CSCS Dust, Fumes & Respiratory Risks Questions
Silica dust, fumes and respiratory protective equipment.
Dust, Fumes & Respiratory Risks — practice questions (untimed, instant feedback)
- 8 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 8 Dust, Fumes & Respiratory Risks questions and answers
These are the same 8 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. When cutting or grinding with a power tool, why must the dust be captured rather than left to enter the air?
Answer: Most such dust is harmful if it is breathed in
- A) Most such dust is harmful if it is breathed in (correct answer)
- B) The tool runs faster with dust extraction
- C) To save clean-up time
- D) It removes the need for a machine guard
Why: Construction dusts such as silica are harmful to breathe, so they must be collected at source.
2. What can bring on occupational asthma?
Answer: Inhaling harmful dust, fumes or vapours
- A) Inhaling harmful dust, fumes or vapours (correct answer)
- B) Being exposed to loud noise
- C) Contact with rat urine
- D) Skin contact with a hazardous substance
Why: Occupational asthma is caused by breathing in respiratory sensitisers — harmful dust, fumes or vapours.
3. Which of these best describes a 'respiratory sensitiser'?
Answer: A type of harmful dust or fume
- A) A type of harmful dust or fume (correct answer)
- B) An item of respiratory protective equipment
- C) A prescribed medical device for breathing problems
- D) The person responsible for protecting respiratory health
Why: A respiratory sensitiser is a harmful dust or fume that can trigger asthma when breathed in.
4. What is the main purpose of respiratory protective equipment (RPE)?
Answer: To stop the wearer breathing in harmful substances
- A) To improve visibility
- B) To add comfort
- C) To keep dust out of the eyes
- D) To stop the wearer breathing in harmful substances (correct answer)
Why: RPE protects the wearer from inhaling harmful dust, fumes and vapours.
5. When should a disposable dust mask be replaced?
Answer: When it is damaged or hard to breathe through
- A) After two weeks
- B) When it is damaged or hard to breathe through (correct answer)
- C) Once a month
- D) After each shift regardless
Why: Replace a disposable mask once it is damaged or breathing through it becomes difficult.
6. What is a limitation of a dust mask as RPE?
Answer: It cannot filter gases or vapours
- A) It protects eyes but not lungs
- B) It cannot filter gases or vapours (correct answer)
- C) It is reusable
- D) It is expensive
Why: Dust masks stop particles only — they do not filter gases or vapours.
7. What can happen if you don't wear RPE when working with asbestos?
Answer: Lung diseases such as asbestosis
- A) Hearing loss
- B) Skin cancer
- C) Lung diseases such as asbestosis (correct answer)
- D) Digestive problems
Why: Breathing asbestos fibres can cause asbestosis and mesothelioma.
8. An RPE with a P3 filter protects against what?
Answer: High levels of fine dust and mist
- A) High levels of fine dust and mist (correct answer)
- B) Only large particles
- C) Gases and vapours
- D) Noise
Why: A P3 filter handles high levels of fine, including toxic, dust and mist.
What this topic covers in the CSCS test
Construction dust is not a nuisance, it is a cause of lung cancer, silicosis, chronic obstructive pulmonary disease and asthma. HSE believes over 500 construction workers die from exposure to silica dust every year, which makes it the biggest risk to construction workers after asbestos. These diseases build up slowly, so by the time you notice the damage it is usually permanent.
- The three groups of construction dust: silica dust, wood dust and other general dust such as gypsum and limestone
- The diseases: silicosis, COPD, occupational asthma and lung cancer
- Respiratory sensitisers and how repeated exposure triggers occupational asthma
- Stopping dust at source using water suppression and on-tool extraction
- The difference between local exhaust ventilation and respiratory protective equipment
- Choosing RPE: assigned protection factors, FFP3 masks and P3 filters
- Face fit testing, working clean shaven, and checking and replacing masks
Key facts worth memorising
- Silica exposure limit
- Respirable crystalline silica has a workplace exposure limit of 0.1 mg per cubic metre as an 8 hour time weighted average, listed in HSE's EH40.
- Silica is in almost everything you cut
- Sandstone is more than 70% silica and granite is 15 to 30%, and silica is a major constituent of bricks, tiles, concrete and mortar.
- RPE for construction dust is APF 20
- The general level is an assigned protection factor of 20, for example an FFP3 disposable mask or a half mask with a P3 filter, meaning the wearer breathes one twentieth of the dust in the air.
- Fit tested and clean shaven
- Tight-fitting masks rely on a seal against the skin, so they must be face fit tested on the individual wearer and the wearer must be clean shaven.
- LEV protects everyone, RPE protects one person
- Local exhaust ventilation, including on-tool extraction, removes dust from the air at source, while RPE only protects the person wearing it and only while it is worn correctly.
- Extraction needs testing every 14 months
- An on-tool extraction system must have a thorough examination and test at least every 14 months, and filters must be changed as the supplier recommends.
What people get wrong
Wetting the material before you start is enough.
HSE says plainly that just wetting the material beforehand does not work. Water has to be supplied at the right rate for the whole time the cutting or grinding is going on.
A mask is the answer to dust.
RPE is the last line of protection. Stop or reduce the dust first by using a different material, a less powerful tool or a different method, then capture it with water or on-tool extraction, and be ready to justify relying on RPE alone.
If you cannot see dust there is none.
Respirable crystalline silica is too fine to see in normal lighting. The particles that travel deepest into your lungs are exactly the ones you cannot see.
A dust mask will protect you from fumes and vapours.
Particle filters stop dusts and mists only. Gases, solvent vapours and welding fume need the right filter type or air-fed equipment, so check what your RPE is rated for before you rely on it.
Answering these questions in the test
Dust and fume questions are usually about the order of controls, not about masks. The best answer stops the dust being created, the next best captures it at source with water or on-tool extraction, and RPE comes last. If two answers both mention a mask, the better one adds something about fit testing, being clean shaven, or checking the mask before use. Remember what a filter can and cannot do: particle filters stop dust and mist, not gases and vapours. And remember the timescale. If a question asks what happens after years of exposure, expect silicosis, COPD, asthma or cancer rather than an immediate injury, which is also why questions about reporting early symptoms and attending health surveillance have a correct answer of yes.
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/construction/healthrisks/hazardous-substances/construction-dust.htm
- hse.gov.uk/pubns/cis36.pdf
- hse.gov.uk/construction/healthrisks/cancer-and-construction/silica-dust.htm
- hse.gov.uk/pubns/priced/eh40.pdf
- hse.gov.uk/respiratory-protective-equipment/fit-testing-basics.htm
- hse.gov.uk/lev/index.htm
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Ready for the real thing?
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