NEBOSH National General Certificate Chemical, Biological and Health Hazards Syllabus

Chemical, Biological and Health Hazards syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Chemical, Biological and Health Hazards in NEBOSH National General Certificate, not a summary of it.

1. 1

   Hazardous Substances

   4 topics

   • Forms and Classification of Substances
     • Dusts, fumes, gases, mists, vapours and liquids
     • CLP Regulation hazard pictograms
     • Safety data sheets
   • Routes of Entry and Health Effects
     • Inhalation, absorption, ingestion and injection
     • Acute versus chronic effects
     • Local versus systemic effects
   • Assessment Under COSHH
     • COSHH 2002 requirements
     • Workplace exposure limits
     • Air sampling and health surveillance
   • Controlling Exposure to Substances
     • Elimination, substitution and enclosure
     • Local exhaust ventilation
     • Respiratory protective equipment
2. 2

   Specific Agents and Biological Hazards

   3 topics

   • Common Hazardous Agents
     • Asbestos and silica
     • Lead and solvents
     • Carbon monoxide and isocyanates
   • Biological Agents
     • Bacteria, viruses and fungi
     • Legionella and leptospirosis
     • Bloodborne pathogens
   • Safe Storage and Disposal of Substances
     • Storage compatibility and containment
     • Waste classification and disposal duties
3. 3

   Occupational Health and Wellbeing

   4 topics

   • Work-Related Ill Health
     • Distinguishing health from safety
     • Skin disorders and dermatitis
     • Occupational cancers and asthma
   • Work-Related Stress
     • Causes and symptoms of stress
     • HSE Management Standards
     • Controlling stress at work
   • Violence, Alcohol and Drugs at Work
     • Managing work-related violence
     • Effects of alcohol and drugs on safety
     • Drug and alcohol policies
   • Promoting Health and Wellbeing
     • Health surveillance programmes
     • Wellbeing initiatives and support

Chemical, Biological and Health Hazards flashcards for NEBOSH National General Certificate

24 of 50 cards from the Chemical, Biological and Health Hazards deck — real questions with worked answers.

1. Under the Globally Harmonised System (GHS)/CLP, what are the three main classification categories of hazardous substances?

   Physical hazards (e.g. flammable, explosive, oxidising), health hazards (e.g. toxic, corrosive, carcinogenic), and environmental hazards (e.g. aquatic toxicity).

2. List the physical forms in which hazardous substances can exist in the workplace.

   Dusts, fumes, gases, mists, vapours, liquids, solids, fibres, and aerosols (smoke). Each form affects how the substance can enter the body and how it is controlled.

3. What is the difference between a dust and a fume?

   A dust is solid particles dispersed in air by mechanical action (grinding, crushing). A fume is fine solid particles formed when a vaporised metal/solid condenses in air (e.g. welding fume), with much smaller particle size.

4. Distinguish between a vapour, a gas and a mist.

   A vapour is the gaseous form of a substance that is normally liquid/solid at room temperature (e.g. solvent vapour). A gas is a substance in gaseous state at room temperature and pressure. A mist is fine liquid droplets suspended in air (e.g. from spraying).

5. What are the four main routes of entry of hazardous substances into the body?

   Inhalation (breathing in), absorption through the skin (and eyes), ingestion (swallowing), and injection (penetration through skin, e.g. needlestick or high-pressure injection). Inhalation is the most common in occupational settings.

6. Define an 'acute' health effect and give an example.

   An acute effect is a rapid-onset, usually short-term effect from a single or short exposure, often reversible, e.g. dizziness or unconsciousness from solvent vapour, or a chemical burn from acid.

7. Define a 'chronic' health effect and give an example.

   A chronic effect develops slowly over a long period, usually from repeated/prolonged low-level exposure, often irreversible, e.g. silicosis from silica dust or occupational cancer from asbestos.

8. What is the difference between a local effect and a systemic effect?

   A local effect occurs at the point of contact (e.g. dermatitis on skin, lung irritation). A systemic effect occurs in the body away from the point of entry after the substance is absorbed and transported (e.g. lead damaging the nervous system).

9. Name the body's main defence mechanisms of the respiratory system against airborne contaminants.

   Nasal hairs and mucus trap large particles; the ciliary escalator (cilia + mucus) moves trapped particles up to be coughed/swallowed; macrophages engulf particles reaching the alveoli; sneezing and coughing expel material.

10. What does COSHH stand for and what is its purpose?

    Control of Substances Hazardous to Health Regulations 2002. It requires employers to assess, prevent or adequately control employees' exposure to substances hazardous to health.

11. What does COSHH NOT cover (excluded substances)?

    Asbestos, lead, and radioactive substances (covered by their own regulations), and substances hazardous only because they are flammable, explosive or at high/low temperature/pressure (physical hazards).

12. What does a COSHH risk assessment require? List the key steps.

    Identify hazardous substances and who could be harmed; evaluate the risks; decide on control measures (following the hierarchy); record significant findings; provide information/training/health surveillance; and review regularly or when circumstances change.

13. What is a Safety Data Sheet (SDS) and how many sections does it contain?

    A document provided by the supplier giving information on a substance's hazards and safe handling. The standardised SDS has 16 sections (e.g. identification, hazards, first aid, handling/storage, exposure controls/PPE, toxicological info).

14. What is a Workplace Exposure Limit (WEL)?

    The maximum concentration of an airborne hazardous substance, averaged over a reference period, to which workers may be exposed by inhalation. WELs are listed in HSE document EH40.

15. What are the two reference periods used for Workplace Exposure Limits (WELs)?

    Long-term exposure limit (LTEL) averaged over an 8-hour Time-Weighted Average (TWA) for chronic effects; and short-term exposure limit (STEL) averaged over 15 minutes for acute effects.

16. State the formula for an 8-hour Time-Weighted Average (TWA) exposure for a single continuous exposure.

    $$\text{TWA}_{8h} = \frac{C \times T}{8}$$ where $C$ is the measured concentration and $T$ is the exposure duration in hours, normalised to an 8-hour reference period.

17. Write the general formula for a Time-Weighted Average over several different exposure periods in an 8-hour shift.

    $$\text{TWA} = \frac{C_1 T_1 + C_2 T_2 + \cdots + C_n T_n}{8}$$ where each $C_i$ is the concentration during period $T_i$ (hours) and the total is divided by the 8-hour reference period.

18. A worker is exposed to a solvent at $300\ \mathrm{mg/m^3}$ for 6 hours and zero for the rest of an 8-hour shift. Calculate the 8-hour TWA.

    $$\text{TWA} = \frac{(300 \times 6) + (0 \times 2)}{8} = \frac{1800}{8} = 225\ \mathrm{mg/m^3}$$

19. In what units are Workplace Exposure Limits expressed?

    Parts per million ($\mathrm{ppm}$) by volume for gases and vapours, and milligrams per cubic metre ($\mathrm{mg/m^3}$) for the mass of substance per volume of air (used for dusts, fumes and as an alternative for gases/vapours).

20. What does the skin notation 'Sk' against a substance in EH40 indicate?

    That the substance can be absorbed significantly through the skin, so the WEL alone does not protect against the total body uptake; skin absorption must also be controlled.

21. State the hierarchy of control for exposure to hazardous substances under COSHH (general principles).

    Eliminate/substitute the substance; control at source (enclosure, LEV, process change); reduce numbers exposed and exposure time (organisational); provide PPE/RPE as a last resort. Always control at source before relying on PPE.

22. What is Local Exhaust Ventilation (LEV) and name its five basic components.

    An engineering control that captures contaminant at or near its source. Components: hood/intake, ducting, air cleaner/filter, fan (air mover), and discharge/exhaust to a safe place.

23. How often must an LEV system be thoroughly examined and tested under COSHH?

    At least once every 14 months for most systems (more frequently for certain high-risk processes such as some blasting and grinding operations).

24. What is the difference between dilution ventilation and local exhaust ventilation?

    Dilution (general) ventilation reduces contaminant concentration by mixing with large volumes of fresh air; suitable for low-toxicity, low-quantity contaminants. LEV captures contaminant at source before it spreads, suitable for more toxic substances.

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