The serious hazards inside a British home are few, and most cannot be seen or smelt. Radon, a natural radioactive gas, is linked to about 1,100 deaths from lung cancer in the United Kingdom each year. Carbon monoxide from a faulty boiler, fire or stove can kill in hours. Asbestos and lead remain in many older houses.
Each has a straightforward test or precaution. Older accounts that warn instead of "toxins" in air fresheners and cleaning products have the proportions the wrong way round.
Radon is a colourless, odourless radioactive gas that forms naturally in all rocks and soils and seeps into buildings from the ground. The UK Health Security Agency attributes about 1,100 lung cancer deaths a year in the United Kingdom to it. The agency describes the risk to any individual as low, and it is highest for smokers and former smokers.
Levels depend on local geology. The agency and the British Geological Survey publish a map of radon potential for England, Scotland and Wales, last revised in December 2022, and a separate map covers Northern Ireland. Parts of the country with a raised probability of high levels are designated Affected Areas; most buildings are outside them. The maps are at ukradon.org.
A map shows probability, not the level in a particular house. That is found by a test: two small detectors, one in a bedroom and one in a living room, are left in place for three months and posted back for analysis.
High levels are brought down by building work — most often a small sump beneath the floor with a fan that draws the gas away, or improved ventilation under a suspended floor.
Carbon monoxide is produced when gas, oil, coal or wood burns without enough air, in a boiler, fire, stove or cooker that is faulty, badly fitted or has a blocked flue. It has no smell. The early symptoms are headache, dizziness, nausea and tiredness, resembling flu without a temperature; they ease away from the house and affect everyone in it, pets included.
The law on alarms differs between the four nations:
Anyone who suspects a gas leak or carbon monoxide opens the windows, leaves the building and calls the gas emergency number, 0800 111 999 in Great Britain.
The Health and Safety Executive states that asbestos can be present in any building built or refurbished before 2000. In houses it is found in textured ceiling coatings, old floor tiles, cement sheets on garages and sheds, and insulation round old boilers and pipes. It is dangerous only when damaged or disturbed. Material in good condition is left alone, and nothing suspected of containing it is drilled, sanded or broken up. The decorating aspect is covered under lead paint, asbestos and paint disposal.
Lead reaches people in old houses by two routes. Paint applied before the 1960s may contain it, and is dealt with on the same page as asbestos. Water pipes were made of lead until its use for the purpose ended in 1970, and houses older than that may still have a lead supply pipe: dull grey, soft enough to mark with a coin, with swollen joints. The water company can test the water at the tap.
Burning wood and coal indoors releases fine particles into the room and the neighbourhood. In a smoke control area only authorised fuels, or exempt appliances, may be used. Dry wood burns far more cleanly than wet, and stoves sold new have had to meet tighter emission limits since 2022.
Mould is a health hazard in its own right, and the commonest of all. It is covered under damp and mould.
Lists of "cancer-causers in the home" tend to give air fresheners and cleaning sprays equal billing with radon. The evidence does not. Scented products and sprays add volatile compounds to indoor air, and the practical answer is to use less and open a window. Chemical products are a real danger in a different way — by being swallowed by children, or mixed — which is covered under household cleaning products.