Carbon monoxide poisoning

Also called CO poisoning, The silent killer

Colourless, odourless, and it mimics flu. An alarm costs less than a takeaway and is the only way to detect it.

What it is

Poisoning by carbon monoxide, a gas produced when fuel burns incompletely. It has no colour, no smell and no taste, and it binds to haemoglobin far more strongly than oxygen does, so the blood stops carrying oxygen while the person feels only vaguely unwell.

Sources are faulty or badly ventilated boilers, gas fires, wood burners, solid fuel stoves, gas cookers, blocked flues, portable generators, barbecues brought indoors or into tents, and vehicle exhaust in enclosed spaces.

It kills people in the UK every year and hospitalises many more, and a large number of low-level exposures are never diagnosed at all, because the symptoms are indistinguishable from flu or a virus.

Two clues separate it from flu: **no fever**, and **everyone in the building feels ill, including pets, and everyone improves when they leave**. That pattern is the diagnosis until proven otherwise.

Long-term low-level exposure causes lasting problems with memory, concentration and mood, and is easily attributed to something else. Babies, children, older people, pregnant women and anybody with heart or lung disease are affected at lower concentrations.

An audible alarm to the current British Standard, in every room with a fuel-burning appliance, is the whole of prevention.

Signs you might notice

Headache, which is the commonest symptom.

Dizziness, nausea and vomiting, tiredness, confusion, breathlessness, stomach pain.

Symptoms that improve when away from the building and return on going back.

Several people or animals in the same household unwell at once.

No fever, and no sore throat or runny nose, which is what makes it not flu.

Later or severe: loss of coordination, chest pain, collapse, seizures, unconsciousness. The classic cherry-red skin is a late and unreliable sign.

If suspected: get everybody out into fresh air, do not go back in, turn off the appliance if it is safe to do so, and call 999 for anyone drowsy or unconscious. Report a gas emergency on 0800 111 999.

How it can affect day-to-day life

It is a housing problem as much as a health one, concentrated in poor-quality rented accommodation, older housing and homes where heating is being used in ways it was not designed for during cold weather and fuel poverty.

Landlords in England have a legal duty to provide working carbon monoxide alarms in rooms with fixed combustion appliances, and to keep them in repair. Tenants frequently do not know this.

In supported living and care settings, alarms and annual servicing are a straightforward safety check that is easy to let lapse.

Anybody presenting repeatedly with headaches over a winter deserves the question asked: does anybody else at home feel the same, and does it get better when you go out?

Supporting someone well

Fit an audible alarm to BS EN 50291 in every room with a fuel-burning appliance, and test it monthly. It is inexpensive and it is the only detection there is.

Have gas appliances serviced annually by a Gas Safe registered engineer, and solid fuel appliances and chimneys swept.

Never use a barbecue, camping stove or generator indoors, in a tent, awning or garage, even a cooling one.

Do not block air vents, and keep flues clear.

Ask the pattern questions when somebody has winter headaches: anyone else, and does it improve away from home.

If suspected: everybody out, doors open, do not re-enter, ring 0800 111 999, and 999 for anyone drowsy.

Tell any clinician you suspect it; a blood test measuring carboxyhaemoglobin is available but falls quickly once away from the source, so say it early.

Where to get help

999 for anyone drowsy, confused, collapsed or having a seizure.

The National Gas Emergency Service on 0800 111 999 for a suspected gas leak or faulty appliance.

A GP practice or NHS 111 for milder symptoms, saying carbon monoxide by name.

The local council's environmental health team where a landlord will not act.