Occupational Health, Industrial Hygiene and Ergonomics

Introduction

Production systems depend on people, equipment, materials and information. Industrial safety traditionally focuses on preventing immediate injuries such as falls, burns and struck-by incidents. Occupational health and industrial hygiene address a different but equally important question: how can work exposures cause illness over days, years or decades, and how can those exposures be controlled before disease develops?

Workers may be exposed to excessive noise, mechanical vibration, heat, dust, fumes, radiation, chemicals, biological agents and ergonomic stressors. These hazards can interact. For example, heat may increase chemical absorption, noise may mask warning signals, and fatigue may increase the likelihood of manual-handling injuries. Effective production management therefore treats health protection as an operational responsibility rather than as an isolated medical activity.

Industrial hygiene is the science and practice of anticipating, recognising, evaluating and controlling workplace hazards. Occupational health complements it through health-risk assessment, medical surveillance, health promotion and the investigation of work-related disease. Ergonomics applies knowledge of human capabilities and limitations to the design of jobs, tools, workplaces and organisations.

Regulatory exposure limits differ between jurisdictions. Managers must therefore consult the applicable national legislation, approved codes of practice and authoritative occupational-exposure-limit tables. The numerical values in this chapter illustrate methods and decision-making; they do not replace legal requirements.

Learning objectives

By the end of this chapter, the learner should be able to:

1. distinguish occupational health, industrial hygiene and ergonomics;
2. identify routes of exposure and explain dose–response relationships;
3. assess noise, vibration, heat, dust, fumes, radiation and hazardous substances;
4. select appropriate monitoring methods and interpret exposure limits;
5. apply the hierarchy of controls, including ventilation and substitution;
6. explain health surveillance and the prevention of occupational disease;
7. analyse manual-handling and workstation risks;
8. recommend practical controls for production environments; and
9. evaluate the managerial, ethical and legal implications of occupational-health decisions.

1. Foundations of occupational health and industrial hygiene

1.1 Important terminology

Hazard is a source or situation with the potential to cause harm. Risk is the combination of the likelihood of harm and its severity. Exposure occurs when a worker comes into contact with a hazard. Dose is the amount absorbed or received by the body. A hazard does not necessarily produce disease unless exposure is sufficient in intensity, duration or frequency, and individual susceptibility also matters.

Exposure may occur through inhalation, skin absorption, ingestion, injection or, in the case of physical agents, energy transfer to the body. In manufacturing, inhalation is often dominant, but dermal exposure can be critical for solvents, pesticides, sensitising agents and corrosive substances.

A useful conceptual model is:

This is a conceptual relationship, not a universal numerical equation. It reminds the assessor that eliminating a hazard, reducing exposure or protecting susceptible workers can reduce risk.

1.2 The industrial-hygiene cycle

A competent hygiene programme follows a repeating cycle:

1. Anticipation: predict hazards during process design, procurement and change management.
2. Recognition: identify agents, tasks, routes, exposed groups and vulnerable conditions.
3. Evaluation: measure or estimate exposure and compare it with valid criteria.
4. Control: apply the hierarchy of controls.
5. Verification: confirm that controls work through re-monitoring, inspection and health data.

The process should be based on similar exposure groups (SEGs): workers who perform comparable tasks under comparable conditions and are expected to have similar exposures. Sampling every worker is rarely necessary, but the selection of SEGs must be justified and reviewed when processes, materials or work practices change.

1.3 Exposure limits and dose concepts

Common limit concepts include:

• Time-weighted average (TWA): average exposure over a specified reference period, commonly an eight-hour shift.
• Short-term exposure limit (STEL): an average exposure over a short period, often 15 minutes.
• Ceiling limit: a concentration that should not be exceeded at any time.
• Peak limit: a maximum level defined by a particular standard.
• Action level: a concentration or dose at which additional controls, monitoring or medical programmes are triggered.

Limits are usually intended to protect most healthy workers under specified conditions; they are not guarantees of zero risk. Some substances, including carcinogens, reproductive toxicants and sensitizers, may require control to the lowest reasonably practicable level rather than reliance on a single limit.

For a contaminant with changing concentration, an eight-hour TWA can be calculated as:

Here, Cᵢ is the measured concentration during period i and tᵢ is the duration of that period. Concentration and time units must be consistent. This calculation is appropriate when concentration is reasonably represented by discrete time periods and the applicable standard uses a linear time average. It does not by itself evaluate short-term peaks or ceiling requirements.

Worked example. A worker experiences 20 ppm for 2 hours, 5 ppm for 3 hours and 0 ppm for 3 hours. The eight-hour TWA is:

The result must be compared with the applicable limit and any STEL or ceiling requirement. A low TWA cannot justify ignoring a brief hazardous peak.

2. Exposure assessment and monitoring strategy

2.1 From hazard inventory to sampling plan

A monitoring plan should identify the agent, source, task, route, affected SEG, expected variability, sampling method, analytical laboratory and decision rule. Personal sampling generally provides the best estimate of worker exposure because the instrument travels in the breathing zone. Area sampling is valuable for source identification, engineering-control verification and background mapping, but it may not represent personal exposure.

Sampling should include representative high-exposure tasks, different shifts, normal and abnormal operations, cleaning, maintenance, start-up, shutdown and foreseeable failures. A single sample is rarely sufficient to characterise a variable process. Results should be documented with production rate, material used, ventilation status, weather where relevant, work practice and instrument details.

Direct-reading instruments provide immediate information and can reveal peaks, leaks and control failures. Laboratory methods may provide better selectivity and sensitivity but usually give delayed results. Instruments require calibration, appropriate detection limits, trained users and quality assurance. A “non-detect” result means the concentration was below the method’s detection capability, not necessarily zero.

2.2 Interpretation and uncertainty

Exposure assessment contains uncertainty from sampling duration, instrument accuracy, laboratory analysis, worker selection and day-to-day variability. Managers should avoid treating a limit as a sharp boundary between safe and unsafe. Results near a limit require competent interpretation, additional sampling and conservative control decisions.

Exposure data should be trended. A rising average, increasing number of excursions or repeated maintenance failures may indicate deteriorating control even when individual measurements remain below a limit. Results should be communicated in understandable language, with access for workers and their representatives.

3. Physical agents

3.1 Noise

Noise can cause permanent hearing loss, tinnitus, interference with communication, fatigue and failure to hear alarms. Risk depends on sound level, duration, frequency distribution, impulsiveness and individual susceptibility.

Sound pressure level is expressed in decibels (dB), a logarithmic unit. For sound pressure level:

where p is the measured root-mean-square sound pressure and p₀ is the reference sound pressure, conventionally 20 μPa in air. Because the scale is logarithmic, a 3 dB increase approximately doubles acoustic energy, although perceived loudness does not follow a simple linear relationship.

Personal noise dosimeters estimate a worker’s daily noise dose. A simplified dose model used by some regulatory systems is:

where Cᵢ is the actual time spent at sound level i and Tᵢ is the permitted time at that level under the selected standard. This formula is valid only when the same exchange rate, criterion level and regulatory method are used consistently. Different standards use different criterion levels and exchange rates; therefore, dose values must not be compared without checking the method.

Controls should begin with quieter equipment, low-noise purchasing specifications, enclosure, isolation, damping, preventive maintenance and increased distance. Administrative controls and hearing protection are supplementary, not substitutes for feasible engineering controls. Audiometric surveillance can detect standard-threshold shifts, but it cannot compensate for uncontrolled noise.

3.2 Mechanical vibration

Hand–arm vibration from grinders, impact tools and chainsaws can cause vascular, neurological and musculoskeletal disorders. Whole-body vibration from vehicles, mobile plant and poorly isolated platforms can contribute to back pain, fatigue and impaired control.

Vibration is commonly assessed using frequency-weighted root-mean-square acceleration. For orthogonal axes, a combined value may be calculated as:

where aₓ, aᵧ and a_z are weighted acceleration values in three perpendicular axes. This expression is appropriate when the assessment standard permits vector summation and the components are measured on comparable bases. Exposure duration and the relevant frequency weighting must also be considered; acceleration alone is not a complete risk assessment.

Controls include selecting low-vibration tools, maintaining rotating components, balancing wheels, isolating seats and platforms, reducing trigger time, rotating tasks carefully and preventing cold conditions that worsen vascular symptoms. Job rotation should not be used to disguise excessive individual or group exposure.

3.3 Heat and thermal stress

Heat stress depends on air temperature, humidity, radiant heat, air movement, clothing, workload, acclimatisation, hydration and individual health. The same air temperature can produce very different risks in a furnace area and an air-conditioned office.

Assessment commonly uses a wet-bulb globe temperature (WBGT) approach, with corrections and work–rest guidance specified by the applicable standard. WBGT is a screening index rather than a direct measure of core temperature. A robust heat programme includes engineering cooling, shielding from radiant sources, ventilation, cool rest areas, potable water, acclimatisation, work scheduling, training and emergency response for heat illness.

Workers with confusion, collapse, seizures or very high body temperature may have heat stroke, a medical emergency. First aid should follow trained emergency procedures, including rapid cooling and urgent medical assistance. Fitness-for-work decisions must respect privacy and should not stigmatise workers with medical conditions.

3.4 Ionising and non-ionising radiation

Ionising radiation includes X-rays, gamma rays and particles capable of producing ionisation and cellular damage. Controls follow time reduction, distance increase and shielding, supported by source security, controlled areas, dosimetry, interlocks and competent radiation-protection supervision. Exposure records and medical arrangements must comply with national law.

Non-ionising radiation includes ultraviolet, infrared, radiofrequency, microwave and laser radiation. Hazards include skin and eye injury, burns and, for lasers, retinal damage. Controls include enclosed beams, interlocked guards, appropriate wavelength-specific eye protection, warning systems and authorised access.

Radiation protection requires careful source inventory, calibrated instruments and conservative control of unusual events. Workers must understand that absence of immediate sensation does not prove absence of exposure.

4. Dusts, fumes and hazardous substances

4.1 Aerosols and airborne contaminants

Dust consists of solid particles generated by mechanical action. Fume commonly refers to very fine particles formed when a vapor condenses after heating, as in welding. Mist consists of liquid droplets. Vapour is the gaseous form of a substance that is normally liquid or solid at room temperature. Particle size affects where material deposits in the respiratory system, but toxicity, shape, solubility and surface chemistry are also important.

Health effects include irritation, asthma, sensitisation, chronic obstructive disease, pneumoconiosis, metal poisoning and cancer. Hazard communication must include labels, safety data sheets, inventories, process information and worker training. Safety data sheets are important sources of information but should be supplemented by competent assessment of the actual task.

4.2 The hierarchy of controls

Controls should be selected in this order:

1. Elimination: remove the hazardous task or material.
2. Substitution: replace it with a less hazardous alternative.
3. Engineering controls: enclose, isolate or capture the hazard.
4. Administrative controls: change scheduling, procedures, training or access.
5. Personal protective equipment (PPE): protect the worker when residual risk remains.

PPE is essential for many tasks, but it depends on correct selection, fit, compatibility, maintenance and user behaviour. Respirators require a written programme, medical evaluation where required, fit testing, cartridge management and facial-hair controls where relevant.

4.3 Local exhaust ventilation

Local exhaust ventilation (LEV) captures contaminants near their source before they enter the worker’s breathing zone. A basic LEV system consists of a hood, ducting, air cleaner, fan and discharge arrangement. Capture performance depends on hood design, distance, airflow, cross-drafts, enclosure and maintenance.

For an idealised hood or opening, volumetric airflow is:

where Q is airflow in m³/s, A is opening or duct area in m² and V is average air velocity in m/s. The equation is dimensionally consistent, but it does not determine the capture velocity required for a particular contaminant. That requirement depends on the hazard, release characteristics and hood design. LEV systems require commissioning, periodic examination, airflow checks and prompt repair of alarms or failed fans.

General dilution ventilation may control low-toxicity, uniformly distributed contaminants, but it is usually inferior to source capture for highly toxic, carcinogenic or variable releases. Ventilation must not create cross-contamination or discharge pollutants into neighbouring work areas.

4.4 Chemical risk management

A chemical assessment should consider intrinsic hazard, quantity, concentration, volatility, reactivity, route of exposure, task duration, storage, incompatible materials and emergency scenarios. Good practice includes closed transfer, automation, leak detection, secondary containment, segregation, housekeeping, spill procedures and waste control.

Special attention is required for sensitizers, carcinogens, reproductive toxicants, corrosives, compressed gases and chemicals that decompose into toxic products. A chemical’s trade name is not enough; the actual composition and impurities must be known. Procurement decisions should include lifecycle hazards, not only purchase price.

5. Health surveillance and occupational disease prevention

Health surveillance is the systematic collection and review of health information to identify work-related effects early and evaluate control effectiveness. It is appropriate when a valid health effect is associated with an identifiable exposure, a suitable detection method exists, and preventive action can be taken.

Examples include audiometry for significant noise exposure, biological monitoring for selected substances, lung-function testing for certain respiratory hazards, skin checks for dermatitis risks and symptom questionnaires for vibration-related disorders. Surveillance must be designed by occupational-health professionals and must not be used as a substitute for exposure control.

A sound programme includes baseline assessment where justified, periodic testing, defined referral criteria, confidential records, worker feedback, trend analysis and prompt investigation of abnormal findings. Employers generally need fitness or control-related information, not unnecessary diagnoses. Medical confidentiality, informed consent, data security and non-discrimination are ethical requirements.

Occupational disease prevention requires primary prevention: eliminate or control the cause before disease occurs. Secondary prevention identifies early effects, while tertiary prevention manages established illness and supports rehabilitation. Reporting and investigation should examine work organisation, process design and exposure history rather than blame the affected worker.

6. Ergonomics and human-centred production

Ergonomics is the scientific discipline concerned with interactions among humans and other elements of a system. Its objective is to optimise human well-being and overall system performance. Ergonomic hazards include force, repetition, awkward posture, contact stress, vibration, insufficient recovery, poor workstation layout, visual demand, cognitive overload and low control over work.

6.1 Manual handling

Manual-handling risk depends on load mass, horizontal reach, vertical location, asymmetry, frequency, duration, coupling quality and environmental conditions. A lifting assessment should observe the actual task, including start and finish positions, carrying distance, team handling, pushing and pulling, unexpected loads and restricted space.

Controls include eliminating manual movement, using conveyors or hoists, reducing load size, improving handles and packaging, bringing work to waist height, reducing reach, arranging materials within the normal work envelope and redesigning production flow. Training in lifting technique is useful but is a lower-level control when the job itself imposes excessive demand.

A common screening model, such as the Revised NIOSH Lifting Equation, estimates a recommended weight limit:

Here, LC is the load constant and HM, VM, DM, AM, FM and CM are horizontal, vertical, distance, asymmetry, frequency and coupling multipliers. The equation applies only within its stated assumptions, such as a two-handed lifting task under defined posture, frequency and load conditions. It should not be applied blindly to one-handed lifting, unstable loads, pushing, pulling, high-speed work or constrained environments. The associated lifting index is:

An LI above 1 indicates that the task exceeds the model’s recommended weight for the assessed conditions; it is a screening signal, not a diagnosis or a guarantee of injury.

6.2 Workstation and tool design

A workstation should allow neutral joint positions, adjustable working height, adequate clearance, appropriate viewing distance, low-force controls, suitable lighting and easy access to frequently used items. Standing work requires opportunities for posture variation and anti-fatigue measures where justified. Seated work requires back support, adjustability and adequate legroom.

Controls should be arranged according to frequency, importance and consequence of error. Displays must be readable under actual lighting, and alarms must be distinguishable from normal process sounds. Tool handles should match hand size, reduce vibration transmission and avoid sharp contact pressure.

Ergonomic design is not merely “fitting the worker to the job.” It adapts the system to a diverse workforce, including differences in stature, strength, age, language, disability and experience. Worker participation is essential because employees often understand variability and workarounds that are invisible to an external observer.

6.3 Organisational and cognitive ergonomics

Shift length, pace, staffing, incentive systems, breaks, autonomy and maintenance reliability influence fatigue and error. A production target that rewards output while ignoring recovery time may transfer cost into injuries, defects, absenteeism and turnover. Fatigue risk management should address scheduling, commuting, overtime, night work, alertness-critical tasks and reporting without retaliation.

7. Integrated control and management application

Occupational-health management should be incorporated into the production-management system. Key mechanisms include design reviews, management of change, contractor controls, preventive maintenance, purchasing specifications, permit-to-work systems, competency assurance, emergency planning and internal audits.

A practical control-selection sequence is:

1. define the health outcome to be prevented;
2. identify the agent, source, pathway and exposed population;
3. determine whether elimination or substitution is feasible;
4. design engineering controls at the source;
5. verify control performance with monitoring;
6. establish procedures and supervision for residual risk;
7. select PPE as the final protective layer; and
8. review exposure, health and production indicators over time.

Useful indicators include percentage of SEGs characterised, overdue exposure assessments, LEV examination results, noise-dose trends, health-surveillance participation, ergonomic improvement closure, chemical incidents and repeated symptoms. Leading indicators should be combined with lagging indicators such as occupational disease, absence and compensation claims.

Technology and AI

Digital sensors, connected dosimeters, wearable heat monitors, vibration loggers and automated ventilation alarms can improve real-time awareness. Data analytics can identify patterns by task, shift or machine. AI may assist with anomaly detection, exposure prediction and ergonomic video analysis, but it must be validated against competent measurements.

Technology creates governance risks. Continuous worker monitoring may intrude on privacy, misclassify activities or be used for disciplinary surveillance. Organisations should define purpose, data minimisation, access rights, retention periods, cybersecurity and human review. An algorithm should support—not replace—professional judgement, worker consultation and legal compliance.

8. Illustrative case study: solvent cleaning in a metal-products plant

Background

An illustrative metal-products plant uses a volatile solvent to clean components before coating. Operators fill open trays, wipe parts manually and place waste cloths in uncovered bins. Several workers report headaches and skin dryness. Production has increased through overtime, while the general ventilation system has remained unchanged.

Problem

Management initially proposes respirators and shorter breaks. This response is incomplete because it does not establish actual exposure, address skin contact or control vapour at the source.

Analysis

A hygiene team forms an SEG consisting of cleaning operators and observes normal production, overtime, replenishment, waste handling and maintenance. Personal vapour sampling is performed using a validated method, with separate short-term samples during tray filling. Area samples map vapour movement toward adjacent workstations. The assessment also reviews the safety data sheet, solvent composition, flammability, ignition sources, glove compatibility and waste storage.

The team finds that average exposure is below the applicable eight-hour limit on ordinary days but approaches the limit during overtime. Short-term peaks occur during tray filling and when waste bins are emptied. Gloves selected for general chemical work show breakthrough in compatibility data. The ventilation system provides dilution but no source capture.

Approach and solution

The plant first trials an aqueous or less hazardous cleaning agent and confirms product-quality requirements. Where solvent remains necessary, it installs closed dispensing, lidded cleaning tanks, self-closing waste containers and LEV at the filling and waste points. Trays are reduced in size, transfer quantities are controlled and replenishment is scheduled during low occupancy. Compatible gloves, splash protection and eye protection are selected using supplier data. Respirators are retained for defined non-routine tasks while engineering controls are commissioned.

Workers receive training on skin protection, spill response, waste closure and symptoms requiring medical advice. A health-surveillance programme is established where justified by the solvent and applicable law. Personal sampling is repeated under high-production conditions, and LEV airflow is checked after maintenance.

Outcome

Follow-up monitoring shows lower average exposure and substantially reduced filling-task peaks. Reports of odour and skin irritation decline. The plant also records fewer rejected components because cleaning concentration and transfer procedures are standardised. The result demonstrates that occupational-health controls can improve both worker protection and process stability.

Learning points

The case illustrates five principles: exposure must be measured under representative conditions; short-term peaks matter; substitution should precede PPE; ventilation requires source capture and verification; and worker health, quality and productivity can improve together when process design is addressed.

Challenges, limitations and governance

Occupational-health decisions are difficult when exposures vary, standards differ, mixtures interact or evidence is incomplete. Economic pressure may encourage postponement of engineering improvements, while workers may fear reporting symptoms. Ethical management requires precaution, transparency and meaningful consultation.

Risk assessments can fail through under-sampling, reliance on area monitors, ignoring maintenance work, assuming PPE is always worn, using outdated limits or treating a normal shift as representative. Ergonomic assessments may also overlook psychosocial conditions and diverse worker capabilities. Competence, independent review and periodic reassessment are therefore necessary.

The organisation should comply with applicable occupational-health, chemical, radiation, environmental, disability, privacy and employment legislation. Contractors and temporary workers deserve equivalent protection. Records should be retained for the periods required by law, particularly where disease latency is long. Procurement, engineering and production managers share responsibility; safety personnel cannot control hazards that the wider organisation continues to create.

Best-practice checklist

• Maintain an up-to-date process and chemical inventory.
• Define SEGs and reassess them after process change.
• Use competent, calibrated sampling and accredited analysis where appropriate.
• Evaluate personal exposure, peaks and unusual tasks.
• Apply elimination, substitution and engineering controls before PPE.
• Commission and maintain LEV; verify its performance.
• Provide effective heat, noise, vibration and radiation programmes.
• Integrate health surveillance with exposure prevention and confidentiality.
• Involve workers in ergonomic design and control selection.
• Treat fatigue, workload and production incentives as health issues.
• Trend data and investigate repeated symptoms or near misses.
• Review controls after maintenance, changes, incidents and new evidence.

Chapter Summary

Occupational health protects workers from disease and impaired function arising from work. Industrial hygiene anticipates, recognises, evaluates and controls chemical, physical and biological exposures. Exposure assessment requires representative sampling, suitable instruments, competent interpretation and awareness of uncertainty. TWA calculations do not replace STEL, ceiling or peak assessment.

Noise, vibration, heat and radiation require agent-specific measurement and controls. Dusts, fumes, vapours and hazardous substances should be managed through the hierarchy of controls, with source capture and substitution preferred to dependence on PPE. Health surveillance supports early detection and control verification but must remain confidential and must never substitute for prevention.

Ergonomics addresses physical, cognitive and organisational design. Manual-handling tools, workstation assessment, worker participation and system-level changes are more reliable than training alone. Effective programmes connect occupational health with production planning, maintenance, procurement, management of change and ethical governance. Technology can improve monitoring, but professional judgement, privacy and worker involvement remain essential.

Key Terms

Action level: A threshold that triggers additional monitoring or preventive action.

Ceiling limit: A concentration that should not be exceeded at any time under a specified standard.

Dose: The amount of a hazard absorbed or received by the body.

Ergonomics: The design of systems to fit human capabilities and limitations.

Exposure: Contact between a worker and a hazard.

Health surveillance: Planned collection and review of health information related to workplace exposure.

Hierarchy of controls: Ordered approach prioritising elimination and substitution over administrative controls and PPE.

Industrial hygiene: Anticipation, recognition, evaluation and control of workplace health hazards.

Local exhaust ventilation: Source-capture ventilation that removes contaminants before they enter the breathing zone.

Noise dose: A cumulative measure of exposure to occupational noise under a specified standard.

Occupational health: Promotion and protection of workers’ physical, mental and social well-being.

Personal sampling: Measurement made on or near the worker to estimate personal exposure.

Similar exposure group: Workers expected to have comparable exposure profiles.

Short-term exposure limit: An exposure average permitted over a defined short period.

Time-weighted average: Exposure averaged over a specified reference period.

Vapour: The gaseous phase of a substance normally liquid or solid at room temperature.

WBGT: A heat-stress screening index incorporating environmental thermal conditions.

Work-related disease: Disease caused or materially contributed to by workplace conditions.

Review Questions

Short Answer Questions

1. Define industrial hygiene and state its five main activities.
2. Distinguish a TWA, STEL and ceiling limit.
3. Why is personal sampling generally more representative than area sampling?
4. State three engineering controls for occupational noise.
5. Explain why PPE is considered the final level in the hierarchy of controls.

Long Answer Questions

1. Explain how a production manager should establish and maintain an industrial-hygiene monitoring programme.
2. Discuss the health effects, assessment methods and controls associated with occupational noise and vibration.
3. Describe the design and verification principles of local exhaust ventilation.
4. Explain how health surveillance contributes to the prevention of occupational disease while protecting confidentiality.
5. Discuss how ergonomics can improve manual handling, workstation design and production performance.

Analytical / Application Questions

1. A worker is exposed to 12 ppm of a contaminant for 2 hours, 4 ppm for 4 hours and 0 ppm for 2 hours. Calculate the eight-hour TWA and explain why short-term monitoring may still be required.
2. A factory reports repeated heat complaints despite installing fans. Analyse the likely limitations of the existing approach and propose an integrated heat-stress programme.
3. A plant relies on job rotation and back belts to control a high-frequency lifting task. Evaluate this strategy using the hierarchy of controls and recommend a redesigned solution.

Multiple Choice Questions with Answers

Question 1

Which activity is the first step in the industrial-hygiene cycle?

A. Anticipation

B. Personal protective equipment selection

C. Medical diagnosis

D. Incident punishment

Correct Answer: A. Anticipation

Question 2

A worker experiences 10 ppm for 2 hours and 2 ppm for 6 hours. What is the eight-hour TWA?

A. 2 ppm

B. 4 ppm

C. 6 ppm

D. 12 ppm

Correct Answer: B. 4 ppm

Question 3

Which control most directly captures solvent vapour at the point where it is released?

A. General training

B. Hearing protection

C. Local exhaust ventilation

D. Job title redesign

Correct Answer: C. Local exhaust ventilation

Question 4

Which statement about a ceiling limit is correct?

A. It is an average over an entire career

B. It should not be exceeded at any time under the applicable standard

C. It applies only to noise

D. It is always lower than every action level

Correct Answer: B. It should not be exceeded at any time under the applicable standard

Question 5

Which hazard is most associated with hand–arm vibration syndrome?

A. Vascular and neurological effects in the hands and arms

B. Ionising radiation burns

C. Chemical eye burns only

D. Hearing-threshold shift only

Correct Answer: A. Vascular and neurological effects in the hands and arms

Question 6

What is the preferred first response in the hierarchy of controls when a hazardous solvent can be removed from a process?

A. Provide thicker gloves

B. Increase worker rotation

C. Eliminate the solvent use

D. Issue a warning poster

Correct Answer: C. Eliminate the solvent use

Question 7

Which statement best describes health surveillance?

A. It replaces engineering controls

B. It systematically reviews health information related to workplace exposure

C. It is used only after a fatal accident

D. It publicly identifies workers with illness

Correct Answer: B. It systematically reviews health information related to workplace exposure

Question 8

Which factor is relevant to manual-handling risk?

A. Load reach and frequency

B. Company logo colour

C. Payroll frequency only

D. Building age alone

Correct Answer: A. Load reach and frequency

Question 9

For the equation Q = A × V, what does Q represent?

A. Airflow volume per unit time

B. Chemical concentration

C. Sound pressure level

D. Radiation dose

Correct Answer: A. Airflow volume per unit time

Question 10

Why should AI-based ergonomic video analysis be independently validated?

A. Algorithms always eliminate privacy concerns

B. It may misclassify tasks and cannot replace competent judgement

C. It makes worker consultation unnecessary

D. It guarantees compliance with every exposure limit

Correct Answer: B. It may misclassify tasks and cannot replace competent judgement