are substances and preparations which are capable of eliciting a reaction of hypersensitisation. This means that adverse effects are
produced on further exposure to the chemical. Sensitisation may be brought about
by either:
 Inhalation, producing asthma or hay-fever like symptoms.
 Skin contact, causing allergic contact dermatitis.
Skin sensitisation resulting in dermatitis is a common occupational and environmental health issue. Many hundreds of chemicals have been implicated as
skin sensitisers, including commonplace substances such as nickel and turpentine.
Likewise, respiratory sensitisation can be caused by commonly used chemicals like formaldehyde. Once a person has become sensitised, the condition lasts
throughout their lifetime and so sensitising substances have no ‘safe’ exposure.

Question 54

Carcinogenic

Answer 54

Carcinogenic
Substances and preparations which, if they are inhaled or ingested or if they penetrate the skin, may induce cancer or increase its incidence.
A carcinogen is an agent which has the ability to cause cancer or malignant tumours. This is an example of a delayed health effect which affects the cell reproduction mechanism resulting in the uncontrolled growth and spread of abnormal cells in the body. There are many kinds of cancer.
Exposure to some chemicals, such as benzene and asbestos, can produce cancer in humans. Some chemicals produce cancer in animals, but whether they will in humans is unknown. Because cancer may not appear until 5 to 40 years after exposure, determining the cause of cancer is difficult.
There is no threshold of harm for a carcinogen i.e. there is no ‘safe’ level of exposure. The effects of cancer are irreversible.

Question 55

Carcinogenic

Answer 55

Carcinogenic
Category 1- Proven human carcinogens e.g. benzene, arsenic, chromium VI, asbestos
Category 2-Suspected carcinogens e.g. cadmium compounds, beryllium compounds, sodium dichromate
Category 3-Animal studies indicate a link, but there is no proven human link

Question 56

Mutagenic

Answer 56

Mutagenic
Substances and preparations which, if they are inhaled or ingested or if they penetrate the skin, may induce heritable genetic defects or increase their
incidence.
Chemical mutagens are those compounds that increase the frequency of some types of mutations. They vary in their potency since this term reflects their ability to
enter the cell, their reactivity with DNA, their general toxicity, and the likelihood that the type of chemical change they introduce into the DNA will be corrected by a repair system.

Question 57

Toxic for reproduction

Answer 57

..Flamdycide
Toxic for reproduction
Substances and preparations which, if they are inhaled or ingested or if they penetrate the skin, may produce or increase the incidence of non-heritable adverse effects in the progeny and/or of male or female reproductive
functions or capacity.
Chemicals that are toxic for reproduction will interfere in some way with normal reproduction. Exposure:
 Can affect a man’s or woman’s reproductive system by making the production of normal sperm or eggs more difficult.
 May act directly on an unborn baby (foetus).
Since chemicals can be transferred from the mother’s blood to the unborn baby’s blood, the foetus can be affected when the mother is exposed to certain chemicals.
A pregnant woman who drinks alcohol can have a baby with foetal alcohol syndrome. The health effects can range from birth defects to learning disabilities.

Question 58

Workplace chemical

Asbestos

Answer 58

..

Question 59

Workplace chemical

Cromium and compounds

Answer 59

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Question 60

Workplace chemical

Isocyanates

Answer 60

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Question 61

Workplace chemical

Lead

Answer 61

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Question 62

Workplace chemical

Siliceous dusts

Answer 62

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Question 63

Workplace chemical

Sodium hydroxide

Answer 63

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Question 64

Workplace chemical

Sulphuric acid

Answer 64

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Question 65

Workplace chemical

Trichloroethylene

Answer 65

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Question 66

Workplace chemical

Wood dust

Answer 66

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Question 67

What is toxicology

Answer 67

Toxicology is the science of adverse effects of chemical substances on living organisms

Question 68

toxicology studies aim to access the adverse effects related to different doses in order to find this acceptably safe level
what are the two phases

Answer 68

1) by collecting data on the properties of chemicals, results of studies and accidental misuse of chemicals
2) by predicting the effect of chemicals in different situations

to make relevant predictions there must be information available on the

• substance and its chemical and physical properties
• biological system addicted
• effects or response caused by the substance
• exposure (dose, time, situation)

this information is obtained from laboratory tests with cells, bacteria, animals, epidemiological studies and from accidents involving the substance

Question 69

What does vitro mean

Answer 69

What does vitro mean within glass

Question 70

What does in vivo mean

Answer 70

.

Question 71

Hazard classes

Very Toxic

Answer 71

Very Toxic
Substances and preparations which, at very low levels, may cause death, acute or chronic damage to health when inhaled, swallowed or absorbed via the skin.

Very toxic, toxic and harmful are all classifications which relate to how ‘poisonous’ a chemical agent is. Toxicity is measured in the lethal dose required to kill 50% of a
rat population and is measured in the number of g/kg. This is termed the ‘LD50’,

Question 72

Hazard classes

Toxic

Answer 72

Toxic
Substances and preparations which, at low levels, may cause death, acute or chronic damage to health when inhaled, swallowed or absorbed via the skin.

Very toxic, toxic and harmful are all classifications which relate to how ‘poisonous’ a chemical agent is. Toxicity is measured in the lethal dose required to kill 50% of a
rat population and is measured in the number of g/kg. This is termed the ‘LD50’,

Question 73

Harmful

Answer 73

Harmful
Substances and preparations which may cause death, acute or chronic damage to health when inhaled, swallowed or absorbed via the skin.

Very toxic, toxic and harmful are all classifications which relate to how ‘poisonous’ a chemical agent is. Toxicity is measured in the lethal dose required to kill 50% of a
rat population and is measured in the number of g/kg. This is termed the ‘LD50’,

Question 74

Corrosive

Answer 74

Corrosive
Substances and preparations which may, on contact with living tissues, them.
A corrosive substance can destroy human tissue with which it comes into contact.
The main hazards to people include damage to the eyes, the skin, and the tissue under the skin. Inhalation or ingestion of a corrosive substance can damage the
respiratory and gastrointestinal tracts. Exposure results in chemical burn similar to a thermal burn.

Corrosives are different from poisons in that corrosives are immediately dangerous to the tissues they contact, whereas poisons may have systemic toxic effects that require time to become evident.
Common corrosive chemicals are classified into:
Acids
 Strong acids: the most common are sulphuric acid, nitric acid and hydrochloric
acid (H2SO4, HNO3 and HCl, respectively).
 Some concentrated weak acids e.g. formic acid and acetic acid.

Bases
 Caustics or alkalis e.g. sodium hydroxide (NaOH) and potassium hydroxide (KOH).
 Alkali metals in metallic form e.g. elemental sodium; and hydrides of alkali and alkaline earth metals e.g. sodium hydride.
 Extremely strong bases e.g. metal amides: sodium amide.
 Some concentrated weak bases e.g. ammonia when crystalline (anhydrous) or
in a concentrated solution.

Acids and bases are two extremes on the pH scale. Mixing acids and bases can cancel out or neutralize their extreme effects. A substance that is neither an acid
nor a base is neutral.
The pH scale measures how acidic or basic a substance is. The pH scale ranges
from 0 to 14. A pH of:
 7 = neutral
 7 = a base (8-14).
The pH scale is logarithmic so an acid of pH 5 is ten times stronger than an acid of
pH 6.

Question 75

Irritant

Answer 75

Irritant
Substances and preparations which, through immediate and prolonged or repeated contact with the skin or mucous membrane, may cause inflammation.
Irritants are substances that cause significant inflammation of the skin, persisting for more than 24 hours, or that cause defatting. Irritation of the eyes by substances classified as irritants can cause permanent damage.
A simple reaction to an irritant is local and is not normally extreme. However some irritants can provoke an allergic response and can give rise to occupational asthma
or dermatitis. These substances are also sometimes classified as ‘harmful’.
Examples include pollens and flour dust.