London Fire Brigade were called to a suspected carbon monoxide leak at a house on Bedford Avenue in Hayes.
Firefighters used specialist equipment to confirm elevated readings of carbon monoxide on arrival. Two adults and two children were taken to hospital by London Ambulance Service crews.
The gas supply was isolated, and crews ventilated the property and carried out a sweep of the building to confirm that no further elevated readings were found.
A London Fire Brigade spokesperson said: “You can’t taste, see or smell CO fumes, but it can kill in minutes.
“It’s really important to fit a CO alarm in all rooms containing fuel burning appliances, ensuring that the alarm is able to be heard throughout your home. When sleeping, it is important that your alarm would wake you if it sounds.
“It’s also a good idea to familiarise yourself with the signs of carbon monoxide poisoning and learn what to do if you suspect someone may be affected.”
The Brigade was called at 9:54am and the incident was over for firefighters by 11:10am. Two fire engines from Southall Fire Station attended the scene.
Source: London Fire Brigade