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NIOSH Safety and Health Officer (SHO) - Occupational Health (Malaysia) study materials
NIOSH Safety and Health Officer (SHO) - Occupational Health (Malaysia) study resources

NIOSH Safety and Health Officer (SHO) - Occupational Health (Malaysia) practice questions

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Question 1Occupational Health

Under Malaysia's Occupational Safety and Health (Use and Standards of Exposure of Chemicals Hazardous to Health) Regulations 2000, what is the primary duty of an employer before employees work with a chemical hazardous to health?

  1. Conduct a chemical health risk assessment and keep it updated Correct answer.
  2. Register the chemical with the Department of Environment
  3. Provide annual chest X-rays for all staff
  4. Notify the local municipal council of the chemical inventory

Explanation

The USECHH Regulations 2000 require the employer to conduct a chemical health risk assessment (CHRA) by a competent assessor before exposure occurs, and to review it periodically or when there is a change in process. The CHRA identifies hazards, exposure routes and control needs, forming the basis for all subsequent control measures.

Question 2Occupational Health

An SHO is reviewing noise exposure data at a metal stamping plant. Which action is required when the daily noise exposure level is found to exceed 85 dB(A)?

  1. Conduct audiometric testing and provide hearing protection, with exposure controls where practicable Correct answer.
  2. Rotate workers so each stays under eight hours regardless of level
  3. Only distribute hearing protectors and take no other action
  4. Wait until exposure exceeds 90 dB(A) before any action

Explanation

The Factories and Machinery (Noise Exposure) Regulations 1989 set 90 dB(A) as the permissible exposure limit and 85 dB(A) as the action level requiring audiometric testing and provision of hearing protectors. Exposure should be reduced by engineering and administrative controls so far as is practicable, with protection as the last barrier.

Question 3Occupational Health

Which agency administers the Occupational Safety and Health Act 1994 and the associated regulations in Malaysia?

  1. Ministry of Health
  2. Department of Environment
  3. Department of Occupational Safety and Health Correct answer.
  4. National Institute of Occupational Safety and Health

Explanation

The Department of Occupational Safety and Health (DOSH), under the Ministry of Human Resources, enforces the OSH Act 1994 and its subsidiary regulations. NIOSH Malaysia is a training and research institute, not the enforcement authority.

Question 4Occupational Health

An employer's general duties under section 15 of the OSH Act 1994 require the employer to ensure safety and health of employees at work so far as is practicable. Which statement best describes the term 'practicable'?

  1. Only measures that are explicitly stated in regulations
  2. Actions agreed through collective bargaining with the union
  3. Reasonable and feasible in light of current knowledge, cost and risk Correct answer.
  4. Whatever is physically possible regardless of cost

Explanation

In Malaysian OSH law 'practicable' means reasonably practicable, weighing the severity of risk against the cost, time and difficulty of the measure. It is not an absolute standard requiring every conceivable step regardless of cost.

Question 5Occupational Health

Which of the following is the correct hierarchy of control for occupational hazards, from most to least preferred?

  1. Personal protective equipment, administrative controls, engineering controls, elimination
  2. Administrative controls, elimination, personal protective equipment, engineering controls
  3. Elimination, engineering controls, administrative controls, personal protective equipment Correct answer.
  4. Engineering controls, personal protective equipment, elimination, administrative controls

Explanation

Control measures are ranked starting with eliminating the hazard, then substituting or engineering out exposure, then administrative controls, with PPE as the last line of defence. This hierarchy reflects the principle that controls not dependent on human behaviour are more reliable.

Question 6Occupational Health

In a chemical plant, an SHO finds that workers handle a volatile solvent in an open tray. Which control measure should be prioritised according to the hierarchy of control?

  1. Install local exhaust ventilation or enclose the process Correct answer.
  2. Shorten the shift to four hours
  3. Issue respirators to all operators
  4. Post warning signs at the tray

Explanation

Engineering controls such as local exhaust ventilation or process enclosure remove or capture the contaminant at source, protecting all workers independently of behaviour. PPE and administrative measures are secondary and depend on consistent use and supervision.

Question 7Occupational Health

Which document must an employer prepare under the OSH Act 1994 to describe the organisation's safety and health policy, responsibilities and arrangements?

  1. A written safety and health policy Correct answer.
  2. A noise exposure map
  3. A chemical register
  4. A fire certificate

Explanation

Section 16 of the OSH Act 1994 requires an employer with five or more employees to prepare and revise a written statement of general policy on safety and health, together with the organisation and arrangements for implementing it.

Question 8Occupational Health

Which body is established under the OSH Act 1994 to formulate and coordinate safety and health policy at national level?

  1. Construction Industry Development Board
  2. National Council for Occupational Safety and Health Correct answer.
  3. DOSH Enforcement Board
  4. Malaysian Trades Union Congress

Explanation

The National Council for Occupational Safety and Health (NCOSH), established under section 8 of the OSH Act 1994, advises the Minister and coordinates national OSH policy. It brings together government, employers and workers.

Question 9Occupational Health

An SHO is designing a health surveillance programme for workers exposed to lead. Which best describes the purpose of medical surveillance in occupational health?

  1. To satisfy insurance requirements only
  2. To detect early adverse health effects and confirm control measures are adequate Correct answer.
  3. To replace environmental monitoring entirely
  4. To screen out workers with pre-existing conditions from employment

Explanation

Medical surveillance aims to detect early biological effects of exposure, verify that controls are effective, and trigger intervention before harm progresses. It complements but does not replace workplace exposure monitoring.

Question 10Occupational Health

Which of the following is a recognised occupational lung disease associated with inhalation of respirable crystalline silica?

  1. Silicosis Correct answer.
  2. Byssinosis
  3. Bagassosis
  4. Farmer's lung

Explanation

Silicosis results from inhaling respirable crystalline silica, causing fibrotic lung nodules, and is associated with mining, quarrying, foundry and construction work. It is a classic pneumoconiosis with no specific cure, making prevention through dust control essential.

Question 11Occupational Health

Which biological monitoring method is appropriate for assessing recent exposure to toluene in a glue-spraying operation?

  1. Serum cholinesterase
  2. Blood lead level
  3. Urinary delta-aminolevulinic acid
  4. Urinary hippuric acid or o-cresol Correct answer.

Explanation

Toluene is metabolised to hippuric acid and o-cresol, which are measured in urine as indicators of recent exposure. Blood lead and delta-aminolevulinic acid relate to lead exposure, while cholinesterase monitoring relates to organophosphate pesticides.

Question 12Occupational Health

Which of the following is a key element of a permit-to-work system for confined space entry?

  1. Continuous entry without re-testing after a break
  2. Atmospheric testing and a signed written permit before entry Correct answer.
  3. Verbal authorisation from a colleague
  4. Entry without standby personnel if the task is short

Explanation

A permit-to-work system requires pre-entry atmospheric testing, isolation, a written and signed authorisation, and a competent standby person. The permit documents that controls are in place and must be revalidated after interruptions.

Question 13Occupational Health

Which health effect is most characteristic of chronic whole-body vibration exposure from driving heavy machinery?

  1. Vibration white finger
  2. Carpal tunnel syndrome only
  3. Low back pain and spinal degeneration Correct answer.
  4. Noise-induced hearing loss

Explanation

Whole-body vibration transmitted through the seat affects the lumbar spine, contributing to low back pain and degenerative changes. Hand-arm vibration from powered tools causes vibration white finger and is a separate exposure route.

Question 14Occupational Health

Which of the following best describes the purpose of a health risk assessment for manual handling tasks?

  1. To decide which workers are too weak for the job
  2. To calculate insurance premiums for the employer
  3. To determine the disciplinary consequences of poor lifting technique
  4. To identify and evaluate factors that may cause musculoskeletal injury and prioritise controls Correct answer.

Explanation

Manual handling risk assessment evaluates load, posture, frequency, environment and individual factors to identify musculoskeletal injury risk and guide proportionate control measures. It informs redesign of the task rather than blaming the worker.

Question 15Occupational Health

Which occupational exposure limit concept refers to the airborne concentration of a substance averaged over an eight-hour working day?

  1. Time-weighted average Correct answer.
  2. Immediately dangerous to life or health
  3. Ceiling limit
  4. Short-term exposure limit

Explanation

The time-weighted average (TWA) expresses average exposure over a reference period such as eight hours, allowing variable exposure patterns to be compared with a limit. Short-term and ceiling limits address brief peak exposures.

Question 16Occupational Health

An SHO is investigating an outbreak of dermatitis among workers handling cutting fluids. Which preventive measure is most appropriate at the source?

  1. Rotate staff between machines
  2. Instruct workers to wash hands more frequently with solvent
  3. Introduce enclosed or automated fluid delivery and proper fluid management Correct answer.
  4. Provide barrier cream as the primary control

Explanation

Engineering controls such as enclosure and automated delivery reduce skin contact with metalworking fluids at source, supported by fluid maintenance to limit microbial growth. Skin care and PPE support but do not replace source controls.

Question 17Occupational Health

Which statement correctly describes the role of a Safety and Health Committee under the OSH Act 1994?

  1. It replaces the need for a safety and health officer
  2. It assists in identifying unsafe conditions and reviewing safety measures Correct answer.
  3. It takes over the employer's statutory duties
  4. It issues legally binding improvement notices

Explanation

A safety and health committee, required where a specified number of employees are employed, reviews safety and health measures, investigates incidents and promotes cooperation between employer and workers. It advises and assists but does not assume the employer's legal duties.

Question 18Occupational Health

An employer introduces a new chemical process. Under the USECHH Regulations 2000, when must the chemical health risk assessment be reviewed?

  1. Only when requested by the workers
  2. Only after a reported accident
  3. Every ten years regardless of change
  4. When there is a change in process or new information indicates the assessment is no longer valid Correct answer.

Explanation

The CHRA must be reviewed when there is a change in work process, equipment or chemical, when new hazard information becomes available, or when monitoring or health data indicate the controls are inadequate. Fixed intervals alone do not satisfy the duty.

Question 19Occupational Health

Which of the following best describes the purpose of workplace air monitoring for a hazardous chemical?

  1. To identify the chemical's fire properties
  2. To replace the need for medical surveillance
  3. To determine individual worker susceptibility to the chemical
  4. To estimate inhalation exposure against exposure limits and evaluate control effectiveness Correct answer.

Explanation

Air monitoring measures airborne concentrations in the breathing zone or workplace to compare against exposure limits and verify that controls work. It does not measure individual susceptibility or fire properties.

Question 20Occupational Health

An SHO is advising on heat stress for outdoor workers. Which combination of measures best reflects good practice?

  1. Providing salt tablets only
  2. Requiring workers to wear impermeable suits
  3. Increasing work pace to shorten exposure duration
  4. Acclimatisation, fluid provision, scheduled rest and shade Correct answer.

Explanation

Heat stress prevention combines acclimatisation, adequate drinking water, scheduled rest breaks and shaded or cooled rest areas, with monitoring for heat illness symptoms. These measures address fluid loss and heat load without relying on a single intervention.

Question 21Occupational Health

Which of the following is a correctly stated purpose of personal protective equipment in occupational health practice?

  1. It is the preferred control for all hazards
  2. It removes the need for exposure monitoring
  3. It eliminates the hazard at source
  4. It is a last line of defence used when other controls cannot adequately reduce exposure Correct answer.

Explanation

PPE is used as a last line of defence when elimination, substitution and engineering or administrative controls cannot adequately reduce exposure. Its effectiveness depends on correct selection, fit, training and consistent use, so monitoring and supervision remain necessary.

Question 22Occupational Health

Which condition is recognised as an occupational cancer associated with asbestos exposure?

  1. Mesothelioma Correct answer.
  2. Byssinosis
  3. Silicosis
  4. Asthma

Explanation

Mesothelioma is a malignant tumour of the pleura or peritoneum strongly associated with asbestos exposure, often with a long latency of decades. Silicosis and byssinosis are non-malignant dust diseases, and asthma is a reversible airways disorder.

Question 23Occupational Health

An SHO is investigating a cluster of needlestick injuries among hospital staff. Which control measure should be prioritised?

  1. Reducing staffing levels on the ward
  2. Providing gloves only
  3. Introducing safety-engineered sharps devices and safe disposal systems Correct answer.
  4. Training staff to recap needles carefully

Explanation

Safety-engineered devices and effective sharps disposal systems reduce injury at source and are more reliable than behavioural measures. Recapping is a high-risk practice that should be eliminated rather than trained as a technique.

Question 24Occupational Health

Which of the following best describes the principle of 'fit testing' for respiratory protective equipment?

  1. Verifying that the selected respirator forms an adequate seal on the individual wearer Correct answer.
  2. Measuring the airborne concentration of the contaminant
  3. Checking that the filter is within its expiry date
  4. Confirming the respirator meets the purchase specification

Explanation

Fit testing checks that a specific respirator model and size achieves an adequate seal on an individual's face, because facial features vary. It is distinct from filter checks, exposure measurement and equipment specification.

Question 25Occupational Health

Which of the following is the most appropriate first action when an SHO identifies a serious and imminent danger to workers?

  1. Take immediate action to stop the work and remove workers from danger Correct answer.
  2. Continue work while arranging a risk assessment
  3. Document the finding and raise it at the next committee meeting
  4. Wait for DOSH to issue a prohibition notice

Explanation

Where there is serious and imminent danger, the priority is to stop the activity and move people to safety immediately, then notify and address the underlying cause. Administrative steps such as committee discussion follow the protective action.

Question 26Occupational Health

Under the Occupational Safety and Health Act 1994, which general duty does an employer owe to employees regarding occupational health?

  1. To guarantee that no employee will ever develop an occupational disease
  2. To compensate employees for all illnesses regardless of work-relatedness
  3. To provide, so far as is practicable, a working environment that is safe and without risks to health Correct answer.
  4. To delegate all health responsibilities to the employees themselves

Explanation

Section 15 of the OSH Act 1994 requires every employer to ensure, so far as is practicable, the safety, health and welfare of employees at work. The duty is qualified by practicability, which balances risk against cost and effort, and it is not an absolute guarantee against disease. Compensation is dealt with under separate social security legislation, not this general duty.

Question 27Occupational Health

Which occupational health service is an employer required to provide under the OSH Act 1994 for workers exposed to health hazards?

  1. A health surveillance programme appropriate to the health risk Correct answer.
  2. A private gym membership for shift workers
  3. Free annual influenza vaccination for all staff
  4. Routine whole-body MRI screening every year

Explanation

The OSH Act 1994 and its subsidiary regulations require health surveillance where workers are exposed to specified health hazards, so that early signs of work-related ill health can be detected. The surveillance must be relevant to the hazard and carried out by a competent occupational health professional. General wellness benefits are not a legal substitute for hazard-specific surveillance.

Question 28Occupational Health

Which of the following is the primary purpose of an occupational health risk assessment?

  1. To assign blame to workers who fail to follow procedures
  2. To satisfy insurers that premiums can be reduced
  3. To identify hazards and decide on proportionate control measures Correct answer.
  4. To replace the need for workplace inspections

Explanation

An occupational health risk assessment systematically identifies health hazards, evaluates who might be harmed and how, and determines the control measures needed. It is a proactive planning tool, not a fault-finding or insurance exercise. It complements, rather than replaces, inspections and monitoring.

Question 29Occupational Health

In the hierarchy of control for occupational health hazards, which control measure is ranked highest?

  1. Providing personal protective equipment
  2. Posting warning signs at the workplace
  3. Rotating workers to reduce exposure duration
  4. Eliminating the hazard at source Correct answer.

Explanation

The hierarchy of control places elimination of the hazard at the top because it removes the risk entirely and does not depend on worker behaviour. Engineering and administrative controls follow, with PPE as the last line of defence. Warning signs and worker rotation are lower-order measures.

Question 30Occupational Health

Which type of occupational health hazard is noise most likely to cause?

  1. Lead poisoning
  2. Noise-induced hearing loss Correct answer.
  3. Contact dermatitis
  4. Occupational asthma

Explanation

Noise is a physical hazard whose principal health effect is noise-induced hearing loss, initially at high frequencies and progressing with continued exposure. Occupational asthma and dermatitis are associated with chemical or biological agents, and lead poisoning with heavy metal exposure. Hearing loss from noise is irreversible, so prevention through engineering controls and hearing protection is essential.

Question 31Occupational Health

Which of the following is an example of a biological hazard in the workplace?

  1. Exposure to solvent vapour in a paint shop
  2. Exposure to ionising radiation from an X-ray machine
  3. Exposure to blood-borne viruses through sharps injuries Correct answer.
  4. Exposure to whole-body vibration from a forklift

Explanation

Biological hazards include bacteria, viruses, fungi and other microorganisms that can cause infection or allergic reactions. Blood-borne viruses transmitted through sharps injuries are a classic biological hazard in healthcare. Radiation, solvents and vibration are physical or chemical hazards.

Question 32Occupational Health

Which of the following best describes the purpose of personal protective equipment (PPE) in occupational health?

  1. To replace engineering controls entirely
  2. To provide a barrier between the worker and the hazard when other controls are insufficient Correct answer.
  3. To eliminate the hazard from the workplace
  4. To serve as the first choice of control for all hazards

Explanation

PPE provides a physical barrier that reduces worker exposure when hazards cannot be adequately controlled by elimination, substitution or engineering measures. It is the last line of defence because its effectiveness depends on fit, correct use and maintenance. PPE does not remove the hazard and should not be the default first choice.

Question 33Occupational Health

Which of the following is a recognised occupational lung disease caused by inhalation of asbestos fibres?

  1. Farmer's lung
  2. Silicosis
  3. Asbestosis Correct answer.
  4. Byssinosis

Explanation

Asbestosis is a progressive fibrotic lung disease caused by inhalation of asbestos fibres, and asbestos exposure also causes mesothelioma and lung cancer. Byssinosis is associated with cotton dust, farmer's lung with mouldy hay, and silicosis with respirable crystalline silica. Each disease has a distinct causative agent.

Question 34Occupational Health

An SHO finds that maintenance workers are exposed to a solvent vapour above the permissible exposure limit during tank cleaning. Which action should be taken first?

  1. Stop the task and investigate engineering controls to reduce exposure Correct answer.
  2. Record the exposure and review it at the next annual audit
  3. Issue respirators and continue the work without changes
  4. Increase the frequency of medical examinations

Explanation

When exposure exceeds the permissible limit, the priority is to stop or restrict the task and address the source through engineering controls such as local exhaust ventilation or enclosed systems. Relying on respirators alone is a lower-order control and does not correct the underlying problem. Medical examinations do not reduce exposure.

Question 35Occupational Health

An SHO is evaluating a local exhaust ventilation system for a welding bay. Which parameter is most important to verify its effectiveness?

  1. The number of welders employed
  2. The capture velocity at the source of fume generation Correct answer.
  3. The noise level of the fan motor
  4. The colour of the ducting

Explanation

The performance of local exhaust ventilation depends primarily on achieving adequate capture velocity at the point where contaminants are released, so that fume is drawn into the hood before entering the breathing zone. Duct colour, fan noise and staffing levels do not determine capture effectiveness. Regular checks of capture velocity and system condition are essential.

Question 36Occupational Health

An SHO is planning health surveillance for workers exposed to hand-arm vibration. Which approach is most appropriate?

  1. Pre-placement and periodic assessment for vibration white finger symptoms Correct answer.
  2. Annual chest X-ray for all exposed workers
  3. Audiometry every six months
  4. Routine blood lead monitoring

Explanation

Health surveillance for hand-arm vibration focuses on early detection of vascular and neurological symptoms such as tingling, numbness and blanching of the fingers, using structured questionnaires and clinical assessment. Chest X-rays, blood lead and audiometry address different hazards. Early identification allows exposure reduction before the condition becomes disabling.

Question 37Occupational Health

An SHO is assessing a worker who develops asthma-like symptoms after starting work with a new isocyanate-based adhesive. Which step is most appropriate?

  1. Increase the use of a dust mask during application
  2. Remove the worker from further exposure and refer for medical assessment Correct answer.
  3. Advise the worker to continue work and monitor symptoms at home
  4. Wait for the next scheduled health surveillance review

Explanation

Isocyanates are potent respiratory sensitisers, and symptoms suggestive of occupational asthma require prompt removal from exposure and referral for specialist assessment. Continued exposure can lead to irreversible asthma. A dust mask is not adequate protection against isocyanate vapour or aerosol.

Question 38Occupational Health

An SHO is investigating a suspected outbreak of Legionnaires' disease among workers in a building with a cooling tower. Which control measure is most important?

  1. Distributing face masks to all office staff
  2. Increasing the building's heating set point
  3. Restricting access to the building's cafeteria
  4. Implementing a water treatment and maintenance programme for the cooling tower Correct answer.

Explanation

Legionella bacteria multiply in warm water systems such as cooling towers and can be disseminated in aerosols. Effective control depends on regular water treatment, biocide dosing, cleaning and temperature management to prevent colonisation. Face masks and unrelated building changes do not address the source.

Question 39Occupational Health

An SHO is reviewing the results of personal air sampling for a worker exposed to a volatile organic compound. Which statement best interprets the result?

  1. The result can be used to diagnose occupational disease directly
  2. The result is valid only if the worker was wearing a respirator
  3. The result proves that the worker is suffering from poisoning
  4. The result reflects only the exposure during the sampling period and must be compared with the relevant exposure limit Correct answer.

Explanation

Personal air sampling measures the airborne concentration in the worker's breathing zone over the sampling period, and the result is interpreted by comparison with the appropriate occupational exposure limit. It indicates exposure, not absorbed dose or clinical disease. Sampling during respirator use would not reflect workplace exposure.

Question 40Occupational Health

An SHO is designing a health surveillance programme for workers exposed to lead. Which biological monitoring parameter is most appropriate for assessing recent exposure?

  1. Serum creatinine
  2. Blood lead concentration Correct answer.
  3. Haemoglobin A1c
  4. Urinary glucose

Explanation

Blood lead concentration is the standard biological indicator of recent lead exposure and is used in health surveillance to decide on removal from exposure. Serum creatinine, urinary glucose and HbA1c assess kidney function and diabetes, not lead absorption. Biological monitoring complements air monitoring by reflecting absorbed dose.

Question 41Occupational Health

An SHO is advising a laboratory that uses formaldehyde. Which control measure should be given priority?

  1. Scheduling work at the end of the day
  2. Displaying hazard warning signs on the door
  3. Substituting with a less hazardous fixative or using a closed system Correct answer.
  4. Providing surgical masks to all laboratory staff

Explanation

Formaldehyde is a respiratory irritant and carcinogen, so the priority is to eliminate or reduce exposure through substitution or closed handling systems. Warning signs and timing changes are administrative measures that do not reduce the hazard. Surgical masks are not effective against formaldehyde vapour.

Question 42Occupational Health

An SHO is assessing a task that involves lifting heavy boxes repeatedly. Which factor contributes most to the risk of musculoskeletal injury?

  1. The height of the ceiling in the storeroom
  2. The weight of the load and the frequency of lifting Correct answer.
  3. The colour of the boxes being lifted
  4. The number of workers in the department

Explanation

The risk of musculoskeletal injury in manual handling depends on the load weight, lifting frequency, posture, and horizontal and vertical distance of the load from the body. Box colour, staffing numbers and ceiling height do not directly determine the biomechanical load. Risk assessment should focus on these task variables.

Question 43Occupational Health

An SHO is developing a programme to prevent needlestick injuries in a hospital. Which control measure should be prioritised?

  1. Introducing safety-engineered sharps devices and safe disposal systems Correct answer.
  2. Providing hand hygiene training only
  3. Increasing the frequency of staff meetings
  4. Requiring staff to sign an incident declaration form

Explanation

Safety-engineered sharps devices and secure sharps disposal containers are engineering controls that reduce the likelihood of injury at source. Hand hygiene is important for infection control but does not prevent the injury itself. Administrative measures alone are less effective than engineering controls.

Question 44Occupational Health

An SHO is evaluating the effectiveness of a respiratory protection programme. Which element is essential to ensure adequate protection?

  1. Annual fit testing and training for each user Correct answer.
  2. Using respirators only during inspections
  3. Choosing the cheapest respirator available
  4. Allowing workers to share respirators between shifts

Explanation

Fit testing verifies that a respirator seals properly on the individual's face, and training ensures correct donning, use and maintenance. Sharing respirators and using them only during inspections compromise protection. Cost should not override the selection of a suitable, certified respirator.

Question 45Occupational Health

An SHO is investigating an outbreak of contact dermatitis among workers handling epoxy resins. Which measure is most likely to be effective?

  1. Providing barrier creams as the sole control
  2. Substituting with less sensitising materials and improving glove selection Correct answer.
  3. Encouraging workers to wash hands more frequently with solvent
  4. Increasing the frequency of skin examinations

Explanation

Epoxy resins are skin sensitisers, and the most effective control is to substitute with less sensitising products and to select gloves that are chemically resistant to the specific resin. Barrier creams are not a substitute for adequate gloves. Washing with solvent can worsen dermatitis by defatting the skin.

Question 46Occupational Health

An SHO is assessing a worker who reports numbness and blanching of the fingers after using a chainsaw. Which condition is most consistent with this presentation?

  1. Carpal tunnel syndrome
  2. Raynaud's disease unrelated to work
  3. Hand-arm vibration syndrome Correct answer.
  4. Dupuytren's contracture

Explanation

Hand-arm vibration syndrome includes vascular symptoms (vibration white finger) and neurological symptoms such as numbness, and is associated with prolonged use of vibrating tools such as chainsaws. Carpal tunnel syndrome causes median nerve symptoms, and Dupuytren's contracture causes palmar fibrosis. The occupational history is central to attributing the condition to vibration.

Question 47Occupational Health

An SHO is reviewing a chemical health risk assessment for a process using a carcinogenic substance. Which principle should guide the control strategy?

  1. Control measures can be deferred until monitoring shows exceedance
  2. Exposure is acceptable as long as no symptoms are reported
  3. Exposure should be reduced to as low as reasonably practicable, with substitution considered first Correct answer.
  4. The permissible exposure limit is the only target to achieve

Explanation

For carcinogens, there is no known safe threshold, so the aim is to reduce exposure to as low as reasonably practicable, starting with substitution or elimination. Waiting for symptoms or monitoring exceedances is inconsistent with prevention. Compliance with an exposure limit is a minimum, not the endpoint.

Question 48Occupational Health

An SHO is evaluating a worker's exposure to a substance with a skin notation in the exposure limit list. What does this notation indicate?

  1. The substance causes only local skin irritation
  2. The substance is safe to handle without gloves
  3. Air monitoring alone is sufficient to assess exposure
  4. The substance can be absorbed through the skin and contribute to systemic exposure Correct answer.

Explanation

A skin notation indicates that cutaneous absorption may be a significant route of exposure and can contribute to systemic dose even when airborne concentrations are below the limit. Therefore, air monitoring alone may underestimate exposure, and biological monitoring and skin protection are important. The notation does not mean the substance is safe to handle.

Question 49Occupational Health

An SHO is investigating a cluster of pulmonary tuberculosis cases among healthcare workers. Which control measure represents the highest level of the hierarchy of control?

  1. Educating staff on cough etiquette
  2. Using engineering controls such as negative-pressure isolation rooms and ventilation Correct answer.
  3. Providing N95 respirators to staff
  4. Screening patients for symptoms at entry

Explanation

Engineering controls such as negative-pressure rooms and adequate ventilation remove or dilute infectious aerosols at source and are higher in the hierarchy than administrative controls or PPE. Screening and education are administrative measures, and respirators are PPE. A combination is used, but engineering controls provide the most reliable protection.

Question 50Occupational Health

An SHO is assessing the risk of heat stress in a foundry. Which combination of factors should be evaluated?

  1. Air temperature only
  2. Vibration and dust concentration
  3. Air temperature, humidity, radiant heat, air movement and workload Correct answer.
  4. Noise level and lighting

Explanation

Heat stress results from the combined effect of environmental factors (air temperature, humidity, radiant heat and air movement) and personal factors such as metabolic workload and clothing. Assessing temperature alone can underestimate risk. Noise, lighting, vibration and dust are unrelated to thermal load.