Candles make your home smell good, but according to an Arizona physician, they’re not all that great for your health.

“We’ve always known candles have had the risk of burning down houses and structures but now there is another risk, a health risk, known as lung inhalation injury,” Radiation Oncologist Dr. Vershalee Shukla with Vincere Cancer Center in Scottsdale said.

It stems from the cheap oil and fragrances that do not allow for efficient burning, which causes incomplete combustion. That produces black soot that poses great threats to our health.

The soot can be seen not only around the top of the candle but on your walls, furniture, and lungs.

“When we actually tested the emission from burning candles, over 20 volatile organic compounds were identified including lead and significant amounts of carbon were also identified,” Shukla said. “These particles can deposit deep in your lungs causing inflammation, scar tissue and breathing problems in the future.”

But who is at the greatest risk for lung inhalation injury? Shukla says it is people who already suffer from heart and/or lung disease, due to the fact that their lungs are already not functioning properly.

So, what’s the best way to not breath in soot full of chemicals? That’s an easy one, don’t burn candles.

But if you do, make sure they are high quality and trim their wicks.

The National Candle Association continues to identify candles that pose a risk and have ongoing research to learn about some candles’ risk.