What substances are made when a candle burns?

Burning candles mostly emit carbon dioxide and water vapor, which is a product of hydrogen and oxygen. Research has suggested that certain types of candles, such as the traditional paraffin candle, may also give off toxic chemicals such as toluene.

While candles made of soybeans still give off carbon dioxide and water vapor, they have not been known to give off more toxic chemicals like those found in burning paraffin candles. Burning candles can contribute to a small amount of indoor air pollution. The levels of volatile organic compounds produced are very low in comparison to total indoor air standards.