CITB Hazardous Substances 1 — Questions and Answers
Question 1: Which regulations require employers to assess risk from hazardous substances and implement control measures?
- The Dangerous Substances and Explosive Atmospheres Regulations 2002
- The Control of Substances Hazardous to Health Regulations 2002 (COSHH) (Correct answer)
- The Chemicals (Hazard Information and Packaging for Supply) Regulations 2009
- The Health and Safety (First-Aid) Regulations 1981
Correct answer: The Control of Substances Hazardous to Health Regulations 2002 (COSHH)
COSHH 2002 requires employers to assess exposure to hazardous substances, prevent or adequately control exposure, and monitor health where necessary.
Question 2: What does a Safety Data Sheet (SDS) provide?
- The purchase price and supplier contact details only
- Detailed information on a substance's hazards, safe handling, storage, first aid, and emergency measures (Correct answer)
- Legal confirmation that the substance is safe to use
- The manufacturer's quality certification
Correct answer: Detailed information on a substance's hazards, safe handling, storage, first aid, and emergency measures
An SDS provides comprehensive hazard information required under COSHH and REACH regulations, covering identity, hazards, handling, storage, exposure controls, and emergency response.
Question 3: What health risk does prolonged exposure to respirable crystalline silica (RCS) dust pose?
- Skin sensitisation and dermatitis
- Silicosis — irreversible, potentially fatal scarring of the lungs (Correct answer)
- Hearing loss
- Vibration white finger
Correct answer: Silicosis — irreversible, potentially fatal scarring of the lungs
Respirable crystalline silica generated by cutting stone, brick, or concrete penetrates deep into the lung tissue, causing silicosis — a progressive, incurable disease that can be fatal.
Question 4: Under COSHH, what is the preferred approach to controlling exposure to hazardous substances?
- Provide respiratory protective equipment (RPE) as the first control
- Substitute the hazardous substance with a less hazardous alternative, or eliminate it entirely (Correct answer)
- Rotate workers so no individual exceeds the WEL
- Post warning signs near the hazardous substance
Correct answer: Substitute the hazardous substance with a less hazardous alternative, or eliminate it entirely
COSHH follows the hierarchy of controls: eliminate, substitute, enclose, ventilate, control at source, reduce exposure time, PPE — substitution is preferred over exposure controls and RPE.
Question 5: What is a Workplace Exposure Limit (WEL)?
- The concentration at which a substance becomes flammable
- The maximum airborne concentration of a hazardous substance to which workers must not be exposed over a specified period (Correct answer)
- The maximum weight of a hazardous substance that can be stored on site
- The minimum PPE standard required when working with chemicals
Correct answer: The maximum airborne concentration of a hazardous substance to which workers must not be exposed over a specified period
WELs are set by the HSE in EH40 and represent the maximum concentrations of airborne substances to which workers may be exposed, typically as 8-hour time-weighted averages or short-term exposure limits.
Question 6: Which common construction chemical is classified as a sensitiser that can cause occupational asthma?
- Diesel exhaust fumes
- Isocyanates found in two-pack paints, adhesives, and spray foam (Correct answer)
- Mineral water used for mixing
- Sand used as a building aggregate
Correct answer: Isocyanates found in two-pack paints, adhesives, and spray foam
Isocyanates are a leading cause of occupational asthma in construction workers — once sensitised, even tiny exposures can trigger severe and potentially life-threatening asthmatic reactions.
CITB Hazardous Substances 1
Which regulations require employers to assess risk from hazardous substances and implement control measures?