Gas Escape and Emergency Procedures

A gas escape occurs when natural gas leaks from a damaged main, service pipe, or fitting, creating explosion and asphyxiation risk.
Natural gas (methane) is lighter than air and disperses upward, but can accumulate in enclosed spaces and buildings.
The distinctive smell of gas is added during processing — it is not a natural property and may not be present in all leaks.
If you smell gas or suspect a gas leak, the first action is to move away from the area and call the National Gas Emergency Service.
The National Gas Emergency number is 0800 111 999 — this number must be known by everyone working near gas infrastructure.
Do not create any ignition source near a suspected gas leak — this includes switching lights, using phones, and starting engines.
Evacuate the immediate area and establish a cordon preventing anyone from approaching the suspected leak location.
Do not attempt to stop the leak yourself — gas company engineers with specialist equipment must handle the emergency.
Ventilate any enclosed space where gas may have accumulated by opening doors and windows if it is safe to approach.
Striking a gas main during excavation is the most common cause of gas escapes on construction sites.

Explosion risk	A gas-air mixture between 5% and 15% concentration is explosive — a single spark ignites an explosion that destroys buildings.
No ignition	A phone call, a light switch, or a vehicle ignition near a gas leak can trigger the explosion — all ignition sources must be eliminated.
Immediate action	Gas disperses and accumulates rapidly — the first minutes after detection determine whether the situation is controlled or catastrophic.

Do

Don't

Move everyone away from the suspected gas leak immediately upon detection.
Call the National Gas Emergency Service on 0800 111 999 without delay.
Establish a cordon preventing anyone from approaching the gas escape area.
Eliminate all ignition sources — do not switch anything on or off nearby.
Ventilate enclosed spaces by opening doors and windows if safely accessible.
Do not attempt to stop the gas leak yourself — wait for gas company engineers.
Brief all excavation workers on the gas emergency number before digging near mains.
Keep the gas emergency number displayed at the site entrance and in welfare areas.
Report even small gas smells — minor leaks can escalate to major escapes rapidly.
Cooperate fully with the gas emergency response team when they arrive on site.

DON'T stay near a suspected gas leak — move away from the area immediately.
DON'T delay calling the gas emergency number — dial 0800 111 999 straight away.
DON'T allow anyone back into the cordoned area until the gas company confirms safe.
DON'T switch lights, phones, engines, or any electrical equipment near a gas leak.
DON'T enter enclosed spaces where gas may have accumulated without ventilating first.
DON'T attempt to repair a gas leak yourself — only gas company engineers are qualified.
DON'T start excavation near gas mains without everyone knowing the emergency procedure.
DON'T hide the emergency number — it must be visible to everyone on site.
DON'T dismiss small gas smells as unimportant — report every suspected leak immediately.
DON'T obstruct the gas emergency team — give them full access and cooperation.

See also: Working Near Gas Mains | Service Strike Emergency Procedure

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