Modern and well-maintained central heating boilers are more likely to cause carbon monoxide poisoning than old boilers, the Dutch safety board said on Wednesday.

In accidents involving carbon monoxide, 46% are caused by heating systems, most of which are new or are maintained by a professional, the board said.

There are also more victims than thought. Current thinking is that there are five to ten deaths per year through carbon monoxide poisoning and hundreds of people needing treatment.

However, the safety board said this is an underestimate because the symptoms of carbon monoxide poisoning often go unrecognised.

The safety board is highly critical of heating system engineers who, they said, pay too little attention to ventilation and smoke extraction in buildings

They want manufacturers to make heating systems safer. For instance, systems do not automatically switch off if they are making too much carbon monoxide. Nor do they switch off if they are wrongly installed. ‘They are not foolproof,’ the safety board said.

‘The government must take responsibility for a system which guarantees the safety of the public,’ the safety board said.