CSCS Hazardous Substances (COSHH) Questions
COSHH assessments, asbestos and lead awareness.
These questions cover hazardous substances (coshh) for the CITB Health, Safety and Environment (HS&E) test, the exam UK construction workers pass to get a CSCS card.
Hazardous Substances (COSHH): practice quiz
- 20 questions · 30 minutes · pass mark 90%
- Answers and explanations are shown at the end, with every question to review.
- A fresh 20 questions every time, drawn from all 132 in this topic's bank. Includes 2 select-two questions and 4 picture questions, as in the real test.
- About 90 seconds a question, against about 54 in the real test, so there is time to think.
10 sample Hazardous Substances (COSHH) questions and answers
These 10 come from the 132 questions the practice quiz above draws from, written out with the correct answer and the reasoning behind it. Read them through when you want to revise rather than test yourself.
1. Under COSHH, what must an employer do before work liable to expose employees begins?
Answer: Make a suitable and sufficient assessment and implement the steps found
- A) Issue respiratory protective equipment to everyone who will be present
- B) Obtain written consent from the employees who will handle the substance
- C) Notify the Health and Safety Executive of the substances being used
- D) Make a suitable and sufficient assessment and implement the steps found (correct answer)
Why: Regulation 6(1) bars the work unless the employer has both made a suitable and sufficient assessment and implemented the steps it identified. Assessing without acting does not satisfy it.
2. When is health surveillance appropriate under COSHH?
Answer: Where an identifiable disease may be related to the exposure and is likely
- A) Whenever a hazardous substance may be present anywhere on the site
- B) Where an identifiable disease may be related to the exposure and is likely (correct answer)
- C) Only for employees who have already reported symptoms to their employer
- D) Only where the employer chooses to offer it as a workplace benefit
Why: Regulation 11(2) treats surveillance as appropriate for Schedule 6 substance and process combinations, or where an identifiable disease or adverse health effect may be related to exposure and is reasonably likely to occur.
3. Health surveillance results feed into what?
Answer: The risk assessment, which must consider relevant surveillance results
- A) The risk assessment, which must consider relevant surveillance results (correct answer)
- B) Only the individual worker's own medical file, kept confidentially
- C) Only a report to the enforcing authority at the end of the project
- D) Nothing, because surveillance happens after the assessment is complete
Why: Regulation 6(2)(h) requires the assessment to consider the results of relevant health surveillance, so a detected effect must feed back into the controls.
4. When does a COSHH assessment need to be reviewed?
Answer: When it is no longer valid or there has been a significant change
- A) Never, once it has been signed off by the employer at the very outset
- B) Only when a new substance is introduced onto the construction site
- C) When it is no longer valid or there has been a significant change (correct answer)
- D) Only when an employee reports symptoms related to the exposure at work
Why: COSHH follows the same review logic as the other risk assessment duties: an assessment that no longer reflects the work is not suitable and sufficient.
5. What do GB CLP hazard pictograms on a chemical label look like?
Answer: A diamond with a red border and a white background
- A) A diamond with a red border and a white background (correct answer)
- B) A yellow triangle with a black border and black symbol
- C) An orange square with a black symbol in the middle
- D) A blue circle with a white symbol in the centre
Why: HSE states that GB CLP hazard pictograms are diamond shaped with a distinctive red border and a white background. The orange square was the older European symbol style.
6. Which HSE publication contains the list of GB workplace exposure limits?
Answer: EH40, whose list is legally binding under COSHH
- A) INDG136, the brief guide to COSHH
- B) HSG65, the guide to managing health and safety
- C) EH40, whose list is legally binding under COSHH (correct answer)
- D) L5, the COSHH Approved Code of Practice
Why: HSE states that EH40 Workplace exposure limits contains the list of all current GB WELs and that the list is legally binding under COSHH.
7. When deciding who might be harmed by a hazardous substance, who does HSE remind you not to forget?
Answer: Maintenance workers, contractors, visitors and members of the public
- A) Nobody else, as only the workers who handle the product can be harmed
- B) Only the workers who have signed the method statement for the task
- C) Office staff, as site workers are covered by their own PPE
- D) Maintenance workers, contractors, visitors and members of the public (correct answer)
Why: HSE's COSHH assessment guidance says to think about anyone else who could be exposed and not to forget maintenance workers, contractors, other visitors or members of the public.
8. Exposure to a biological agent cannot be prevented. What can COSHH require for employees who are not already immune to it?
Answer: That effective vaccines are made available where appropriate
- A) That they are moved off site until the work is completely over
- B) That they sign a form accepting the risk of catching the illness
- C) That they take a course of antibiotics before starting the job
- D) That effective vaccines are made available where appropriate (correct answer)
Why: Regulation 7(6)(f) requires, where appropriate, making effective vaccines available to employees who are not already immune to the biological agent they are or may be exposed to.
9. HSE recommends an 'APC' approach to preventing dermatitis. What does APC stand for?
Answer: Avoid, protect, check
- A) Avoid, protect, check (correct answer)
- B) Assess, prevent, control
- C) Alert, protect, clean
- D) Avoid, plan, cover
Why: INDG233 sets out the APC approach: avoid contact with materials that cause dermatitis where possible, protect the skin, and check for early signs of dermatitis.
10. Why is using a solvent-based product in an enclosed space with little air movement so dangerous?
Answer: Solvent vapour can build up in the air, and this can be fatal
- A) Solvent vapour can build up in the air, and this can be fatal (correct answer)
- B) The product will not stick properly unless there is a draught
- C) Solvents give off vapour when used in the open, not indoors
- D) The vapour turns into a dust that coats the walls and floor
Why: HSE warns that lack of adequate ventilation can lead to a build-up of solvent in the air, creating a significant inhalation risk that can be fatal.
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.
Background reading
Drilling the questions tells you what you are getting wrong. It does not always tell you why. For this topic that is covered in COSHH Symbols. All nine of them, what each one warns you about, and why they are not really COSHH symbols at all.
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 CSCS mock test for Operatives under exam conditions, then how to book the CSCS test. Still under 90%? Keep your CSCS exam prep going with another topic.