Some 1.6 million people, mainly small children, die each year from a “kitchen killer” - disease brought on by inhaling smoke from cooking stoves and indoor fires, the World Health Organisation said on Friday.

“While the millions of deaths from well-known communicable diseases often make headlines, indoor air pollution remains a silent and unreported killer,” the United Nations’ agency said.

Nearly half of the world cooks using fuels like dung, wood, agricultural residues and coal, which give off a poisonous gas that “more than doubles the risk of respiratory illness such as bronchitis and pneumonia,” it said in a joint statement with the U.N. Development Programme.

Women and children living in poor rural areas of developing countries, who cook with a typical wood-fired stove, would be subject to levels of carbon monoxide and other noxious fumes that are at 7 to 500 times internationally accepted levels.

“The amount of smoke from these fires is the equivalent of consuming two packs of cigarettes a day,” WHO said, adding one life is lost every 20 seconds to the “killer in the kitchen.”

Children younger than five years old are particularly at risk of pneumonia, with some 900,000 deaths reported each year linked to smoke inhalation. Bronchitis is the main killer of women.

Although long term the solution is to replace solid fuels, there are cheap and quick steps that developing countries and rural communities can take in the meantime, said Eva Rehfuess, WHO technical officer for indoor air pollution.

Keeping children away from smoky areas and using dried wood along with lids on pans to reduce cooking time are simple actions that will reduce the toll, she said.