Smarter: Are Candles Bad for Your Health?

So are candles harmful to your health? 
The short answer is mostly no, says Brian W. Christman, MD, a professor in allergy, pulmonary, and critical care medicine at Vanderbilt University Medical Center in Nashville and spokesperson for the American Lung Association.

A 2014 study found that under normal conditions, using scented candles doesn’t pose known health risks to people. While small amounts of potentially harmful chemicals, such as formaldehyde and toluene, were detected, those levels were well below the standards of safe exposure determined by the World Health Organization, Brian says, citing the study.

It should be noted that the study’s funding has ties to the fragrance industry, though Brian says the study seems to have been well controlled and its findings straightforward.

That’s not to say that candles are entirely risk-free. Long-term studies on the health effects of candle use are limited, says Amanda Dilger, MD, an ear, nose, and throat doctor at Mass Eye and Ear at Mass General Brigham, a Boston-based nonprofit hospital and physician network.

Candles can worsen indoor air quality with the release of pollutants, including black carbon, formaldehyde, particulate matter, polycyclic aromatic hydrocarbons (PAHs), and nitrous oxide. Children and people with heart and lung conditions might want to be more careful with candles because they’re at higher risk of being affected by indoor air pollution, Amanda says.

Does the choice of candle make a difference? In other words, are some candles safer than others?
Paraffin-based candles have been found to release a number of toxins, including benzene and toluene, while research has shown that soy wax candles burn slower and produce less soot, Amanda says. However, it’s worth noting that more studies are needed to better understand the potential health effects of different types of candles.

For the time being, you’re probably better off avoiding paraffin candles just from an environmental perspective, because they’re made from petroleum, Amanda says. Instead, consider opting for candles made from materials that are more biodegradable and less fossil-fuel-based, such as soy, coconut, and beeswax, Brian says. 

Scented candles contain fragrances that release volatile organic compounds (VOCs) during combustion. VOCs have been associated with allergies and asthma, so if you’re prone to those conditions or have symptoms such as eye irritation or sneezing during candle use, it may be best to forego the scented ones, Amanda says.

What’s the best or safest way to burn candles?
Make sure your space is well ventilated, and avoid drafty areas, Amanda says. 

Also, trim wicks to a quarter-inch and remove debris from the wax pool to minimize soot released into the air.

When you’re purchasing candles, you should also find ones that are stable and won’t tip over easily, Brian says. On average, 20 home candle fires are reported each day, according to the National Fire Protection Association, so it’s good to be safe.

And to state the totally obvious, always, always blow out your candles before you go to sleep or leave your home.

Bonus link: Are gas stoves a health risk?