02_hazardous_substances_and_other_chemicals_assessment_of_risk_20140117153011

Question 1

In order to achieve the above it is necessary to consider a range of factors in each CoSHH risk assessment. 12

Answer 1

1. The hazardous properties of a substance2. ExposureD. durationA. activitiesF. frequencyT. thresholdsT. typeL. levelN. no. of people3. Route of entry 4. Particle size of solids 5. Volatility of liquids 6. Concentration7. Solubility8. The nature of the task 9. Mixtures of chemicals10. Effectiveness of existing control measures 11. Results from health surveillance and monitoring 12. Individual susceptibilities

Question 2

LD 50 :

Answer 2

the ingested dose which kills 50% of the test population, measured in milligrams/micrograms per kilogram of body weight.

Question 3

LC 50 :

Answer 3

airborne concentration of a toxic substance lethal to 50% of the test population, measured in millilitres per kilogram of body weight.

Question 4

The nature of the task will also affect exposure to hazardous substances. Employees may be exposed: 5

Answer 4

 Directly i.e. by doing the task  Indirectly i.e. by passive exposure to the hazardous substance in the work area  Undertaking cleaning or maintenance tasks  By contact with contaminated work areas, clothing etc.  Accidental release of a hazardous substance.

Question 5

Mixtures of chemicals 4

Answer 5

Additive effects: The combined effect equals the sum of the effects of each chemical alone, i.e. 1 + 1 = 2 Synergistic effects: The combined effect is larger than the sum of the effects of each chemical alone, i.e. 1 + 1 = 40. Antagonistic effects: The combined effect is less than the sum of the effects of each chemical alone, i.e. 1 + 1 = 0. Potentiating effects: A chemical that normally has no effect will increase the effect that another chemical would have alone, i.e. 0 + 1 = 3

Question 6

Individual susceptibilities Employers are required to protect particular groups of employees who may be at an increased risk, for example: 7

Answer 6

 Inexperienced trainees and young people aged under 18  Pregnant workers  Disabled workers  Any employees known to be susceptible to certain illnesses such as dermatitis  Any employee suffering atopic (allergic) asthma due to pollen, or eczema due to dust mites etc. may consequently be at more risk of sensitisation to a work exposure to a sensitising agent  Any employee known to be previously sensitised to a work based skin or asthma sensitising agent  Any employee with pre-existing medical conditions, which could be made worse by exposure to chemicals.

Question 7

The principles of good COSHH practice are: 8

Answer 7

1) Design and operate processes and activities to minimise emission, release and spread of substances hazardous to health. 2) Take into account all relevant routes of exposure. 3) Ensure control measures are proportionate to the health risk. 4) Choose the most effective and reliable control options to minimise the escape and spread of hazardous substances. 5) Where adequate control cannot be achieved by other means, provide, in combination with other control measures, suitable personal protective equipment (PPE). 6) Check and regularly review control measures to ensure their continuing effectiveness. 7) Inform and train all employees on the hazards and risks and the control measures developed to minimise the risks. 8) Ensure that the introduction of control measures does not increase the overall risk to health and safety.

Question 8

Sources of exposure should be reduced by: 3

Answer 8

number, size, emission or release rate

Question 9

PPE tends to be less effective and reliable than other control options, because it: 7

Answer 9

 Has to be selected for the individual  Has to fit the individual and not interfere with their work or other PPE worn at 
the same time  Has to be put on correctly every time it is worn  Has to remain properly fitted all the time the individual is exposed  Has to be properly stored, checked and maintained  Tends to be delicate and relatively easily damaged  Fails to danger, sometimes without warning.

Question 10

‘Software’ controls:

Answer 10

defined methods of working, supervisory actions, record keeping etc.

Question 11

‘Hardware’ controls:

Answer 11

example: local exhaust ventilation (LEV).

Question 12

The hierarchy concentrates on ‘control of source’ (collective measures) as the most effective and reliable and ‘individual measures’ (those relying on people to do/wear etc.) as the least effective and efficient: 6

Answer 12

 Eliminate the hazard, or substitute for a less harmful substance  Change the form of the substance  Modify the process to emit less of the hazardous substance  Engineering controls, for example: local exhaust ventilation (LEV)  Minimise the number of workers exposed  Personal Protective Equipment (PPE).

Question 13

The use or production of hazardous substances may be eliminated by: 3

Answer 13

 Changing the method of work eliminate the task so that exposure is no longer necessary  Modifying a process to eliminate the production of a hazardous by-product or waste product  Substituting wherever reasonably practicable, a hazardous substance for a non-hazardous substance, for example: water based pint instead of oil based paint.

Question 14

Carcinogenic Category 1

Answer 14

Substances known to cause cancer on the basis of human experience

Question 15

Carcinogenic Category 2

Answer 15

Substances which it is assumed can cause cancer on the basis of reliable animal evidence

Question 16

Carcinogenic Category 3

Answer 16

Substances where there is only evidence in animals which is of doubtful relevance to human health (i.e. the evidence is not good enough for Category 1 or 2)

Question 17

An employer could use the following information sources when
investigating whether carcinogens or mutagens are used in the workplace: 11

Answer 17

 Chemical labels  Safety data sheets (SDS’s) for substances used in the workplace, particularly relevant risk phrases  Annex VI of the CLP Regulation for classification as carcinogen  The European Chemicals Agency candidates list or list for substances of very high concern (SVHC)  Schedule 1 of CoSHH  By the application of the criteria in CHIP in a self-classifying approach for new substances  EH40 Workplace Exposure Limits  Scientific papers  Information from trade associations  The Chemical Industry Association  The International Labour Organization.

Question 18

Additional control measures specified for controlling the risk of exposure to carcinogens and mutagens include: 5

Answer 18

 Totally enclosing the process and handling systems (unless not reasonably practicable).  Prohibiting eating, drinking and smoking in areas that may be contaminated by carcinogens or mutagens.  Cleaning floors, walls and other surfaces regularly and as necessary.  Clearly designating areas and installations that may be contaminated by carcinogens or mutagens and posting warning signs.  Storing, handling and disposing of carcinogens or mutagens safely, including using closed and clearly labelled containers.

Question 19

In addition to the information specified by CoSHH and the ACOP, employees and their safety representatives, and any other people likely to be exposed to carcinogenic or mutagenic substances, should be kept aware of: 3

Answer 19

 The type or form of the risk  The special features of carcinogenic and mutagenic substances  The circumstances in which they may be exposed to carcinogenic or mutagenic substances.

Question 20

If the control limit for asbestos is exceeded in the working area, this triggers particular requirements including: 6

Answer 20

 Immediately informing employees and their representatives  Identification of the reasons for the control limit being exceeded and the introduction of appropriate measures to prevent it being exceeded again  Stopping work until adequate measures have been taken to reduce employees’ exposure to below the control limit  A check of the effectiveness of the measures taken to reduce the levels of asbestos in the air by carrying out immediate air monitoring  The designation of respirator zones  The mandatory provision of respiratory protective equipment, although such equipment should always be provided if it is reasonably practicable to do so.

Question 21

The Control of Asbestos Regulations requires the person in control of maintenance activities in non-domestic premises, (for example: occupier, landlord, or managing agent) to manage the risk from asbestos in the premises, and to ensure that a suitable and sufficient assessment is carried out as to whether asbestos is or is liable to be present in the premises. The duty to manage requires the duty holder to: 8

Answer 21

 Take reasonable steps to find out if asbestos containing materials (ACM) are present and if so establish the amount, its condition and location.  Presume materials contain asbestos unless there is strong evidence that they do not.  Make, and keep up-to-date, records of the location and condition of the ACM and presumed ACM.  Assess the risk of anyone being exposed to fibres from the materials identified.  Prepare a plan that sets out in detail how the risks from these materials will be managed.  Take the necessary steps to put the plan into action.  Periodically review and monitor the plan and the arrangements to act on it so that the plan remains relevant and up-to-date.  Provide information on the location and condition of the materials to anyone who is liable to work on or disturb them.

Question 22

There are two types of survey for asbestos containing material (ACM):

Answer 22

 A management survey.  A refurbishment / demolition survey.

Question 23

Work within the scope of licensing includes work with: 3

Answer 23

 Asbestos insulation  Asbestos coatings (excluding most work with textured decorative coatings containing asbestos)  Asbestos insulating board.

Question 24

If the work with asbestos is licensed the employer should:

Answer 24

 Notify the enforcing authority  Provide medical surveillance for employees  Maintain health records for employees  Prepare emergency procedures in case of emergencies  Designate the work area as an asbestos area and, if the control limit is likely to be exceeded, as a respirator zone. Asbestos and respirator zones should be clearly and separately marked.

Question 25

Regulation 3(2) (Application of CAR) specifies that asbestos work will not need to be licensed under the following conditions: 6

Answer 25

 The exposure of employees to asbestos is sporadic and of low intensity  It is clear from the risk assessment that the exposure of any employee to asbestos will not exceed the control limit  The work involves: - Short, non-continuous maintenance activities - Removal of materials in which the asbestos fibres are firmly linked in a matrix - Encapsulation or sealing of asbestos-containing materials which are in good condition - Air monitoring and control, and the collection and analysis of samples to ascertain whether a specific material contains asbestos.

Question 26

Sporadic and low intensity exposure to asbestos: this applies where a suitable and sufficient risk assessment of clearly shows that work:

Answer 26

 Does not expose workers to more than the ten-minute control period (STEL) of 0.6 fibres per cubic centimetre (0.6 f/cm3) in the air.

Question 27

The control limit will not be exceeded (asbestos): this applies where a suitable and sufficient risk assessment of clearly shows that the concentration of asbestos in the air will not: 3

Answer 27

 exceed the 4 hour control limit (LTEL) of 0.1 fibres per cubic centimetre (0.1 f/cm3) airborne fibres  If the work takes less than a total of: - 1 hour in seven consecutive days by one person - 2 hours in seven consecutive days by more than one person.  Materials in which the asbestos fibres are firmly linked in a matrix

Question 28

Materials in which the asbestos fibres are firmly linked in a matrix: 4

Answer 28

- Asbestos cement - Textured decorative coatings and paints which contain asbestos - Any article of bitumen, plastic, resin or rubber which contains asbestos 
where its thermal or acoustic properties are incidental to its main purpose (for example: vinyl floor tiles, electric cables, roofing felt) - Other materials in which the asbestos fibres can be firmly linked in a matrix, for example: paper linings, cardboards, felt, textiles, gaskets, washers, and rope where the products have no insulation purposes - Encapsulation and sealing of materials in good condition or air monitoring and control, and the collection and analysis of samples to find out if a material contains asbestos.

Question 29

Information, instruction and training Employees and supervisors who work with asbestos should be aware of the following: 11

Answer 29

 The properties of asbestos and its effects on health, including its interaction with smoking.  The types of products or materials likely to contain asbestos.  The operations which could result in asbestos exposure and the 
importance of preventive controls to minimise exposure.  Safe work practices, control measures, and protective equipment.  The purpose, choice, limitations, proper use and maintenance of 
respiratory protective equipment.  Emergency procedures.  Hygiene requirements.  Decontamination procedures.  Waste handling procedures.  Medical examination requirements.  The control limit and the need for air monitoring.

Question 30

Should asbestos be found in a building, there is a sequence of events to be followed: 6

Answer 30

 Keep people out of the affected area  Seal it off  Reduce air flow through the area by shutting down any ventilation and air conditioning systems  Place signs at the entrance to the area warning of possible asbestos contamination  If contractors or employees have been contaminated with dust bag up any contaminated clothing  Take a sample of the material and send it for analysis to check if it contained asbestos: - If the response is negative, no further action will be necessary. - If the analysis confirms the presence of asbestos, it might be necessary, depending on the scale of the operation, to engage a licensed contractor to take the necessary remedial action and undertake clean-up operations.

Question 31

Employees should be told if their exposure to lead is ‘significant’ i.e.: 3

Answer 31

 Breathing zone: where any employee is or is liable to be exposed to a concentration of lead in the atmosphere exceeding half the occupational exposure limit for lead.  Ingestion: where there is a substantial risk of any employee ingesting lead.  Skin absorption: if there is a risk of an employee’s skin coming into contact with lead alkyls, or any other substance containing lead in a form which can also be absorbed through the skin.

Question 32

If exposure to lead significant, it will be necessary to: 3

Answer 32

 Provide protective clothing  Measure the level of lead in the air, and tell employees the results. 
If exposure to lead cannot be kept below the OEL, respiratory protective equipment (RPE) must be issued.  Arrange to measure the level of lead in the blood and tell employees the results.

Question 33

Action/Suspension levels for lead

Answer 33

Action SuspensionGeneral employee 50 μg/100ml 60 μg/100ml Young person under 18 40 μg/100ml 50 μg/100ml Woman of child bearing age 25 μg/100ml 30 μg/100ml

Question 34

Information, instruction and training (Regulation 11) Employees should be provided with information, instruction and training including: 5

Answer 34

 Details of the form of lead to which the employee is liable to be exposed including: - the risk which it presents to health - any relevant occupational exposure limit, action level and suspension level - access to any relevant safety data sheet - other legislative provisions which concern the hazardous properties of that form of lead.  The significant findings of the risk assessment.  The appropriate precautions and actions to be taken by the employee in 
order to safeguard himself and other employees at the workplace.  The results of any monitoring of exposure to lead.  The collective results of any medical surveillance undertaken (without the results being identified as relating to a particular person).

Question 35

(a) Identify the published sources of information an employer could use to determine if carcinogens are used in their workplace. 4 marks

Answer 35

Sources of information include:  Labels and Safety Data Sheets for substances used in the workplace and in particular the relevant R (risk) phrases  Annex VI of the CLP (Classification, Labelling and Packaging) Regulation for classification as carcinogen  the European Chemicals Agency candidates list or list for SVHC (substances of very high concern)  Schedule 1 of COSHH (Control of Substances Hazardous to Health regulations)  Application of the criteria in CHIP (chemicals (hazard information and packaging for supply) regulations), in a self-classifying approach, which would be particularly relevant if a new substance was involved  Technical reference sources including: - EH40 (workplace exposure limits for use with the COSHH regulations) - scientific papers - information from trade associations, such as the Chemical Industry Association and the International Labour Organisation.

Question 36

(b) Outline control measures that should be used when, because of the nature of the work, it is not possible to eliminate a carcinogen or substitute it with and alternative substance. 16 marks

Answer 36

Required control measures would be guided by the requirements in Regulation 7 of the COSHH Regulations and the associated ACoP on carcinogens. These would include:  Reducing exposure to a level as low as reasonably practicable by minimising quantities used and/or changing the physical form.  Use of a totally enclosed system, or automation of the process to physically separate workers from the process and, where this is not possible, the use of a partial enclosure in the workplace, or appropriate local exhaust ventilation.  Providing appropriate storage, including the use of closed/sealed containers, and recognition that it may be better to store one large quantity in a controlled manner than to deal with frequent supplies of smaller amounts.  Correctly labelled materials and the areas of use restricted with identifying signs to indicate their boundaries.  Any waste carcinogenic products should be labelled and stored in a secure area pending removal by a specialist contractor.  The numbers working in the restricted areas should be minimised and non-essential personnel excluded.  Precautions should also be taken against contamination including prohibiting eating, drinking and applying cosmetics in contaminated areas; providing appropriate warning signs to demark these areas; and providing adequate washing facilities.  Monitoring of levels of exposure should be carried out on a regular basis to ensure the adequacy of the control measures in place, with the recognition that the use of personal protective equipment can only be used as a secondary control in combination with other controls.

Question 37

(b) Explain THREE of the ‘principles of good practice’ that should be considered when deciding if the control of exposure can be treated as ‘adequate’ under the Control of Substances Hazardous to Health Regulations (COSHH). 3 marks

Answer 37

Examples of the principles of good practice that should be considered when deciding if the control of exposure can be treated as ‘adequate’ under COSHH include:  those dealing with design and operation of the processes and activities to minimise emission  the need to take into account all relevant routes of exposure not just inhalation  the need for the periodic checking and review of control measures to ensure their continuing effectiveness  the occasions when personal protective equipment may have to be used alongside other control measures  the provision of information and training to employees the need to avoid increasing the overall risk to health and safety by the introduction of selected control measures.

Question 38

A company is considering substituting a solvent it currently uses for one that is thought to be more effective. Outline the factors affecting health that should be considered before a decision is taken to make the change.

Answer 38

Factors associated with the proposed replacement include:  information contained on the manufacturer’s data sheet with respect, for example, to its toxicity, the harm that it might cause and its exposure limits  the form of the substance, whether liquid or spray  the quantity to be used and the changes that might have to be made in the process times  the possible routes of entry of the solvent to the body  the number of people likely to be exposed  the level and frequency of exposure, taking into account personal susceptibilities and groups especially at risk, such as young employees  the control measures that would be required, such as the provision of local exhaust ventilation and personal protective equipment  whether specific requirements would be required for the storage of the solvent  what arrangements would have to be made for its safe disposal.

Question 39

A facilities manager of a multi-occupancy office block built in the 1970s is concerned about the risks associated with asbestos in the building. (a) Outline the steps the facilities manager should take to minimise risks associated with any asbestos that may be present in the building. 12 marks

Answer 39

The facilities manager should initially accept that his/her company is the duty holder who has the responsibility to manage asbestos in the multi-occupancy building and should assume that because of the age of the building that asbestos will be present. They should then identify all materials in the building that might contain asbestos and arrange for a competent person to undertake a survey using intrusive and destructive sampling to determine the presence or absence of the material. A record would have to be kept of where asbestos containing materials (ACMs) are located and updated following regular reviews of their condition. The information should be made available to all tenants in the block. Finally consideration would need to be given to what action was necessary to deal with the various ACMs whether to remove, repair, enclose or leave in place and an action plan drawn up once the decisions had been made.

Question 40

(b) An occupant of one of the offices engages a contractor to fit a hand dryer in a toilet which involves drilling through some asbestos insulating board. Outline the required steps to be taken by the contractor to carry out this work, in accordance with the Control of Asbestos Regulations 2006. 8 marks

Answer 40

The work to be carried out is of short duration and therefore classed as non-licensed. However, precautions would be necessary and whilst the work was being carried out:  Access to the toilet should be restricted, the door closed and a warning sign displayed.  The fixtures and surfaces in the toilet would have to be covered with a polythene sheet fixed with tape, paste or foam used to coat the drill entry point and a hand drill used to make the required hole which should then be lined or sleeved to prevent fibre release.  The paste would have to be cleaned off with damp cloths and all waste double bagged and disposed of as asbestos waste.  The complete area where the work was carried out and the equipment used would need to be cleaned down with a type H vacuum.  The person carrying out the work should be fully informed of its related hazards and the precautions to be observed including the wearing of personal protective equipment such as disposable overalls and the appropriate respirator.

Question 41

(a) Explain the meaning of the term ‘carcinogen’. 2 marks

Answer 41

A ‘carcinogen’ is an agent that causes cancer; has the ability to produce malignant tumours, attacks cell reproduction mechanisms; causes changes in cell’s DNA resulting in abnormal cells and uncontrollable growth; and produces effects that are irreversible and continue well after the initial exposure.

Question 42

(b) Outline the role of Workplace Exposure Limits (WELs) when deciding if exposure to a carcinogen is ‘adequately controlled’ for the purposes of the Control of Substances Hazardous to Health (COSHH) Regulations 2002. 2 marks

Answer 42

Exposure to a carcinogen is adequately controlled when a WEL, if one exists, is not exceeded and when exposure is reduced to the lowest level that is reasonably practicable.

Question 43

(c) Under COSHH exposure to substances hazardous to health (including carcinogens) shall only be treated as adequate if the ‘principles of good practice’ are applied. Outline SIX of these principles.

Answer 43

Examples of the principles of good practice that should be considered when deciding if the control of exposure can be treated as ‘adequate’ under COSHH include:  those dealing with design and operation of the processes and activities to minimise emission  the need to control exposure by measures that are proportionate to the health risk  the choice of the most effective and reliable control options which minimise the escape and spread of the substances hazardous to health  the need to take into account all relevant routes of exposure not just inhalation  the need for the periodic checking and review of control measures to ensure their continuing effectiveness  the provision of suitable personal protective equipment when adequate control of exposure cannot be completely achieved by other means  the provision of information and training to employees on the hazards and risks from the substances they use in their work and the use of the control measures that have been introduced to minimise the risks  the need to ensure that the introduction of the selected control measures does not increase the overall risk to health and safety.

Question 44

(b) A company uses a substance in the form of a powder, which is added directly to a mixing vessel from sacks, during the manufacture of paints. Outline the practical control measures that could be used to minimise exposure during the addition. 8 marks

Answer 44

Elimination of the coloured powder was not an option since the colour range was required, so following the rest of the hierarchy of control the other practical control measures included:  Introducing the colouring agent in a pellet or dye solution form ... or ...  The powder could be fed into the mixing vessel by means of an automated hopper feed system and screw conveyor with the powder being emptied into the hopper through an opening provided with local exhaust ventilation.  A vacuum cleaner should be used to clear up spillages.  Employees should be provided with personal protective equipment such as overalls, gloves and goggles.  Some form of respiratory protection would also have to be provided. If the dust was thought to be nuisance only, then a particle filtering face piece – a disposable face mask – changed on a regular basis could suffice. However, a filter respirator would have to be worn if the powder were found to be harmful.