Work Equipment & Hazardous Substances

Under PUWER, work equipment provided on site must be...

• Apurchased new rather than hired in for each site
• Bcertified by the HSE before its first use on site
• Cinspected every day by the manufacturer's engineer
• Dsuitable, maintained and used by trained people✓

Answer: PUWER requires equipment to be suitable for its purpose, kept in efficient working order and used only by people with adequate training and information. Hired equipment is acceptable if it meets those tests, inspection is for the user to organise at a frequency matching the risk, and the HSE does not certify equipment.

An abrasive wheel is to be changed on a cut-off saw. Who may fit the new wheel?

• AAny operative who holds a current CSCS card
• BA person trained to mount abrasive wheels✓
• CAny operative supervised by a ganger
• DThe site manager as the person in control

Answer: PUWER requires anyone who mounts abrasive wheels to have been trained in the task, because a wrongly mounted or wrong-speed wheel can burst at high speed. A CSCS card, seniority on site or general supervision does not provide that specific training.

What is the danger if a cutting disc marked for a lower speed is fitted to a cut-off saw with a higher spindle speed?

• AThe disc will not fit because the bore is too small
• BThe disc can burst, throwing fragments at the user✓
• CThe disc cuts too slowly and overheats the motor
• DThe disc wears out sooner but is otherwise safe

Answer: Every abrasive disc is marked with a maximum operating speed, and running it faster than that can shatter it, sending fragments outwards with enough energy to kill. Motor overheating and faster wear are not the failure mode, and bore size is unrelated to the speed rating.

Which is the correct order of the COSHH hierarchy of control, from first choice to last resort?

• ASubstitute, eliminate, PPE, enclose or extract, then minimise
• BPPE, minimise, enclose or extract, substitute, then eliminate
• CEnclose or extract, eliminate, substitute, PPE, then minimise
• DEliminate, substitute, enclose or extract, minimise, then PPE✓

Answer: COSHH requires exposure to be prevented where possible, so the hierarchy starts with eliminating the substance, then substituting a safer one, then engineering controls such as enclosure and extraction, then minimising exposure, with PPE and RPE only as a final resort. The other sequences either put PPE ahead of prevention or rank engineering controls above removing the hazard.

How is a supplier's safety data sheet for a hazardous product structured?

• A8 sections in an order the supplier chooses
• B20 sections in an order the supplier chooses
• C16 sections in a fixed, standard order✓
• D12 sections in a fixed, standard order

Answer: Safety data sheets follow the REACH format of 16 numbered sections, covering hazard identification, composition, first aid, handling, exposure controls and disposal in a fixed order, so a site manager can always find the same information in the same place. Sheets with fewer or more sections, or a supplier-chosen layout, are not compliant data sheets.

A labourer has been kneeling in wet concrete for an hour. What is the main COSHH hazard?

• AAbsorption of lead through the skin from the mix
• BIsocyanate sensitisation from the cement binder
• CSilica dust inhaled from the wet concrete surface
• DAlkaline burns to the skin from the wet cement✓

Answer: Wet cement is strongly alkaline and prolonged skin contact causes chemical burns that can go unnoticed until deep tissue damage has occurred, as well as dermatitis. Cement does not contain lead or isocyanates, and silica becomes a respiratory hazard when cured concrete is cut or drilled, not while it is wet.

Which substance in two-pack paints and spray foams is a leading cause of occupational asthma in construction?

• AIsocyanate hardeners✓
• BCrystalline silica dust
• CLead-based pigments
• DOrdinary Portland cement

Answer: Isocyanates in two-pack coatings, adhesives and spray foams are respiratory sensitisers and the leading cause of occupational asthma in the UK, which is why COSHH demands extraction, air-fed RPE and health surveillance where they are used. Silica causes silicosis rather than asthma, lead causes poisoning, and cement causes burns and dermatitis.

Where would a site manager find the Workplace Exposure Limit for a substance used on site?

• AHSE publication EH40✓
• BHSE publication HSG47
• CHSE publication GS6
• DHSE publication HSG144

Answer: EH40 is the HSE document that lists Workplace Exposure Limits for hazardous substances and is the reference that a COSHH assessment and any exposure monitoring must be compared against. HSG47 covers avoiding underground services, HSG144 covers workplace transport and GS6 covers overhead power lines.

A CLP pictogram on a container shows a skull and crossbones. What does it indicate?

• AA long-term hazard such as a carcinogen
• BA substance that irritates the skin or eyes
• CAcute toxicity, potentially fatal on exposure✓
• DA substance that corrodes skin or metal

Answer: The skull and crossbones is the CLP symbol for acute toxicity, meaning the substance can kill or cause serious harm after a single exposure by inhalation, skin contact or swallowing. Irritants carry the exclamation mark, corrosives the test-tube-on-hand symbol, and long-term hazards such as carcinogens and sensitisers the health-hazard silhouette.

When must a COSHH assessment for a new product be completed?

• AOnly if an operative feels unwell
• BAfter the first week of use on site
• COnce it has been used for a month
• DBefore the product is first used on site✓

Answer: COSHH requires an employer to assess the risks and decide on controls before work involving a hazardous substance starts, so that exposure is prevented or controlled from the outset. Assessing after a week or a month, or waiting for symptoms, means people have already been exposed without the controls the assessment would have identified.

A contractor hires a plate compactor for two weeks. Which statement about PUWER duties is correct?

• AThe site manager's duties end once the hire agreement is signed
• BPUWER does not apply to equipment hired for under a month
• CThe hire company's duties cover all inspections during the hire
• DThe contractor must still check and maintain it while in use✓

Answer: PUWER places duties on the employer whose people use the equipment, so hiring does not transfer responsibility for pre-use checks, defect reporting and maintenance while it is on site. The hire company must supply equipment in a safe condition, but there is no exemption for short hires and no point at which the site's duties end while the machine is in use.

A petrol-engined cutter is to be used in a basement with limited ventilation. What is the site manager's correct decision?

• AAllow the work provided the operative wears an FFP3 dust mask
• BSubstitute an electric or battery cutter to remove the CO risk✓
• CAllow the work for 20 minutes at a time with a break between
• DAllow the work with a fan on the stairs to move the exhaust fumes

Answer: Petrol engines produce carbon monoxide, which is colourless, odourless and can kill in an enclosed space within minutes, so COSHH's hierarchy points to elimination by using an electric or battery tool. A fan gives no assurance of adequate air changes, a filtering face mask does not remove gases, and short bursts still expose the operative and anyone else in the basement.