Carbon Monoxide Compensation Calculator

How much compensation can I claim for carbon monoxide poisoning?

Carbon monoxide (CO) is an invisible, odourless gas produced by faulty gas appliances, blocked flues or poor ventilation. Because you cannot see or smell it, poisoning often happens gradually, with symptoms – headaches, nausea, dizziness, confusion – easily mistaken for flu or tiredness until levels become dangerous. If you were poisoned because a landlord failed an annual gas safety check, a gas engineer did negligent work, or an employer failed to maintain equipment, you may be able to claim compensation. There is no single dedicated Judicial College Guidelines chapter for "CO poisoning" – instead, claims are valued by reference to the type of injury the poisoning actually caused, most often toxic fume inhalation and chest or lung effects, or in serious cases, organ and brain injury. This calculator gives an estimated range for general damages based on published bands for toxic fume and chest-related injuries, plus lost earnings and medical costs. It is built for UK tenants, homeowners and employees who want a realistic starting figure before contacting a solicitor.

How the estimate is worked out

The calculator combines two elements:

• General damages – an indicative band for pain, suffering and loss of amenity, from mild exposure with a full recovery within days or weeks, through toxic fume inhalation with some temporary lung effects, up to serious chest or lung damage with ongoing disability. The most severe cases – involving lasting brain injury, major organ damage or fatal poisoning – are not given a fixed range here because they require individual expert valuation and can be worth substantially more.
• Special damages – your financial losses, principally lost earnings during time off work for treatment, monitoring or recovery, plus any medical, hyperbaric oxygen therapy or care costs.

Severity is usually assessed by your carboxyhaemoglobin (COHb) blood level at the time of treatment, whether you needed hospital admission or hyperbaric oxygen therapy, and whether any cognitive, cardiac or neurological effects persist after apparent recovery – delayed neurological effects can appear weeks after the initial poisoning, which is why ongoing symptoms should always be reported to a GP even after you feel better.

Worked example

Amir rented a flat where the landlord had not carried out the legally required annual gas safety check on the boiler for over two years. A cracked heat exchanger leaked carbon monoxide into the flat; Amir was hospitalised with a headache, vomiting and confusion, given oxygen therapy, and was 2 weeks off work on a salary of £26,000, with £300 of follow-up private specialist appointments. His case is classed as moderate (£5,910–£13,970 general damages). Adding roughly £1,000 in lost earnings and his £300 costs, his total estimated claim falls in the region of £7,210 to £15,270. Because his landlord had no valid gas safety record for the property, liability is likely to be straightforward to establish.

Who can claim?

You may have grounds for a claim if:

• You were exposed to carbon monoxide from a gas appliance, boiler, flue or chimney that a landlord, letting agent, employer or gas engineer had a legal duty to maintain or install safely.
• A landlord failed to arrange the annual gas safety check required by law, failed to fit or maintain a carbon monoxide alarm where required, or ignored reported symptoms or a faulty appliance.
• A Gas Safe registered engineer carried out negligent installation, servicing or repair work – for example, failing to check flue ventilation or condemning (or failing to condemn) a dangerous appliance correctly.
• You have medical evidence of poisoning, ideally a blood carboxyhaemoglobin (COHb) test taken at the time, hospital records, or a fire brigade/gas engineer report confirming a CO leak or fault.
• You are within the standard three-year time limit from the date of exposure or, for gradually worsening symptoms, from when you reasonably became aware they were linked to CO exposure.

Common mistakes that reduce a claim

The most common mistake is not seeking medical attention or a blood test at the time of exposure, which makes it much harder to prove the level of poisoning later. Always call 999 or attend A&E if you suspect carbon monoxide poisoning, request that a COHb blood test is taken, and report the fault to your landlord and, where relevant, the Gas Safe Register or your local council's environmental health team. Keep any correspondence about repair requests, the gas safety certificate (or lack of one), and evidence of a working or missing CO alarm – these documents are often decisive in establishing liability quickly.

What affects how much you're awarded

Blood carboxyhaemoglobin level and hospital treatment at the time are the primary drivers of severity classification. Whether hyperbaric oxygen therapy was needed generally indicates a more serious exposure. Ongoing or delayed neurological symptoms – memory problems, difficulty concentrating, personality changes or headaches persisting weeks or months after exposure – are a recognised and sometimes underappreciated feature of CO poisoning, and can significantly increase an award if properly documented by a neurologist or occupational health specialist. Psychological impact, including anxiety about returning to the property or a diagnosed condition such as PTSD following a near-fatal exposure, can also form a separate head of claim. Multiple occupants exposed in the same incident (for example a whole family) can each bring individual claims reflecting their own level of exposure and symptoms.

Landlord and gas engineer responsibilities

Landlords in England and Wales have a legal duty under the Gas Safety (Installation and Use) Regulations 1998 to have every gas appliance and flue they provide checked annually by a Gas Safe registered engineer, and to give tenants a copy of the safety record within 28 days of the check (or before a new tenancy starts). Under the Smoke and Carbon Monoxide Alarm (England) Regulations, landlords must also fit a carbon monoxide alarm in any room used as living accommodation containing a solid fuel appliance, and increasingly for other fuel-burning appliances too. A landlord who fails to carry out the annual check, ignores a reported gas smell or fault, or lets a property with a known dangerous appliance, is likely to be in breach of these duties. Gas Safe registered engineers are separately bound by their registration standards and can be held liable for negligent installation, servicing or inspection work that leads to a CO leak.

How the claims process works

Most carbon monoxide claims start with a free consultation with a personal injury or housing disrepair solicitor, usually offered on a no-win-no-fee (Conditional Fee Agreement) basis. Your solicitor will gather your medical records, the property's gas safety history (or lack of it), and any Gas Safe or fire service reports, then send a formal Letter of Claim to the landlord, letting agent, employer or engineer (and their liability insurer). Where a landlord has clearly failed to carry out the required annual gas safety check, liability is often accepted relatively quickly; more complex cases involving disputed causation or long-term neurological symptoms can take longer to resolve, sometimes over a year, to allow your prognosis to stabilise before final settlement.

Frequently asked questions

How much compensation can you get for carbon monoxide poisoning UK?

General damages for CO poisoning are typically valued by reference to the type of injury caused, roughly from around £1,000 for mild, fully-resolved exposure up to £60,840 or more for serious chest/lung damage with ongoing disability. Cases involving lasting brain injury, major organ damage or death are assessed individually and can be worth substantially more. Lost earnings and medical costs are added on top.

Can I claim against my landlord for carbon monoxide poisoning?

Yes, if your landlord failed to arrange the legally required annual gas safety check, failed to fit or maintain a carbon monoxide alarm where required, or ignored a reported fault or gas smell. Landlords have a clear legal duty under the Gas Safety (Installation and Use) Regulations 1998, so a missing or overdue safety check is strong evidence of a breach of duty.

What should I do immediately if I suspect carbon monoxide poisoning?

Get fresh air immediately, turn off the suspected appliance if safe to do so, and call the Gas Emergency Freephone number or 999/A&E if you feel unwell. Ask for a blood carboxyhaemoglobin (COHb) test as soon as possible, as this is important medical evidence for a later claim, and report the fault to your landlord and the Gas Safe Register.

Do I need proof of a CO leak to make a claim?

Strong evidence includes a blood COHb test, hospital records, a Gas Safe engineer's report confirming a fault or leak, a missing or expired gas safety certificate, and any correspondence where you reported symptoms or a suspected gas problem. A solicitor can help gather this evidence, including from the local council's environmental health team if they investigated.

What is the time limit for a carbon monoxide compensation claim?

Generally three years from the date of exposure. Where symptoms developed or were recognised gradually, the three-year period may run from the date you reasonably became aware your symptoms were linked to carbon monoxide exposure rather than the exposure date itself.

Can I claim if the poisoning happened in a holiday let or hotel?

Yes. The operator of a holiday let, hotel or rented accommodation owes a duty of care to guests and tenants regarding the safety of gas appliances, similar to a residential landlord. Claims can be brought against the property owner, operator or letting agent depending on who was responsible for maintenance.

Will I need an independent medical report?

In most cases, yes, particularly if you have ongoing symptoms. An independent medical expert (often in occupational medicine, neurology or respiratory medicine, depending on your symptoms) will review your case and confirm the extent and likely cause of your injuries, which is essential for valuing the claim accurately.

Source: Gas safety duties from HSE – Gas safety in the home and Gas Safe Register; symptoms and treatment from NHS.UK – Carbon monoxide poisoning; general damages bands reflect published solicitor guidance on Judicial College Guidelines awards for toxic fume inhalation and chest injuries, see Judicial College – Guidelines for the Assessment of General Damages. Figures are indicative estimates – every case differs, seek advice from a regulated solicitor.