CSCS Hazardous Substances (COSHH) Questions
COSHH assessments, asbestos and lead awareness.
Hazardous Substances (COSHH) — practice questions (untimed, instant feedback)
- 9 questions · pass mark 90%
- Untimed practice — you see the correct answer immediately after each question.
- Some questions need more than one answer — these are clearly marked.
All 9 Hazardous Substances (COSHH) questions and answers
These are the same 9 questions as the practice test above, written out with the correct answer and the reasoning behind it. Read them through when you want to revise rather than test yourself.
1. How can asbestos be reliably identified?
Answer: By having a sample tested in a laboratory
- A) By having a sample tested in a laboratory (correct answer)
- B) By seeing whether a piece dissolves in water
- C) From the colour of the dust
- D) By its strong smell
Why: Asbestos can only be confirmed by laboratory analysis of a sample — you cannot tell by sight or smell.
2. Before you use a hazardous substance, who should explain the health risks and the safe method of work (the COSHH assessment)?
Answer: Your supervisor or employer
- A) A Health and Safety Executive inspector
- B) The site's first aider
- C) Site security staff
- D) Your supervisor or employer (correct answer)
Why: Your employer or supervisor must brief you on the COSHH assessment before you start work with the substance.
3. A product carries a hazardous-substance label. How should you dispose of the container or any leftover residue?
Answer: Follow the instructions on the label or in your method statement
- A) Follow the instructions on the label or in your method statement (correct answer)
- B) Pour it down a drain if it is under a litre of liquid
- C) Leave it for someone else to sort out
- D) Drop it in any skip or bin
Why: Dispose of hazardous products as directed on the label or in your work instructions.
4. Working with which of these materials may need a COSHH assessment? (Choose all that apply)
Answers: Asbestos, Tile (for example, the dust from cutting it) and Wood (for example, wood dust)
- A) Asbestos (correct answer)
- B) Metal
- C) Plastic
- D) Tile (for example, the dust from cutting it) (correct answer)
- E) Wood (for example, wood dust) (correct answer)
Why: Asbestos, and the dust from cutting tile or wood, can all require a COSHH assessment.
5. What should you do first if a hazardous substance contacts your skin?
Answer: Wash the affected area thoroughly
- A) Drink water
- B) Wash the affected area thoroughly (correct answer)
- C) Sit down and rest
- D) Carry on working
Why: Wash the area at once to remove the substance and limit exposure.
6. What is the main purpose of the COSHH regulations?
Answer: To control substances hazardous to health
- A) To prevent pollution
- B) To ensure the right equipment is used
- C) To control substances hazardous to health (correct answer)
- D) To set fire-safety rules
Why: COSHH controls substances that are hazardous to health to prevent harm.
7. Which is a possible effect of exposure to a hazardous substance?
Answer: Skin irritation
- A) Better concentration
- B) Skin irritation (correct answer)
- C) A stronger immune system
- D) Increased strength
Why: Skin irritation is one of many possible health effects of exposure.
8. Under COSHH, who must assess the risk from hazardous substances?
Answer: The employer
- A) Employees
- B) The HSE
- C) The employer (correct answer)
- D) Visitors
Why: The employer is responsible for the COSHH risk assessment and controls.
9. Which hazard symbol indicates a toxic substance?
Answer: A skull and crossbones
- A) A green cross
- B) A skull and crossbones (correct answer)
- C) A flame
- D) A leaf
Why: The skull-and-crossbones symbol marks a toxic substance.
What this topic covers in the CSCS test
COSHH is the Control of Substances Hazardous to Health Regulations 2002. It covers chemicals, products containing chemicals, dusts, fumes, vapours, mists, gases and biological agents, and its objective is to prevent exposure or, where that is not reasonably practicable, to control it adequately. Most construction sites use dozens of substances that fall under it, from cement and resins to solvents and cutting dust.
- What counts as a substance hazardous to health, and which substances have their own separate regulations
- The routes by which a substance gets into your body
- Who must carry out the COSHH assessment and who must brief you on it before you start
- GB CLP hazard pictograms, product labels and safety data sheets
- Workplace exposure limits and where they are published
- Asbestos: where it is found, why it cannot be identified by eye, and the categories of work
- Control measures in order, from enclosure and extraction down to PPE, plus safe disposal of residues and containers
Key facts worth memorising
- Four routes of entry
- HSE describes exposure as uptake into the body by breathing in fume, dust, gas or mist, by skin contact, by injection into the skin, and by swallowing.
- Lead, asbestos and radioactive substances sit outside COSHH
- HSE states these three have their own specific regulations, so asbestos work is governed by the Control of Asbestos Regulations 2012 rather than by COSHH itself.
- Asbestos control limit
- The Control of Asbestos Regulations 2012 define the control limit as 0.1 fibres per cubic centimetre of air averaged over a continuous period of 4 hours.
- Licensed asbestos work
- Higher-risk work such as removing sprayed coatings, disturbing pipe lagging or handling loose fill insulation must be done by an HSE-licensed contractor and notified to the enforcing authority at least 14 days before it starts.
- Asbestos is still the biggest killer
- HSE says asbestos can be found in any building built before the year 2000, and 2,146 people died of mesothelioma in Great Britain in 2024 through past asbestos exposure.
- Workplace exposure limits
- Only about 500 substances have a workplace exposure limit; they are listed in HSE publication EH40 and that list is legally binding under COSHH.
What people get wrong
You can tell asbestos by looking at it.
You cannot. It is confirmed only by laboratory analysis of a sample. Treat any suspect material in a building built before 2000 as asbestos until it has been checked, and stop work and report it.
If you can buy it in a shop it does not need a COSHH assessment.
If the packaging carries a GB CLP hazard pictogram, a diamond with a red border on a white background, the product is classed as hazardous. Cement, resins, adhesives and solvents are everyday examples.
PPE is the main COSHH control.
PPE and RPE are the last line. COSHH expects you to prevent exposure first, then use control equipment such as enclosure or local exhaust ventilation, then good working procedures, and only then personal protection.
Leftover product and empty containers can go in the general skip.
Dispose of hazardous products and their residues as the label or your work instructions direct. Getting this wrong is both a health risk and an environmental offence.
Answering these questions in the test
COSHH questions reward two habits. First, look at the label: if a question mentions a hazard symbol or a data sheet, the correct answer almost always involves reading it, or asking for the COSHH assessment, before you start work. Second, remember who does what. The employer assesses the risk, provides the controls and briefs you on the safe method; you use the controls provided, follow the hygiene rules and report anything that looks wrong. Asbestos questions have a fixed shape: the right answer is to stop work, leave the area and report it, and never to sweep it up, break it, or take clothing home. Any option suggesting you can identify asbestos by sight or smell is wrong.
Sources
Written from the following. Where a figure could not be verified against one of these, it has been left out rather than approximated — our sources and methodology explains how we date and re-check them. Spotted something wrong? Report an error and we will fix it.
- hse.gov.uk/coshh/index.htm
- hse.gov.uk/coshh/basics/substance.htm
- hse.gov.uk/coshh/basics/control.htm
- hse.gov.uk/coshh/basics/exposurelimits.htm
- hse.gov.uk/chemical-classification/labelling-packaging/hazard-symbols-hazard-pictograms.htm
- hse.gov.uk/asbestos/index.htm
- hse.gov.uk/asbestos/licensing/licensed-contractor.htm
- legislation.gov.uk/uksi/2012/632/regulation/2/made
- hse.gov.uk/statistics/overview.htm
Topics that come up alongside hazardous substances (coshh)
Ready for the real thing?
When you are scoring 90% or better here, take a timed 50-question mock under exam conditions, then book your CITB HS&E test.