July 2008
Examiners’ Report NEBOSH International Diploma in Occupational Health and Safety (Unit IB)
Examiners’ Report NEBOSH INTERNATIONAL DIPLOMA IN OCCUPATIONAL HEALTH AND SAFETY Unit IB – International control of hazardous agents in the workplace JULY 2008
CONTENTS
Introduction
2
General Comments
3
Comments on individual questions
4
© 2008 NEBOSH, Dominus Way, Meridian Business Park, Leicester LE19 1QW tel: 0116 263 4700
fax: 0116 282 4000
email:
[email protected]
website: www.nebosh.org.uk
The National Examination Board in Occupational Safety and Health is a registered charity, number 1010444 T(s):exrpts/J/J-B0807
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Introduction
NEBOSH (The National Examination Board in Occupational Safety and Health) was formed in 1979 as an independent examining board and awarding body with charitable status. We offer a comprehensive range of globally-recognised, vocationally-related qualifications designed to meet the health, safety, environmental and risk management needs of all places of work in both the private and public sectors. Courses leading to NEBOSH qualifications attract over 25,000 candidates annually and are offered by over 400 course providers in 65 countries around the world. Our qualifications are recognised by the relevant professional membership bodies including the Institution of Occupational Safety and Health (IOSH) and the International Institute of Risk and Safety Management (IIRSM). NEBOSH is an awarding body to be recognised and regulated by the UK regulatory authorities: • • •
The Office of the Qualifications and Examinations Regulator (Ofqual) in England The Department for Children, Education, Lifelong Learning and Skills (DCELLS) in Wales The Council for the Curriculum, Examinations and Assessment (CCEA) in Northern Ireland
NEBOSH follows the “GCSE, GCE, VCE, GNVQ and AEA Code of Practice 2007/8” published by the regulatory authorities in relation to examination setting and marking (available at the Ofqual website www.ofqual.gov.uk). While not obliged to adhere to this code, NEBOSH regards it as best practice to do so. Candidates’ scripts are marked by a team of Examiners appointed by NEBOSH on the basis of their qualifications and experience. The standard of the qualification is determined by NEBOSH, which is overseen by the NEBOSH Council comprising nominees from, amongst others, the Health and Safety Executive (HSE), the Department for Education and Skills (Df ES), the Confederation of British Industry (CBI), the Trades Union Congress (TUC) and the Institution of Occupational Safety and Health (IOSH). Representatives of course providers, from both the public and private sectors, are elected to the NEBOSH Council. This report on the Examination provides information on the performance of candidates which it is hoped will be useful to candidates and tutors in preparation for future examinations. It is intended to be constructive and informative and to promote better understanding of the syllabus content and the application of assessment criteria. © NEBOSH 2008
Any enquiries about this report publication should be addressed to: NEBOSH Dominus Way Meridian Business Park Leicester LE10 1QW Tel: 0116 263 4700 Fax: 0116 282 4000 Email:
[email protected]
2
General Comments
Many candidates are well prepared for this unit assessment and provide comprehensive and relevant answers in response to the demands of the question paper. This includes the ability to demonstrate understanding of knowledge by applying it to workplace situations. There are always some candidates, however, who appear to be unprepared for the unit assessment and who show both a lack of knowledge of the syllabus content and a lack of understanding of how key concepts should be applied to workplace situations. In order to meet the pass standard for this assessment, acquisition of knowledge and understanding across the syllabus are prerequisites. However, candidates need to demonstrate their knowledge and understanding in answering the questions set. Referral of candidates in this unit is invariably because they are unable to write a full, well-informed answer to the question asked. Some candidates find it difficult to relate their learning to the questions and as a result offer responses reliant on recalled knowledge and conjecture and fail to demonstrate any degree of understanding. Candidates should prepare themselves for this vocational examination by ensuring their understanding, not rote-learning pre-prepared answers. Recurrent Problems It is recognised that many candidates are well prepared for their assessments. However, recurrent issues, as outlined below, continue to prevent some candidates reaching their full potential in the assessment. −
Many candidates fail to apply the basic principles of examination technique and for some candidates this means the difference between a pass and a referral.
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In some instances, candidates are failing because they do not attempt all the required questions or are failing to provide complete answers. Candidates are advised to always attempt an answer to a compulsory question, even when the mind goes blank. Applying basic health and safety management principles can generate credit worthy points.
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Some candidates fail to answer the question set and instead provide information that may be relevant to the topic but is irrelevant to the question and cannot therefore be awarded marks.
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Many candidates fail to apply the command words (also known as action verbs, eg describe, outline, etc). Command words are the instructions that guide the candidate on the depth of answer required. If, for instance, a question asks the candidate to ‘describe’ something, then few marks will be awarded to an answer that is an outline.
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Some candidates fail to separate their answers into the different sub-sections of the questions. These candidates could gain marks for the different sections if they clearly indicated which part of the question they were answering (by using the numbering from the question in their answer, for example). Structuring their answers to address the different parts of the question can also help in logically drawing out the points to be made in response.
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Candidates need to plan their time effectively. Some candidates fail to make good use of their time and give excessive detail in some answers leaving insufficient time to address all of the questions.
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Candidates should also be aware that Examiners cannot award marks if handwriting is illegible.
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UNIT IB – International control of hazardous agents in the workplace
Section A – all questions compulsory
Question 1
(a)
(b)
Outline the four stages of occupational health and hygiene practice.
(4)
An organisation is concerned about the level of absence arising from work related injuries and ill-health. Suggest practical ways in which the organisation’s occupational health department could assist in the management of this problem.
(6)
The first stage in occupational health and hygiene practice is recognising and identifying hazards that can cause harm in the workplace. This would be followed by taking measurements to determine who might be affected and to what extent. Once the measurements have been completed, an evaluation of the level of risk posed by the identified hazards will have to be carried out and this will point to the need to introduce control measures to eliminate or minimise the risk. There are a number of practical ways in which the organisation’s occupational health department might assist in managing the problem described such as: using preemployment screening to identify potential employees who would be at a greater risk of suffering ill-health resulting in absence; carrying out regular health surveillance of existing employees engaged in activities with known health hazards; collecting data on sickness absence and analysing it to identify trends in or reasons for absence; liaising with medical practitioners and providing rapid access to treatments such as physiotherapy and counselling which will aid return to work; assisting managers to arrange phased return to work in certain circumstances and providing practical advice on adaptations to work practice to minimise risk of repeat injury; and taking an active part in carrying out risk assessments at the workplace.
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Question 2
Bulldozer drivers at a large construction site have reported incidences of back pain which they believe are caused by exposure to whole body vibration. (a)
(b)
Outline a range of control measures that could be used to minimise the risk of the drivers experiencing back pain caused by exposure to whole body vibration.
(7)
Suggest THREE other possible work-related causes of the back pain being experienced by these bulldozer drivers.
(3)
Control measures that could be used to minimise the risk to bulldozer drivers from exposure to whole body vibration include selecting a vehicle with the size, power and capacity best suited for the terrain and task; organising traffic routes used by bulldozers to avoid as far as possible the need to travel on rough and uneven surfaces; maintaining site roadways and vehicle suspensions; ensuring that an individual’s exposure to whole body vibration is kept below recommended thresholds; fitting suspension seats with vibration damping characteristics and adjusting these to suit the weight of individual drivers to avoid “bottoming out”; organising work patterns including job rotation to ensure that drivers have breaks away from the vehicle and advising them on how to minimise exposure to whole body vibration by avoiding jolts and shocks. In answering part (b), candidates might have suggested other possible work related causes for the back pain such as: poor posture; sitting for long periods of time; the poor layout of controls requiring the driver to stretch and twist to reach a particular control or to obtain good vision; incorrect seat adjustment or no method provided for adjustment which could make hand and foot controls difficult to operate; the repeated climbing into and jumping down from a high cab and carrying out other construction related activities such as the manual handling of heavy loads.
Question 3
Identify a range of information sources an employer could use to determine the extent of employee work-related stress within an organisation.
(10)
There are a number of information sources available in house that employers might use to determine the extent to which their organisations have a work related stress problem. These include data on accidents and levels of sickness absence; health surveillance data; records of staff turnover and poor or erratic timekeeping; the number of complaints received from employees and the grievances or discipline problems that have arisen; information available from the completion of staff questionnaires or from performance appraisals, return to work or exit interviews or informal discussions and the results of an assessment of performance carried out against published management standards.
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Question 4
(a)
(b)
Outline what is meant by the term ‘biological monitoring’ AND indicate circumstances in which such monitoring may be appropriate.
(6)
Outline the practical difficulties that an employer must take into account when introducing a programme of biological monitoring.
(4)
In answering the first part of the question, candidates should have stated that biological monitoring is concerned with the measurement or assessment of hazardous substances or their metabolites in tissues, secretions, excreta or expired air. It is a complementary technique to air monitoring or sampling and can be used to determine if existing controls are adequate; when there is a well established link between the biological monitoring and the effect; when information is required on the accumulated dose in a target organ; when there is a specified guidance value against which a comparison might be made; when there is significant absorption by non-respiratory routes and in circumstances when there is significant reliance on personal protective equipment. For part (b), candidates were expected to identify that, apart from the monitoring required by law, biological monitoring would normally be conducted on a voluntary basis. Consequently the informed consent of those involved would have to be obtained, their concerns overcome and the confidentiality of the results maintained. Other difficulties include the availability of suitable facilities or a location to carry out the monitoring especially if this has to be done at the end of a shift; the availability of specialists to carry out the monitoring for example if blood samples are to be taken; maintaining the integrity of samples to avoid cross contamination and ensuring there was no possibility of cross infection; the fact that there are few guidance values available for comparison; that exposure may be non-occupational and finally the cost involved in carrying out the exercise.
Question 5
Personal dust monitoring has been carried out on five employees, all of whom work in the same factory area where dust is released. The five employees were sampled at the same time and for equal duration. Four of the results are roughly equivalent but the fifth is significantly higher. Outline the possible reasons for this apparent discrepancy.
(10)
In outlining the reasons for the apparent discrepancy, candidates could have considered those associated with the working environment and the tasks being performed; those resulting from possible failures with the monitoring equipment and those connected with the individual employee. In considering the working environment, there could have been areas in the workplace which were not as well ventilated as others with possible problems with the local exhaust ventilation provided. As for the monitoring equipment for the individual concerned, there could have been errors in the calibration of the pump flow, in the timing of the air measurement, in the selection of the filter and in weighing the filter at the end of the exercise either because of a mis-reading or because different and possibly uncalibrated scales were used for the rogue sample. The individual, too, could have had a part to play if he had been particularly involved in the more dusty operations, had taken fewer or shorter breaks than the other operators and had not taken sufficient care with his personal hygiene and had continued to wear dusty overalls for long periods. Finally the possibility of deliberate sabotage could not be discounted.
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Question 6
(a)
(b)
Outline the following toxicological terms: (i)
LD50;
(2)
(ii)
LC50.
(2)
Outline the advantages and disadvantages of using animal studies to investigate whether a substance used at work may be carcinogenic to humans.
(6)
For part (a), to gain the two marks available in each case, candidates were expected to outline that LD50 relates to a single oral or dermal dose which when administered to a test population, is sufficient to kill 50 per cent of that population. LD50 is measured in terms of milligrams (or grams) per kilogram of body weight. LC50, on the other hand, is an inhaled concentration sufficient to kill 50 per cent of a test population in a fixed period of time (usually 4 hours) and is measured in milligrams (or grams) per litre of air. For the second part of the question, candidates should have outlined that the advantages of using animal studies include the fact that these methods avoid human exposure and hence possible human deaths and that the data can be collected more quickly and arguably more ethically than using epidemiological methods. Animals provide the best available models as they relate more closely to humans and the studies are more likely to detect carcinogenic potential than in vitro testing such as Ames tests. When considering the disadvantages, candidates could have outlined that the dose/response effect may vary in different animal species and so extrapolating data to humans may not always be reliable. Additionally, conducting animal studies can be time-consuming and expensive and there are often ethical considerations and public opinion that can make this approach more difficult to undertake. There is also the consideration that animals being treated for exposure to a particular substance may not help to identify synergistic effects that could arise in humans exposed to other substances at the same time and that the tests are carried out in laboratory conditions rather than in a workplace. There could also be difficulties with the “no observed adverse effect level” for carcinogens.
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Section B – three from five questions to be attempted
Question 7
A parcel sorting depot is experiencing a high number of manual handling related injuries. The employees handle a large number of different parcels and packages each day. (a)
(b)
(c)
Identify the different types of hazard that may be inherent in the loads being handled.
(6)
In order to reduce the level of manual handling required, the employer has decided to invest in a range of non-powered handling devices, (trolleys, trucks etc). Describe the steps that should be taken when selecting such devices and introducing their use.
(10)
Outline a range of additional control measures that could be introduced to minimise the risks associated with manual handling.
(4)
For part (a), the different types of hazard that candidates could have identified included: weight of load and the fact that the weights would be unknown; parcels may be difficult to grasp, as they are likely to be smooth with no handholds with unstable contents which are likely to move or with the centre of gravity not in the centre of the parcel; awkward shapes would be common or parcels that are too large for the handler to see over; sharp edges or corners and the possibility that the contents might spill out, some of which could be hazardous. Candidates who provided better answers for part (b) split them into two sections dealing first with the selection of the devices and then with their introduction. The selection of the handling devices requires consultation with the employees both in the selection and the trials; seeking advice from suppliers on suitability; requesting equipment on a trial basis to check whether it solves the problem without creating new ones; observing the equipment in use at other organisations; considering the requirements for maintenance; ensuring the proposed use will be within the safe working load of the device; ensuring there is sufficient room to manoeuvre; ensuring the suitability of the device in the light of the stability and surface of the terrain on which it was to be used; checking that braking controls were adequate and that the handle height was adjustable between waist and shoulder; and that the design of the equipment was such as to prevent parcels from falling off. As far as introducing the use of the devices, this would require consideration of operator training, storage when not in use, maintenance arrangements and a procedure for reporting defects; and ensuring there are a sufficient number of devices available which are readily accessible. For part (c), additional control measures that candidates might have considered were; changing the workplace layout to reduce carrying distances, twisting and stooping and avoiding lifting from floor level or above shoulder height; varying the work and its duration and pace; marking up loads with information such as the weight and the heavy end; introducing mechanical assistance such as conveyors or fork lift trucks; using team lifting where appropriate and providing training in manual handling.
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Question 8
(a) (b)
Describe the possible health effects from exposure to ionising radiation.
(5)
Outline the control measures that should be in place where persons may be exposed to ionising radiation at work.
(15)
For part (a) of this question, candidates should have described that the possible health effects from exposure to ionising radiation will depend on the type of radiation and the frequency and duration of exposure and will include nausea, vomiting, dermatitis, burns either superficially to the skin or more penetrating burns causing cell damage, cataracts, temporary or permanent infertility, decreased immunity and cancer induction. Control measures that should be in place where persons may be exposed to ionising radiation at work include limiting the time of exposure with the exclusion of particularly vulnerable groups such as young persons and pregnant women; the use of sealed sources whenever possible; increasing the distance between the radiation source and those at risk to reduce the level of exposure; using shielding between the radiation source and those likely to be exposed with the amount of shielding required dependent on the energy of the source; prohibiting eating and drinking in unsealed radioactive areas together with the need for a high standard of personal hygiene to prevent spread and the covering of all breaks in the skin with protective material; the provision, use and laundering of personal protective equipment such as gloves, lab coats and over shoes; the availability of competent advice and the provision of training and information to employees on the health risks involved and the control measures to be applied; personal monitoring by means of film badges; regular monitoring of the work area for example by means of a Geiger counter and ensuring the safe disposal of all contaminated materials.
Question 9
A company that operates hotels and health spas recognises the risks associated with the legionella bacteria. (a) (b)
In this scenario identify specific sources of potential exposure to legionella for BOTH employees and guests.
(5)
Describe the control measures that this company should implement to minimise people being exposed to legionella bacteria.
(15)
In answering part (a), candidates could have chosen from a list which includes; water storage and transfer systems (including showers and taps) where the temperature is between 20 and 45 degrees; spa baths, saunas, steam rooms and pools; water features such as fountains and cascades; fire and garden sprinkler systems; laundry rooms; and pipe work where dead legs exist and stagnation may occur. In answers to part (b), measures which should have been described include identification of a competent person for overseeing Legionella control; regular disinfection of hot water systems with biocides; annual cleaning and disinfection of calorifiers; inspection and cleaning of water storage tanks; avoiding ‘dead legs’ in transfer pipe work; maintaining hot water storage temperatures at temperatures greater than 60 degrees C and cold water below 20 degrees C; keeping shower heads and taps clean and free from scale and running showers and taps for several minutes each week in unoccupied rooms; running showers and taps immediately prior to occupation of a room; treating spa pools continuously with chlorine or biocides and cleaning them on a regular basis; avoiding the use in systems of susceptible materials such as wood or rubber; training all relevant employees in risk factors and controls; minimising biofilm formation, for example by covering water tanks and the use of chemicals, and introducing regular monitoring procedures and record keeping.
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Question 10
(a)
Explain what is meant by the terms ‘carcinogen’ and ‘mutagen’.
(b)
Describe the control measures that should be adopted when, because of the nature of the work, it is not possible to eliminate a carcinogen or substitute it with an alternative substance.
(4)
(16)
In answering part (a) of the question, candidates should have explained that a “carcinogen” is a substance that may cause cancer or bring about changes in the make up of cells while a “mutagen” causes or increases the rate of mutation in DNA and may affect subsequent generations. For part (b), specific control measures that should be adopted when it is not possible to eliminate a carcinogen or substitute it with an alternative substance include reducing exposure to a level as low as reasonably practicable by minimising quantities used and/or changing the physical form; the 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. It would also be necessary to provide 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. Materials would have to be correctly labelled 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 11
(a)
Describe the structure of the skin and how hazardous substances may enter the body by this route.
(6)
(b)
Explain how contact (primary) dermatitis can occur.
(4)
(c)
A number of employees working in a hair salon have reported problems of skin irritation on their hands, which for at least one employee has been diagnosed as contact dermatitis. Advise the salon manager on the likely causes and the steps that could be taken to try to overcome these instances of contact dermatitis.
(10)
For part (a) of the question, candidates should have described how the skin has an outer layer, the epidermis, consisting of dead cells that are continually shed and provide protection for the inner layer, the dermis. The dermis comprises living cells and contains blood capillaries, nerve endings and sweat glands. It is partially permeable and substances that are soluble in water or fat may migrate or be absorbed through the skin and enter the blood stream. Hazardous substances may also enter via cuts or abrasions or by injection.
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A good answer to the second part of the question would have explained how contact dermatitis occurs following prolonged or repeated exposure to certain substances which de-fat or degrease the skin, destroying the natural oils and leaving it dry, cracked and inflamed. The dermatitis occurs at the point of contact and skin normally recovers following cessation of exposure though repeated instances of contact dermatitis may lead to chronic conditions. In answering part (c), candidates were asked to provide advice on the likely causes of contact dermatitis in employees in a hair salon and the precautionary measures that should be taken. The causes of dermatitis amongst hairdressers include exposure to irritant substances such as bleaches and dyes, prolonged contact with water and detergents, the removal of natural oils from the skin and the possibility of sensitisation to one or more of the materials used. There may also be contributory factors such as individual susceptibility, the concentration and potency of the substances in use, the frequency and duration of exposure to the substances, damaged skin, poor personal standards of hygiene and a failure to protect hands by using barrier creams and gloves. Steps that could be taken to reduce the incidence of dermatitis would include a clear skin care policy; the identification of susceptible persons during recruitment procedures; ensuring safety data sheets are available for all products used; the elimination or substitution of allergic products; job rotation to reduce individual involvement in wet work, perms and the application of dyes; the provision and use of disposable gloves when using shampoos, bleaches or colouring agents; the provision of training and information with particular reference to standards of personal hygiene such as washing and drying hands thoroughly to remove residual products after use, the application of skin care creams to restore moisture to the skin and the correct method of removing gloves to avoid contaminating hands; and encouraging the staff to report problems with their skin as soon as they are noticed.
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