Firefighters used specialist equipment to carry out a sweep of the flat and communal areas on arrival and confirmed that no elevated readings of carbon monoxide were identified. A man, a woman and two children were taken to the hospital as a precaution. 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 12.09pm and the incident was over for firefighters by 2.16pm One fire engine from Hendon Fire Station and a fire rescue unit from Wembley Fire station attended the scene. CO poisoning symptoms: Headaches Dizziness Nausea or vomiting Breathlessness Collapse Loss of consciousness These symptoms also apply to your pets – so keep an eye on them too. Poisoning symptoms can easily be confused with just feeling unwell, which is why CO poisoning is so dangerous, and so often missed.