Gas leak: what to do if you smell gas

This guide is written to be read calmly now, not mid-emergency, and it adds nothing to the official advice: every step below is the published guidance of the National Gas Emergency Service, Gas Safe Register or the HSE, with the source named as you go. The shape to remember: fresh air, no flames, no switches, gas off only if safe, everyone out, 0800 111 999.

What should you do immediately if you smell gas?

Four steps, in the order the official advice gives them.

What should you not do while you can smell gas?

The do-nots matter as much as the dos, because gas needs only a spark. All of these are from the official smell-gas guidance:

• Do not smoke, strike matches or use any other naked flame, and put out candles and cigarettes as you leave.
• Do not turn electrical switches on or off: either direction can spark, so lights, appliances and doorbells stay exactly as they are.
• Do not use the appliance you suspect, and do not turn anything back on until the escape has been found and fixed.
• Do not stay inside hunting for the source. Finding the leak is the emergency engineer's job; yours is to be outside when they arrive.

Who do you call, and what does it cost?

The National Gas Emergency Service on 0800 111 999 covers suspected escapes on the mains gas network in England, Scotland and Wales, free and staffed 24 hours a day. It is the right number whoever your supplier is, because the emergency service attends regardless of who sends your bill. Northern Ireland has its own gas emergency number, 0800 002 001, and LPG properties call the supplier's emergency number shown on the tank, the cylinder store or the delivery paperwork. If there is a fire or anyone is in immediate danger, call 999 first.

What happens when the emergency engineer arrives?

The emergency service makes the situation safe; it does not do repairs. The attending engineer will trace and stop the escape, which can mean isolating an appliance or the whole supply, and will tell you what has been turned off and why. The repair itself is a separate job for a Gas Safe registered engineer, arranged by whoever is responsible for the property, and anything the emergency engineer isolated stays off until it has been repaired and recommissioned.

What if a carbon monoxide alarm sounds instead?

Same seriousness, same number. Carbon monoxide has no smell, so the alarm is the warning: get everyone into fresh air, turn the appliance off if you can do so safely, and call 0800 111 999. If anyone feels unwell, Gas Safe Register's advice is to go to a GP or hospital immediately and say you may have been exposed to gas or carbon monoxide; the NHS lists headache, dizziness, nausea, tiredness and confusion, stomach pain and shortness of breath as the symptoms to watch. Our carbon monoxide guide covers the alarm rules nation by nation.

What must landlords and tenants do about a leak in a rented home?

The emergency steps belong to whoever smells the gas; nothing about a tenancy changes them. What the tenancy changes is what happens next. The tenant's part is to report the leak, and anything the emergency engineer turned off, to the landlord or agent straight away, in writing. The landlord's part follows from the duty the HSE sets out under the Gas Safety (Installation and Use) Regulations 1998, to keep the property's gas appliances, pipework and flues maintained in a safe condition: arrange the repair promptly with a Gas Safe registered engineer, keep the tenant informed, and leave whatever was isolated exactly as the emergency engineer left it until the repair is done.

What should a gas engineer do when a customer reports a leak?

Give them the emergency number before anything else. A suspected escape left on an engineer's voicemail is not handled: the National Gas Emergency Service exists to attend escapes at once, so the professional move is to interrupt the story, say 0800 111 999, and talk about the repair afterwards. On site, an engineer who finds an escape or a dangerous fitting works to the industry's unsafe situations procedure, published by IGEM: classify what was found, seek the responsible person's permission to isolate, attach the warning notice and record it. RIDDOR sits behind the serious cases, since registered engineers have a duty to report certain dangerous gas fittings they encounter. Our warning-notices guide covers the classifications in detail.

How should the event be recorded once everyone is safe?

Record keeping is for afterwards; nothing in this section happens while you can smell gas. Once it is over, the paper trail is what shows the danger was dealt with: when the smell was reported, when the emergency service attended, what was isolated, who repaired it and when the appliance was recommissioned. For a landlord, that file answers the questions a council, insurer or tenant's adviser will later ask. For an engineer, the defect, the warning notice and the repair belong against the appliance, which is the one place Manifold belongs in this story: defects, warning notices and repairs sit on the property's history beside its gas safety records. The emergency itself needs no app at all, just fresh air, no sparks and a phone call.