Carbon Monoxide Poisoning Claims
Carbon monoxide is invisible, odourless, and deadly. Every year in the UK around 50 people die from carbon monoxide poisoning and around 4,000 are admitted to hospital — almost all from preventable sources: faulty boilers, blocked flues, badly maintained gas appliances, and shoddy installation work. When a landlord, gas engineer, manufacturer, or installer fails in their legal duties and someone is injured by carbon monoxide as a result, the law allows a compensation claim.
In this guide
- What Is Carbon Monoxide Poisoning?
- Who Is Legally Responsible?
- Common Sources of Carbon Monoxide
- What Compensation Could You Receive?
- Time Limits for Carbon Monoxide Claims
- Evidence That Strengthens a Carbon Monoxide Claim
- Why Long-Term Assessment Matters
- No Win No Fee Carbon Monoxide Claims
- Support Beyond the Claim
- Common Questions About Carbon Monoxide Claims
- Related Guides
- Our Partner's Fees Explained
- Check If You Could Claim Compensation For Your Injury
This guide explains who can claim, who is responsible, what compensation typically covers, and how to start a claim on a no win no fee basis.
What Is Carbon Monoxide Poisoning?
Carbon monoxide (CO) is a gas produced when carbon-based fuels — gas, oil, coal, wood — burn incompletely. In a properly maintained appliance with adequate ventilation and a working flue, the gas is safely vented to the outside. In a defective or poorly maintained appliance, CO can build up inside the home, where it binds to red blood cells more strongly than oxygen does and causes oxygen deprivation throughout the body.
The symptoms of carbon monoxide poisoning are often mistaken for flu, a viral infection, or simple fatigue:
- Headache (the most common symptom)
- Dizziness
- Nausea or vomiting
- Fatigue and weakness
- Confusion or difficulty thinking
- Loss of consciousness in severe cases
- In extreme cases — coma, brain damage, and death
A key clue that symptoms are caused by CO and not flu is that they often improve when the affected person is away from the home (for example at work or on holiday) and return when they come back. Multiple people in the same household becoming unwell at the same time is another classic warning sign.
Long-term consequences of carbon monoxide exposure can include permanent neurological damage, cognitive impairment, memory problems, depression, and chronic fatigue — even where the initial exposure did not result in loss of consciousness.
Who Is Legally Responsible?
Carbon monoxide claims can be brought against any of the following, depending on the source of the leak:
Landlords
Under the Gas Safety (Installation and Use) Regulations 1998, landlords must:
- Have all gas appliances and flues inspected and tested annually by a Gas Safe registered engineer
- Provide tenants with a Gas Safety Certificate (CP12) within 28 days of inspection
- Keep records of safety checks for at least two years
- Ensure all gas work is carried out by a Gas Safe registered engineer
- Repair or replace any unsafe appliances
Since 2015 the Smoke and Carbon Monoxide Alarm (England) Regulations 2015 (as amended in 2022) have also required landlords in England to install a CO alarm in any room used as living accommodation containing a fixed combustion appliance. Similar regulations apply in Scotland and Wales. A landlord’s failure to comply with these duties is strong evidence of breach for a personal injury claim.
Gas Engineers and Heating Companies
Gas Safe registered engineers owe a duty of care to anyone who uses the appliance they have installed or serviced. A poorly fitted boiler, an incorrectly connected flue, or a missed defect during service can all support a claim.
Appliance Manufacturers
Where the appliance itself has a defect, the manufacturer can be sued under the Consumer Protection Act 1987 (see our defective product injury claims guide). Several major boiler manufacturers have run product recalls over CO-related defects.
Hotels, Holiday Lets and Other Accommodation Providers
Occupiers of holiday and short-stay accommodation owe duties under the Occupiers’ Liability Act 1957. CO incidents at holiday cottages, B&Bs, and rental properties are not uncommon, particularly with older heating systems. For incidents abroad on package holidays, claims can usually be brought in the UK courts — see our package holiday accident claims guide.
Workplaces
Employers owe duties under the Health and Safety at Work etc. Act 1974 and the Workplace (Health, Safety and Welfare) Regulations 1992. Industrial workplaces with combustion processes (commercial kitchens, garages, manufacturing premises) require specific CO management.
Common Sources of Carbon Monoxide
The most common sources in UK CO claims are:
- Gas boilers with blocked flues or defective heat exchangers
- Gas fires (particularly older convector models) installed without adequate ventilation
- Solid fuel stoves and open fires with blocked or damaged chimneys
- Gas cookers used as a heat source or with damaged burners
- Oil-fired boilers with damaged flues
- LPG appliances (particularly in caravans, mobile homes, and boats)
- Petrol-driven generators, pumps, and tools used indoors
- Disposable BBQs taken into tents or caravans
- Diesel-powered space heaters in industrial settings
For incidents involving disposable barbecues, generators, or other portable equipment, the claim may be against the manufacturer (for inadequate warnings) or against an accommodation provider who failed to address the risk. Specialist solicitors will identify the right defendant.
What Compensation Could You Receive?
Carbon monoxide poisoning compensation depends entirely on the severity of the exposure and the long-term effects:
- Mild exposure with full recovery within weeks — typically £3,000 to £10,000
- Moderate exposure with several months of fatigue, headaches, or cognitive symptoms — typically £15,000 to £40,000
- Significant lasting effects — including chronic fatigue, cognitive impairment, or psychological injury — typically £30,000 to £100,000
- Severe brain injury from major CO exposure (often after loss of consciousness or near-fatal exposure) — typically £80,000 to £493,000+
- Fatal CO poisoning — bereavement award plus loss of dependency under the Fatal Accidents Act 1976
Special damages cover lost earnings, private medical treatment, neurological rehabilitation, psychological treatment, and (for severe cases) lifetime care needs. Many CO survivors find that subtle cognitive and neuropsychological effects persist well beyond the acute illness — making a careful neurological and neuropsychological assessment essential to proper valuation.
Time Limits for Carbon Monoxide Claims
You have three years from the date of the poisoning, or from your date of knowledge that your symptoms were caused by CO exposure. The date of knowledge is often well after the original exposure — many CO incidents are initially misdiagnosed as flu, depression, or stress, and the true cause is only identified later (sometimes after subsequent occupants of the same property fall ill). For children, the three-year clock does not start until their 18th birthday. See our time limits guide for the full rules.
Evidence That Strengthens a Carbon Monoxide Claim
A solicitor will obtain everything you need. Strong claims usually include:
- Hospital records confirming the diagnosis (typically a raised carboxyhaemoglobin (COHb) blood level)
- GP records showing the symptom pattern
- For a rented property — the Gas Safety Certificate history (or its absence)
- Photographs of the appliance, the flue, and any CO alarm (or the absence of one)
- The HSE Gas Safety report, if the incident was investigated
- Engineer’s reports following the incident — including any “immediately dangerous” or “at risk” classification
- Records of any previous symptoms in occupants of the same property
- The landlord’s correspondence and any tenancy agreement
- Specialist neurological and neuropsychological assessments documenting long-term effects
For incidents involving rented property, an HSE investigation is often triggered automatically. The HSE report and any prosecution evidence are powerful evidence in a subsequent civil claim. Our evidence guide explains the wider picture.
Why Long-Term Assessment Matters
Carbon monoxide poisoning can leave subtle but real long-term effects that are not always picked up on routine medical assessment. These include:
- Memory and concentration difficulties
- Slower processing speed
- Mood changes — particularly depression and anxiety
- Chronic fatigue
- Headaches and migraines
- In severe cases, Parkinsonism or other movement disorders
A specialist solicitor will instruct a consultant neurologist and a clinical neuropsychologist to identify and quantify any long-term effects. Without this, the claim may be valued too low. CO claims with proper neuropsychological evidence often settle for multiples of the figure they would have settled for with a routine medical-records review alone.
No Win No Fee Carbon Monoxide Claims
Carbon monoxide claims run on a no win no fee Conditional Fee Agreement. You pay nothing upfront, nothing during the case, and nothing if the claim fails, provided you keep to the terms of your agreement. If the claim succeeds, the success fee — capped by LASPO 2012 at 25 per cent of general damages and past losses (future losses excluded) — is deducted from your compensation. After-the-Event insurance protects you from the other side’s costs if the case is lost. The ATE premium is normally payable only if you win, deducted from your compensation — it is no longer recoverable from the defendant — and your solicitor must explain how the premium and disbursements are treated before you sign (see how ATE insurance works). See our how no win no fee works guide.
Support Beyond the Claim
Several UK organisations provide support and information for people affected by carbon monoxide:
- CO-Gas Safety — campaigning charity offering information and advice
- Gas Safe Register — official body listing competent gas engineers and providing safety information
- Headway — for people with brain injury resulting from severe CO exposure
- Citizens Advice — for housing-related issues with landlords
Common Questions About Carbon Monoxide Claims
I think my landlord’s boiler made me ill but I never saw an actual leak. Can I still claim?
Yes. CO claims rarely involve a dramatic “leak” event — most involve gradual exposure to elevated CO levels over weeks or months from a poorly maintained or defective appliance. The case is built on medical evidence (raised COHb levels, neurological assessment), engineering evidence (the condition of the appliance and flue), and the landlord’s failure to comply with gas safety duties. A solicitor will obtain all of this.
My landlord did have a Gas Safety Certificate. Does that defeat my claim?
Not necessarily. Certificates can be issued by engineers who did not perform a thorough check, or before the appliance became defective. The case is built on the actual condition of the appliance at the time of the incident, not just the paperwork. A subsequent engineer’s report finding the appliance “immediately dangerous” carries far more weight than a tick-box certificate from six months earlier. The certificate may also have been from a non-Gas Safe registered engineer (a separate breach).
My children were also exposed. Can the family claim together?
Yes. Each affected member of the household can claim separately, and the claims are usually run together by the same solicitor. Children’s cases are particularly important because developing brains can be more vulnerable to CO damage, and children’s claims may not be fully valued for years until their development can be properly assessed. The three-year time limit does not start until each child’s 18th birthday.
I was exposed to CO at a holiday cottage. Can I claim?
Yes. The occupier of the holiday property owes you a duty of care under the Occupiers’ Liability Act 1957 (or equivalent legislation if the property is abroad). For overseas package holidays, the package operator is the appropriate defendant and the claim is brought in the UK under the Package Travel Regulations. See our package holiday claims guide.
How long does a carbon monoxide claim take?
Straightforward cases that the defendant accepts liability on can settle within 12 to 18 months. More complex cases — particularly those involving disputed long-term effects or significant brain injury — can take 2 to 4 years. Specialist neuropsychological evidence often takes 12 to 18 months to complete properly. See our how long does a claim take guide.
My family member died from carbon monoxide poisoning. Can the family claim?
Yes. The claim is brought through the estate (the executor) and dependants (spouse, children, financially-dependent partners and family members) can claim loss of dependency under the Fatal Accidents Act 1976. The bereavement award is currently £15,120 in England & Wales for spouses and parents of unmarried under-18s. Fatal CO cases involving rented property almost always result in HSE prosecution, which strengthens the civil claim. See our fatal accident compensation guide.
Related Guides
Accidents at Home — UK Compensation Guide
Defective Product Injury Claims
Package Holiday Accident Claims
Fatal Accident & Wrongful Death Compensation Claims
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