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 2009
Comments on individual questions
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fax: 0116 282 4000
email: [email protected]
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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 2009
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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. Common pitfalls 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.
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.
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.
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.
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.
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.
Candidates should also be aware that Examiners cannot award marks if handwriting is illegible.
UNIT IB – International control of hazardous agents in the workplace
Section A – all questions compulsory Question 1
Construction workers regularly use cement. Several of the long term workers and one of the new recruits have complained about red and sore skin on their hands. (a)
Explain the possible reasons for the symptoms they are experiencing.
Outline control measures that could be used to minimise these symptoms in this situation.
The symptoms suggest that the workers are suffering from dermatitis caused by a chronic or repeated exposure to an irritant or irritants. Cement is a known irritant which can cause allergic contact dermatitis through contact with a sensitiser chromium compound impurities in the material - that produces an over reaction from the body’s immune system. Sensitisation can occur on first contact such as with the new recruit or after some time in the case of the long term workers. The effect of contact with the irritant de-fats and degreases the skin and overcomes the skin’s own defence and repair systems. Friction and abrasion from general floor laying will not help the condition. For part (b), candidates could have outlined control measures that could be used to minimise the symptoms such as using a non-cement based compound, for example, a polymeric compound; wearing gloves to protect the skin and minimising contact by the use of hand tools; providing washing facilities so that contaminants can be washed from the skin as soon as possible with the hands dried thoroughly after washing; using pre-work and after work moisturising creams to replenish the natural oils in the skin; giving information to the workers on the importance of carrying out their own skin inspections and encouraging them to report any problems with their skin; and arranging for supervisors to carry out regular skin inspections of the workers. This question was not very well answered. Some candidates did not identify that the dermatitis was caused through contact with the cement while others described the disease.
In a manufacturing process, operators use a range of solvents. Describe a monitoring strategy that could be used to measure the exposure of the operators to solvent vapours.
A logical and structured approach to part (a) would have referred to the three stage approach in HSG 173 (initial, basic and detailed), taken each stage in turn and described the circumstances in which it would be appropriate to use that type of monitoring, and the methods and equipment that could be used. The first stage would take the form of an initial appraisal with the objective of determining if and to what extent more detailed monitoring of workers’ exposure would be required. It is basically an exercise to gather information to determine who/where/what/when to monitor and for how long, ensuring that any sampling is representative. Data sources such as SDSs would obviously be useful here.. Within the strategy a number of measuring methods could be used ranging from the use of stain tubes to direct reading instruments to active sampling. It might be necessary to take samples either on a personal or static basis, and either for the short or long term with the samples being analysed using a method such as gas chromatography. References to appropriate standards (such as exposure limits or methods) were also relevant. Finally, biological monitoring could be used to measure what has actually been taken into the body rather than the airborne concentration. There were many candidates who did not seem to appreciate that the question required a description of a monitoring strategy and wrote instead of the control measures that should be applied and the health effects of exposure to solvents.
A catalogue distribution company employs drivers, warehouse staff and office staff to process telephone and internet orders. Identify the functions of the distribution company’s occupational health department when: (a)
recruiting new workers;
a worker returns to work after ill-health.
During the recruitment of new workers, the occupational health department would have an important part to play in carrying out screening of the applicants and reviewing their health history so that they might be in a position to advise management on their suitability for employment. In particular they would need to check the fitness and ability of potential warehouse staff to undertake manual handling tasks, check the eyesight of applicants for positions as drivers whether of road or internal vehicles and also screen them for evidence of the possible mis-use of alcohol or other substances. Additionally it would be important to carry out eyesight tests on those who would be employed in the office to use display screen equipment. Other examples, related to particular workers, were also accepted. As for those workers preparing to return to work after a period of ill-health, an assessment of their current health condition would enable recommendations to be made to management on whether the return should be phased or whether the worker should be redeployed on other or lighter duties. This would necessitate liaison with the worker’s medical practitioner and where necessary arranging for counselling and rehabilitation treatment or even providing this in house. Some workers may also need to be monitored on an on-going basis.
No specialist knowledge was needed to answer this question and the majority of candidates did well though a few did not seem to realise that the first part dealt with the recruitment of new workers and wrote on what functions the occupational health department might have in dealing with all the workers in the organisation.
According to current veterinary and medical opinion the bacterium E. coli O157 should be assumed to be carried by all ruminants (cattle, sheep, goats and deer). In addition, this bacterium can exist for long periods of time outside of the animal (in soil and faeces). (a)
Identify ways in which school children visiting a farm might be exposed to E. coli O157 bacterium.
Explain a range of practical control measures that should be put in place in order to reduce this risk of exposure.
In answering part (a), candidates had first to recognise that the bacteria was transmissible through hand to mouth contact. With that understood, there should have been no difficulty either in suggesting how children on a visit to an open farm might be exposed to the bacteria or in explaining control measures that should be put in place. The children’s hands could be contaminated by touching animals, for example in petting areas or in bottle feeding; touching surfaces contaminated by faeces such as gates and fences and coming into contact with contaminated footwear during its removal. The transfer of the bacteria to the mouth could take place during eating or drinking before hands had been thoroughly washed or from putting fingers near or in the mouth for any other purpose - as young children often do. For part (b), there was a range of control measures that could be put in place. It would be important before the visit took place to brief schools of the precautions to be observed so that the children could be advised of what they should and should not do once they arrived at the farm. On the farm, contact with animals should be restricted to specified areas and arrangements put in place to clean, disinfect and remove faeces from these areas on a regular basis. Visitor contact with animals in other areas should be prevented. Hand washing facilities should be provided, ideally placed at the exits from contact areas and before entrance to areas set aside for taking refreshment and it would be sensible for children to be advised on thorough hand washing techniques at the start of the visit. The animal areas should be segregated from areas set aside for eating and signs warning of the risks of contamination and the precautions to be taken placed in strategic positions. Finally the farm management should ensure that there is an adequate number of staff on duty to supervise and advise visitors in the contact areas. This question was generally well answered though a few candidates did not take a practical view and wrote about stopping visits to the farm altogether and taking children to a museum instead.
The figure below shows an audiogram for an adult worker.
Explain what is meant by ‘threshold shift’.
Outline the significance of the shape of the audiogram.
Outline the benefits AND limitations of audiometry as part of a hearing conservation programme.
In answering part (a) of the question, candidates should have explained that threshold shift is the difference between the hearing threshold of a subject and the hearing threshold of an average young adult with healthy, disease free ears. There were many incorrect definitions given for this part of the question. Good answers to part (b), but these were few in number, would have outlined that the shape of the audiogram with a 4 KHz notch is typical of noise induced hearing loss. In outlining the benefits of audiometry for part (c), candidates were expected to identify: that it provides some evidence of the effectiveness of a hearing conservation programme; that pre-employment or baseline screening identifies those with existing problems; that it enables identification of susceptible individuals and early signs of hearing loss; it provides an opportunity to inform workers about noise induced hearing loss and methods of prevention; and it may lead to reduced insurance premiums and provides information that can be used to defend civil claims. Its limitations are: that it is not preventive since some damage has to occur before the problem is identified; it may encourage civil claims; it diverts resources away from noise control; it is subject to inaccuracy, because of operator competence or the time of day and abuse; it detects hearing loss but not the source of noise induced hearing loss and would experience difficulty in establishing trends if the workforce is transient. While candidates did gain some marks in answering this part of the question, examiners were not confident that the majority had a sound grasp of audiometry and its benefits and limitations.
Outline the factors that should be considered in relation to the job, the individual and the work environment when carrying out an assessment of ergonomic risks in a workplace.
The logical way to answer this question was to use the structure suggested by considering ergonomic factors relating to the job, the individual and the work environment. Job factors relating to ergonomics include consideration of the demands of the task, such as the duration, repetition, the work rate and the opportunity to take breaks. The equipment that a person uses as part of the job can affect the ergonomic risks in a number of ways such as the amount of force or effort required to operate the equipment as well as the design and lay out of the controls. The postures that are adopted when carrying out the job, whether or not equipment is involved, can increase the risks, especially if these postures are awkward or involve frequent twisting, stretching or prolonged stooping. When considering factors relating to the individual, candidates were expected to identify that the stature, shape, strength, and general fitness and mobility of the individual are important as are factors such as gender, age and sensory abilities such as hearing and vision. An individual’s mental capabilities, level of experience, knowledge and level of training should also be taken into account. Finally, the physical aspects of the working environment, such as lighting, temperature, noise, humidity, space and floor conditions also need to be considered as part of any ergonomic assessment. Many candidates provided good answers for this question though there were some who perhaps did not read the question with sufficient care and described how a risk assessment for the use of display screen equipment should be carried out.
Section B – three from five questions to be attempted Question 7
A new leisure centre is planning to install ultra-violet (UV) tanning equipment. The equipment uses UV sources with a higher intensity than normal sunlight to accelerate tanning. (a)
Outline control measures that should be put in place for BOTH workers and customers for the safe operation of this facility.
Identify BOTH the acute and chronic effects that could result from exposure to UV radiation.
Outline TWO other examples of occupational exposure to UV radiation.
Control measures that should be put in place both for workers and customers would initially entail taking into account the customer’s risk factors such as skin type, medication, age, pregnancy and family skin cancer history and recommending and restricting their time of exposure. Workers would need to be made aware of the risks of exposure to UV radiation and then instructed in the operation of the equipment including the safety controls and features fitted such as the timer and emergency alarm and the importance of carrying out pre-user checks and cleaning between each customer. Dealing with the customers would also be important and workers would need to advise them on the risks associated with UV exposure, the recommended duration/frequency of their exposure and the precautions to be taken such as wearing goggles and sun screen products. Other control measures that should be put in place include the screening or enclosure of the tanning equipment, the siting of worker workstations away from stray UV radiation, the provision of suitable goggles and ensuring their use, carrying out regular maintenance on the equipment such as changing tubes, maintaining records of customer exposure and displaying safety advice to customers. For part (b), the acute effects that could arise from exposure to UV radiation are erythma or sun burn and eye irritation or arc eye. The chronic effects could well be premature skin ageing, cataracts and skin cancer. For part (c), candidates could have chosen examples of occupational exposure to UV radiation such as construction or agricultural workers from exposure to the sun; welders undertaking arc welding; dentists using UV light sources for dental treatments; laboratory workers using UV light sources to sterilise equipment; workers undertaking research using high powered lasers and printers using UV radiation to cure inks and lacquers. Answers to parts (a) and (b) of the question varied from good to poor. Those who did not do so well seemed to know little about UV radiation, its health effects or how tanning equipment worked in practice. However standards improved for the last part of the question with most able to provide two other examples of occupational exposure to UV radiation.
Workers can be monitored to estimate their individual exposure to toxic and corrosive substances. (a)
Describe the meaning of the following terms: (i)
workplace atmospheric monitoring;
Outline the advantages and disadvantages of biological monitoring compared with atmospheric monitoring.
In answering part (a) of the question, candidates were expected to describe: that toxic relates to substances which cause harm to living tissue, specifically that at low levels they can cause death or acute or chronic damage to health when inhaled, ingested or absorbed through the skin; that corrosive substances can rapidly destroy living tissue if inhaled, ingested or splashed on the skin or eyes; that atmospheric monitoring is the monitoring of airborne workplace contaminants, usually by personal sampling though on occasions static monitoring can be used, is based on the inhalation route and its measurements are averaged over a time scale to give a time weighted average; that biological monitoring is a form of health surveillance concerned with the measurement or assessment of hazardous substances or their metabolites in for example, blood, urine or expired air in order to prevent health impairment; and that it takes account of uptake by all routes including skin absorption and ingestion and not only by inhalation. In answering part (b) on the advantages and disadvantages of biological monitoring (BM) as opposed to atmospheric monitoring (AM), candidates were expected to outline that the advantages of BM are that it measures uptake of a substance by all routes of entry, takes account of individual variation when assessing dose, and monitors both occupational and non-occupational exposure while AM measures only the atmospheric level. BM is particularly relevant where there is a high dependency on personal protective equipment. However, there are relatively few techniques and standards available for BM in comparison with the number available for AM. BM may involve invasive techniques, can cause confidentially issues and also may raise ethical issues involved in retrospective monitoring particularly with suspected carcinogens. Real time monitoring is possible with AM but more difficult with BM which is better at pinpointing sources of exposure. This was not a popular question and those who attempted it did not meet with much success. Many could not provide a meaning for toxic and corrosive substances and did not seem to realise that part (b) required a comparison between the two types of monitoring.
(i) (ii) (iii)
Identify SIX factors that can affect the thermal comfort of an individual.
Outline the role of heat indices when assessing a thermal environment.
Give an example of a heat index AND identify the parameters that contribute to this index.
Catering staff prepare chilled meals for reheating. A significant part of their working day is spent in an area where the ambient temperature is between 3° and 5°C. Describe the control measures that could be used to minimise the risks associated with working in this cold environment.
In answering part (a) (i) of the question, candidates could have identified factors such as air temperature, radiant temperature, humidity, air velocity, metabolic or activity rate, clothing, sweat rate, duration of exposure, age, weight and fitness and the degree of acclimatisation. Heat indices are an objective measure of a thermal environment and provide a single number representation of several different parameters. They give an indication of the severity of a thermal environment and can be used in comparisons to recommend standards as part of a risk assessment. In giving an example of a heat index and its contributing parameters, candidates could have chosen from effective temperature – using the parameters of wet bulb temperature, dry bulb temperature, air velocity; corrected effective temperature – wet bulb temperature, globe temperature, air velocity; predicted 4 hour sweat rate – dry bulb temperature, globe temperature, air velocity, humidity, work rate and clothing; wind chill index – dry bulb temperature and air velocity; and WBGT – wet bulb temperature, dry bulb temperature, globe temperature. For part (b) control measures that could have been described included: carrying out pre-employment examinations to identify susceptible individuals; allowing new workers to become gradually acclimatised to the working environment; providing thermal clothing such as insulated suits or jackets with gloves, head covering and insulated safety footwear with accommodation and drying facilities for the clothing; minimising the amount of effort needed to carry out the work to avoid sweating; providing insulated mats for workers to stand on and minimising the amount of time they spend standing or sitting still; restricting time spent in the cold store by arranging job rotation and providing hot drinks and a warm rest room; introducing precautions to avoid workers being locked in the cold store by ensuring doors can be opened from the inside and by providing alarms; carrying out regular health surveillance and providing training and information for the workers on the risks involved in the work and the precautions to be taken. Very few attempted this question but they did gain marks for part (a)(i) but less in parts(a)(ii) and (iii). For part (c), there seemed to be a difficulty in understanding the scenario described and many totally impracticable control measures were suggested. Risk assessment is not a control measure but it was suggested by practically everyone who attempted the question.
Hospital nurses are at risk from work-related violence when they are required to visit patients in their own homes. (a)
Outline a strategy that the hospital management should have in place in order to manage work-related violence.
Describe a range of practical measures that the nurses can take to minimise the risk of violence when making visits to patients.
The key elements of a strategy that the hospital management should have in place to manage work related violence (WRV) include the preparation of a written policy defining the term, stating the management’s zero tolerance attitude to violence to their staff and indicating their support for legal action should this occur; the identification of groups particularly at risk; the provision of adequate resources to control and minimise the risks associated with WRV; the introduction of procedures for reporting, recording and investigating incidents of violence; the identification of workers with particular responsibilities for managing WRV such as carrying out the risk assessments, receiving reports of instances of violence and monitoring compliance with control measures introduced as a result of the assessments made; the provision of training to workers on how to deal with situations where violence might occur; liaison with other agencies (to share information) on individuals relevant to; and mechanisms to support victims, such as the provision of counselling and assurance of confidentiality.. For part (b), there are many practical measures that nurses might take to minimise the risk of violence including: informing colleagues of the location and time of visits with appointments being made for the hours of daylight and leaving a written record in the office with the anticipated time of return; checking out the history of the patient prior to the visit for violent marker flags on the records and dependent on the level of risk, either visiting in pairs or requiring the patient to come to the hospital (where the risk is high); carrying a mobile phone, radio or personal alarm and agreeing a code word when calling for assistance; wearing appropriate clothing and refraining from wearing or carrying items of value; planning the journey route to minimise risk and parking the vehicle in a way and in a location to facilitate a speedy exit if required; and at the visit behaving in such a way that confrontation is avoided. Candidates had difficulty in differentiating between a strategy and practical control measures. Many described measures to be taken in hospital premises seeming to misunderstand that the question was concerned with visits to patients in their own homes.
Workers cutting and finishing stone are exposed to stone dust. Stone dust has been assigned a legally enforceable Occupational Exposure Limit (OEL). (a)
Give the meaning of ‘Occupational Exposure Limit’ (OEL).
Explain the factors to be considered when undertaking a suitable and sufficient assessment of the risks from exposure to stone dust.
Outline a suitable range of control measures that could reduce the risk to these workers from exposure to stone dust.
For part (a), candidates were expected to understand that an Occupational Exposure Limit (OEL), is the maximum concentration of a substance to which workers may be exposed by inhalation. The concentration is measured in mg/m³ or ppm and is averaged over a reference period, either long term over a period of eight hours intended to control effects by restricting the total intake by inhalation over one or more work shifts, or short term, usually fifteen minutes, to control effects that may be seen after a brief exposure. For the control of stone dust to be adequate the OEL should not be exceeded and the principles of good hygiene practice should be followed. In undertaking an assessment of the risks from exposure to stone dust, factors to be considered include the health effects of the dust such as irritation to the skin, eyes and respiratory tract (physical structure such as crystalline or amorphous may also have a bearing on longer term health effects); the number of persons exposed, the level, duration and frequency of their exposure and the susceptibility of individuals such as to asthma; the routes of entry of the dust such as through inhalation or ingestion; the particle size of the dust which will determine how far into the body the dust will pass; the way in which the work is carried out whether by hand or power tool; the level and effectiveness of existing control measures and results from the monitoring of airborne contaminants and their comparison with the OEL together with the results of health surveillance. As for suitable control measures, for operations carried out in a workshop, the use of local exhaust ventilation would be required but for outside work damping down would be the measure that would have to be used. Controls to be used in both situations include the use of cutting tools with in–built extraction or a damping spray; the provision and use of respiratory protective equipment (RPE) which should be comfortable to wear for extended periods of use, and compatible with other personal protective equipment such as eye and hearing protection, gloves and overalls; and facilities both for washing, changing and for the laundering and storage of overalls. RPE users should also be subject to face-fit testing and the RPE itself properly cleaned and stored when not in use. Training for workers on hazards and precautions was also relevant. Some definitions of OEL submitted in answer to part (a) were particularly vague and there was little understanding of the factors to be considered when carrying out an assessment of the risks from exposure to stone dust in part (b).
The National Examination Board in Occupational Safety and Health Dominus Way Meridian Business Park Leicester LE19 1QW telephone +44 (0)116 2634700 fax +44 (0)116 2824000 email [email protected]