Gas stoves kill 40,000 Europeans every year by pumping pollutants into their lungs, according to a report. The death toll is twice as high as in car accidents.

The stoves emit harmful gases that can lead to heart and lung disease. But experts warn that public awareness of their dangers is low. Using a gas stove shortens a person’s life expectancy by almost two years on average, according to a study of households in the EU and UK.

“The scale of the problem is far worse than we thought,” said lead author Juana María Delgado-Saborit, who heads the Environmental Health Research Laboratory at the University of Jaume I in Spain.

Researchers attributed 36,031 early deaths to gas stoves in the EU each year, with a further 3,928 in the UK. They say their estimates are conservative because they only consider the health effects of nitrogen dioxide (NO).₂) and not other gases such as carbon monoxide and benzene.

“Back in 1978 we learned for the first time that NO₂ Pollution is many times higher in kitchens that use gas than with electric stoves,” said Delgado-Saborit. “But only now can we quantify how many lives are being cut short.”

One in three households in the EU cook with gas, with 54% in the UK and more than 60% in Italy, the Netherlands, Romania and Hungary. The stoves burn fossil gas and emit pollutants that inflame the respiratory tract.

The report, supported by the European Climate Foundation, builds on a study last year that measured air quality in homes to find out how much cooking with gas increases indoor air pollution. This allowed scientists from the University of Jaume I and the University of Valencia to determine the relationship between indoor and outdoor air pollution when cooking with gas and to map NO exposure indoors₂.

They then applied disease risk rates derived from outdoor NO studies₂ Pollution to determine the number of lives lost.

“The biggest uncertainty is whether there is a risk of death from exposure to NO outdoors₂ of mainly traffic can be applied to indoor spaces NO₂ from gas cooking,” said Steffen Loft, an air pollution expert at the University of Copenhagen who was not involved in the research. “But it is a reasonable assumption and necessary for the assessment.”

The findings are consistent with a US study conducted in May that found gas and propane stoves cause up to 19,000 adult deaths each year.

The EU tightened its rules on outdoor air quality this month but did not set standards for indoor air quality. The European Public Health Alliance (EPHA) has called on policymakers to phase out gas stoves by setting limits on emissions, offering money to switch to cleaner stoves and forcing manufacturers to label stoves with their pollution risks.

“For too long it has been easy to dismiss the dangers of gas stoves,” said EPHA’s Sara Bertucci. “Like cigarettes, people didn’t think much about the health effects – and like cigarettes, gas stoves are a small fire that fills our homes with pollution.”

People can partially protect themselves from fumes when cooking by opening the windows and turning on the extractor hood while cooking.

Delgado-Saborit said she and her husband grew up in homes that cooked on electric stoves, which was “cleaner, safer and healthier,” but later moved to a home with a gas stove in the kitchen.

“We are currently in the middle of some renovations to the house and I am counting down the days until a new electric hob is installed in my kitchen.”