Hazardous Substances

What does COSHH stand for?

• AChemicals and Occupational Safety Handling
• BControl of Substances Hazardous to Health Regulations 2002✓
• CControl of Serious Health Hazards
• DConstruction Operations Stress and Health Handbook

Answer: COSHH is the statutory framework regulating hazardous substances in workplaces. It requires assessments, exposure control, and employee information.

Under COSHH, what information must be provided with hazardous substances?

• ASafety Data Sheets (SDS) with health hazards, handling, and emergency procedures✓
• BOnly the cost
• COnly the date of purchase
• DOnly the supplier name

Answer: Regulation 4 COSHH requires Safety Data Sheets for all hazardous substances. SDS include hazard classification, exposure limits, and safe handling. Cost, purchase date, and supplier alone are insufficient.

Asbestos is a hazardous substance historically used in construction. Which statement is TRUE in the UK?

• ARemoval is a routine task for all construction workers
• BAsbestos use is unrestricted if workers are trained
• CAsbestos is safe at low exposures
• DAsbestos is banned for new use; only licensed specialists can handle existing asbestos✓

Answer: The Asbestos (Prohibitions) Regulations 2006 ban new asbestos use. Existing asbestos requires licensed contractors for removal. Non-licensed workers cannot disturb it.

Silica dust exposure on construction sites can cause:

• ATemporary irritation of the eyes only, which clears once the worker leaves the dusty area
• BHearing loss only
• CNo long-term health effects, because the particles are too large to reach the lungs
• DSilicosis, lung cancer, and other serious respiratory diseases✓

Answer: Crystalline silica dust (from cutting stone, sand blasting, etc.) causes silicosis and lung cancer. Health risks are severe and long-term. Temporary irritation is minor compared to chronic disease.

How should silica dust exposure be controlled on a construction site?

• AThrough elimination (wet cutting), good housekeeping, and RPE if needed✓
• BBy issuing every worker with a basic nuisance dust mask and carrying on with dry cutting
• CControl is unnecessary, because silica occurs naturally in the stone and sand on every site
• DBy letting workers build up a tolerance to the dust over their first few weeks on site

Answer: The hierarchy prioritises wet cutting to suppress dust, local extraction, enclosure, and finally appropriate RPE. Single-mask approach is inadequate. Acclimatisation does not occur with silica.

Lead is used in certain construction materials. What is the primary health risk from lead exposure?

• AIncreased energy levels
• BMinor skin rash
• CSerious damage to the nervous system, kidneys, reproductive system, and red blood cells✓
• DTemporary headaches that clear up within a day or two once the worker has left the work area

Answer: Lead is a potent neurotoxin. Chronic exposure damages neurological, renal, and reproductive systems and impairs haemoglobin production. Effects are cumulative and serious.

When should a COSHH assessment be carried out?

• AOnly if an incident occurs
• BAn assessment is unnecessary; a substance is safe to use as long as it carries a manufacturer's hazard label
• CBefore hazardous substances are used and whenever the work changes significantly✓
• DOnce a year, on a fixed date, regardless of what substances are actually being used

Answer: Regulation 6 COSHH requires assessment before use and when conditions change. Labels indicate hazards but do not replace workplace-specific risk assessment.

A chemical spill occurs on a construction site. What should NOT be done?

• AAttempt to sweep it up immediately without assessing the chemical✓
• BAlert nearby workers to the spill
• CUse the PPE and spill kit specified in the safety data sheet for that substance
• DReport the spill and follow the site emergency procedure for chemical releases

Answer: Sweeping an unknown chemical risks exposure and reaction. First assess the substance via its SDS, alert workers, use proper PPE and spill kits, and follow site procedures.

Which of the following substances requires a COSHH assessment on construction sites?

• AWater drawn from the site standpipe for mixing and for washing down
• BOnly substances whose containers carry a red hazard label of some kind
• CConcrete dust, solvents, adhesives, and paints✓
• DSand only, because it is the one material stored loose on most sites

Answer: Construction chemicals like dust, solvents, and adhesives are hazardous and require assessment. Water is non-hazardous; sand varies. Label colour is not the determining factor.

An employee becomes ill after exposure to a hazardous substance at work. What should the employer do?

• ATerminate the employee
• BDo nothing if the illness appears minor
• CAssume it is unrelated to work
• DSeek medical advice, review the COSHH assessment, and implement additional controls✓

Answer: Illness after exposure signals a control failure. The employer must investigate, review COSHH, seek medical guidance, and prevent recurrence. Dismissal and inaction are inappropriate responses.

What are Workplace Exposure Limits (WELs) under UK health and safety law for hazardous substances?

• AThe maximum quantity of a substance a worker is permitted to touch with bare hands during a shift, above which gloves have to be worn, expressed in grams for solids and millilitres for liquids
• BLegally set maximum air concentrations of hazardous substances workers can be exposed to over a working day (8-hour TWA) or short-term (15-minute STEL) without exceeding acceptable risk✓
• CExposure limits chosen by each individual employer for their own workforce and written into the company health and safety policy, which the Health and Safety Executive then registers on request
• DFigures produced by the insurance industry and applied to construction sites through the terms of employers' liability policies, rather than through any piece of health and safety legislation

Answer: WELs are statutory exposure limits (set by HSE, in regulations like Control of Substances Hazardous to Health Regulations 2002) based on health risk. They're not arbitrary, skin contact isn't relevant, and employers cannot set lower limits (though higher is prohibited).

Why is dust suppression critical in construction activities like grinding and cutting stone?

• ATo reduce the noise made by the cutting disc, because water running onto the blade damps the sound and lowers the level reaching the operator's ears and those of anyone working nearby
• BTo prevent inhalation of silica dust, which can cause chronic lung disease (silicosis); effective controls include water spraying, extraction, or enclosed methods✓
• CTo improve visibility on the work face only, since a cloud of dust makes it hard to follow a cutting line accurately and slows the work down more than it creates any risk to health
• DTo improve worker morale

Answer: Silica dust inhalation causes silicosis and lung cancer. Water suppression, LEV, and enclosure prevent inhalation. Visibility improves as a side benefit. Noise and morale are unrelated to the health hazard.

What does a Local Exhaust Ventilation (LEV) system do in a construction workshop?

• AIt supplies fresh air into the workshop through ducting in the roof, raising the number of air changes an hour so that the whole space is generally ventilated
• BCaptures hazardous dust, fumes, or vapours at source before they reach the worker's breathing zone; the contaminated air is filtered or expelled safely✓
• CIt removes only large debris such as offcuts, sawdust and swarf from the working area, drawing them into a collection bag so the floor stays clear underfoot
• DCools the air only

Answer: LEV source capture prevents hazardous inhalation. It differs from general ventilation (which dilutes but doesn't prevent exposure). Cooling, fresh air, and debris removal are separate functions.

Under the Control of Substances Hazardous to Health Regulations (COSHH) 2002, what must be done before introducing a hazardous substance on site?

• AAssess the hazards, determine exposure risk, and implement control measures; a Safety Data Sheet (SDS) must be obtained and understood by users✓
• BA substance that can be bought over the counter in a builders' merchant needs nothing done in advance, because retail products are outside the scope of the regulations
• CProvide the workers who will use it with a pair of chemical-resistant gloves, which on its own discharges the duty owed before the substance is brought onto the site
• DOnly store the substance safely

Answer: COSHH 2002 mandates hazard assessment, exposure evaluation, and control implementation before use. SDS review is essential. Storage and gloves alone don't fulfil duties; assessment is prerequisite.

What is health surveillance in the context of hazardous substance exposure in construction?

• AChecking equipment performance only
• BRegular health checks or monitoring (e.g., lung function tests, skin checks) to detect early signs of occupational disease from hazardous substance exposure✓
• CMonitoring how hard individual workers are working across the shift, so that output can be compared between operatives and any drop in performance investigated by the supervisor
• DRecording absence rates

Answer: Health surveillance involves medical monitoring (lung function, skin assessments, blood tests) to catch occupational disease early before serious harm occurs. Work monitoring, equipment checks, and absence rates are unrelated.

Why is dermal exposure (skin contact) with hazardous substances a significant concern in construction even if inhalation is controlled?

• AIt only matters for the small number of workers who already have sensitive skin or a history of eczema; everyone else is unaffected by contact with substances used on a construction site
• BSkin is a naturally waterproof barrier that keeps every industrial substance out of the body, so contact with the hands and forearms carries no risk as long as the skin is washed at the end of the shift
• CSome substances are readily absorbed through skin and can cause systemic toxicity; others cause dermatitis or sensitisation; skin damage compromises the barrier function✓
• DGloves are always adequate on their own, because any glove sold for construction work is tested against the full range of substances found on a building site, whatever the length of contact

Answer: Skin absorption can cause systemic poisoning (e.g., organic solvents). Dermatitis and sensitisation occur from skin contact. Damaged skin (cuts, eczema) increases penetration. Gloves are protective but not absolute; skin hygiene and exposure reduction are additional controls.

What is the purpose of a Safety Data Sheet (SDS) provided by the supplier of a hazardous substance?

• ATo provide warranty information
• BTo inform users of hazards, safe handling, emergency procedures, and disposal; required by REACH and COSHH regulations to enable risk assessment and control selection✓
• CTo prove the product is cheap
• DTo provide marketing information about the product, setting out its coverage, drying time and the finishes it can be used over, so that the buyer can compare it with competing brands

Answer: SDS (formerly MSDS) contains hazard classification, health effects, safe handling, emergency response, and disposal information. It's a regulatory document essential for COSHH assessment, not marketing or warranty material.

Under UK legislation, who is responsible for ensuring that construction workers are not exposed to asbestos during demolition work?

• AThe waste disposal company alone, which takes on the whole duty as soon as it collects the material from the site, meaning the demolition contractor has nothing to do about asbestos until the debris is ready to be removed
• BOnly if asbestos is visibly obvious
• CThe demolition contractor, in coordination with the Principal Contractor, must identify asbestos-containing materials, plan safe removal or encapsulation, and ensure licensed contractors conduct the work✓
• DThe worker themselves

Answer: The Control of Asbestos Regulations 2012 places duty on the contractor undertaking the work to plan and supervise safe asbestos management. Identification is essential before work; licensing is required for removal; waste disposal is part of the process. Worker effort and visibility alone don't protect.

Why might construction workers in spray painting operations require health surveillance?

• ATo check attendance only
• BBecause spray painting is obviously a dangerous job, and health surveillance is required for every task on a construction site that is generally regarded as dangerous by the workforce
• CTo monitor productivity
• DTo detect early signs of respiratory sensitisation or solvent toxicity from repeated exposure to paint mists and volatile organic compounds (VOCs)✓

Answer: Spray painting exposes workers to paint mists (containing sensitising agents like isocyanates in polyurethane coatings) and VOCs. Health surveillance detects sensitisation early. Productivity, attendance, and general 'danger' don't determine surveillance need—specific hazards do.

What must be included in a COSHH assessment for welding fumes in construction?

• AOnly the cost of equipment
• BOnly the type of metal being welded, since the parent metal alone determines what is given off; the process used, the consumables, the length of time spent welding and the ventilation in the space where the work is done all make no difference to the assessment
• CThe fume composition, concentration, duration and frequency of exposure, control measures (extraction, ventilation), and worker health effects (metal fume fever, chronic lung disease); exposure monitoring if levels are uncertain✓
• DOnly the welder's experience

Answer: COSHH assessment covers hazard identification (fume type and composition), exposure evaluation (concentration, frequency, duration), control selection (LEV, general ventilation), and health monitoring. Cost, experience, and metal type are parts but not the complete assessment.

How should a construction site manager reduce workers' exposure to concrete dust and respirable crystalline silica (RCS)?

• ABy using wet cutting methods, local extraction, damping down, or using pre-cut materials; in high-exposure tasks, respiratory protection should be supplementary✓
• BBy telling workers to work faster
• CBy refusing to allow the task to be carried out at all, without first considering whether wet cutting, extraction or pre-cut materials would bring the exposure down to an acceptable level
• DBy providing only extra breaks

Answer: Engineering controls (water suppression, LEV, pre-cut materials) are primary. RPE is supplementary when engineering controls are insufficient. Speed, breaks, and avoidance without attempting controls don't address the hazard systematically.