Don't go overboard on the candles, researchers warn. The fumes of paraffin wax candles can contribute to cancer and asthma, though it would take years of heavy use to cause a problem, the BBC reports. “An occasional paraffin candle and its emissions will not likely affect you,” says one scientist involved with the new study.
“But lighting many paraffin candles every day for years or lighting them frequently in an un-ventilated bathroom around a tub, for example, may cause problems.” The trouble, scientists found, is that candles don’t give off enough heat to combust unhealthy chemicals. Beeswax or soy-made candles might be a better choice.