NEBOSH Chemical and Biological Hazards 3 — Questions and Answers
Question 1: What is the purpose of a COSHH assessment under Regulation 6?
- To determine the cost of chemicals used
- To identify hazardous substances present, assess the risks to health from exposure, and determine the control measures needed (Correct answer)
- To count the number of chemical containers in storage
- To create a list of approved chemical suppliers
Correct answer: To identify hazardous substances present, assess the risks to health from exposure, and determine the control measures needed
A COSHH assessment under Regulation 6 requires the employer to make a suitable and sufficient assessment of the risks to employee health from exposure to hazardous substances. This involves identifying what substances are present, who may be exposed and how, the likely level of exposure, and what control measures are needed to prevent or adequately control exposure.
Question 2: Inhalation is considered the most significant route of entry for occupational exposure to hazardous substances. Why?
- Because the lungs have no natural defence mechanisms
- Because the lungs have a very large surface area with a thin membrane and rich blood supply, allowing rapid absorption of inhaled substances into the bloodstream (Correct answer)
- Because people breathe faster at work than at home
- Because most hazardous substances are gases
Correct answer: Because the lungs have a very large surface area with a thin membrane and rich blood supply, allowing rapid absorption of inhaled substances into the bloodstream
The lungs present approximately 70 square metres of surface area with an extremely thin membrane (0.2-0.6 micrometres) and an extensive blood supply. Inhaled substances (dusts, fumes, vapours, gases, mists) can rapidly pass through this membrane into the bloodstream, reaching target organs within seconds. The large volume of air breathed (10,000 litres per 8-hour shift) means significant quantities can be inhaled.
Question 3: Under GHS labelling, what information must appear on a chemical product label?
- Only the product name
- Product identifier, supplier details, GHS pictograms, signal word, hazard statements, and precautionary statements (Correct answer)
- Only the hazard pictogram
- The chemical formula and molecular weight only
Correct answer: Product identifier, supplier details, GHS pictograms, signal word, hazard statements, and precautionary statements
A GHS-compliant label must include: product identifier (chemical name or product name), supplier identification (name, address, telephone), relevant GHS hazard pictograms, signal word (Danger or Warning), hazard statements (H-statements describing the nature and degree of hazard), and precautionary statements (P-statements covering prevention, response, storage, and disposal).
Question 4: What is the difference between a Group 2 and a Group 3 biological agent?
- Group 2 is found in animals only, Group 3 in humans only
- Group 2 can cause human disease but effective treatment is usually available and community spread is unlikely; Group 3 can cause severe disease, may spread to the community, but effective treatment or prophylaxis usually exists (Correct answer)
- Group 2 requires BSL-4 containment, Group 3 requires BSL-2
- There is no practical difference between the two groups
Correct answer: Group 2 can cause human disease but effective treatment is usually available and community spread is unlikely; Group 3 can cause severe disease, may spread to the community, but effective treatment or prophylaxis usually exists
Group 2 agents can cause human disease and may be a hazard to workers, but are unlikely to spread to the community, and effective prophylaxis or treatment is usually available (e.g., Clostridium tetani). Group 3 agents can cause severe human disease, may present a serious hazard, and may spread to the community, but effective prophylaxis or treatment usually exists (e.g., Mycobacterium tuberculosis, HIV).
Question 5: What control measures should be implemented to prevent Legionella in workplace water systems?
- Adding chlorine to drinking water coolers only
- Keeping hot water above 60°C at the calorifier and above 50°C at outlets, cold water below 20°C, flushing infrequently used outlets, cleaning and disinfecting systems, and carrying out regular monitoring (Correct answer)
- Replacing all water pipes with copper every year
- Only testing water once when the building is first occupied
Correct answer: Keeping hot water above 60°C at the calorifier and above 50°C at outlets, cold water below 20°C, flushing infrequently used outlets, cleaning and disinfecting systems, and carrying out regular monitoring
Key Legionella control measures include: storing hot water at 60°C minimum (distributing at 50°C+ at outlets within 1 minute), keeping cold water below 20°C, flushing little-used outlets weekly, descaling showerheads quarterly, treating cooling towers with biocides, implementing a written scheme of control, regular temperature monitoring, and annual risk assessment review under L8/HSG274.
Question 6: What does the GHS pictogram showing a human silhouette with a starburst on the chest indicate?
- Irritant effects only
- Serious health hazards including carcinogenicity, mutagenicity, reproductive toxicity, respiratory sensitisation, or organ toxicity (Correct answer)
- Flammability
- Environmental hazard
Correct answer: Serious health hazards including carcinogenicity, mutagenicity, reproductive toxicity, respiratory sensitisation, or organ toxicity
The 'health hazard' pictogram (silhouette with starburst/exploding chest) indicates serious or chronic health effects including: carcinogenicity, mutagenicity, reproductive toxicity, respiratory sensitisation, specific target organ toxicity (single or repeated exposure), and aspiration hazard. This is distinct from the exclamation mark pictogram which covers less severe effects like skin/eye irritation.
NEBOSH Chemical and Biological Hazards 3
What is the purpose of a COSHH assessment under Regulation 6?