Scented candles may be hazardous to your health.
The ingredient limonene, which is used to give candles their citrus scent, mutates into the chemical formaldehyde when it makes contact with the air, research performed by professor Alastair Lewis of the National Center for Atmospheric Science at the University of York found, The Telegraph reported.
Limonene is also found in cleaning products and air fresheners that have a lemony scent. On its own, it is considered safe enough to even flavor food, but when it is released into the air and reacts with naturally occurring ozone, every two limonene molecules mutate into formaldehyde.
Exposure to formaldehyde may cause symptoms like watery eyes, burning sensations in the eyes, nose and throat, coughing, wheezing, nausea and skin irritation.
Before Lewis began his scented candle test, it was well known that limonene can degrade into formaldehyde.
But he found the concentrations of limonene in scented candles are up to 100 times higher than previously thought. Given the small amount of energy and air that escape homes, the high concentrations of formaldehyde from scented candles may cause long-term harm to individuals.
“The really surprising thing is just how high the concentrations of some fragrances are now in people’s homes…Fragrance chemicals now completely dominate the inside of most homes,” Lewis said.
“The issue is we don’t really know what the consequences of long-term exposure to formaldehyde are. It is a chemical that is known to harm you long-term,” he added.
Since 1987, formaldehyde has been classified by the EPA as a probable human carcinogen, meaning it may cause cancer, according to the National Cancer Institute. The International Agency for Research of Cancer and the National Toxicology Program both classify the chemical as a known human carcinogen.
Formaldehyde exposure may cause cancers of the hematopoietic and lymphatic systems, particularly myeloid leukemia.
The National Candle Association issued a response to news reports, which were provoked by Lewis’ research, about the alleged danger associated with using a scented candle:
The National Candle Association assures consumers that candles, whether scented or unscented, when used properly, are safe...
...Consumers can be confident that a well-made and properly burned candle, whether scented or unscented, will burn cleanly and safely,” the statement said. “Although there are no known health hazards associated with the use of scented candles, unfounded concerns about the safety of man-made fragrances vs. “natural” fragrance materials and essential oils continue to pepper popular media and Internet. The fragrances approved for candle usage – whether synthesized or “natural” – do not release toxic chemicals.