Scented candles are often used to help relax or find calm after a long stressful day.   Unfortunately, your candle isn’t just adding a comforting fragrance to your home, they could also be releasing toxic fumes and chemicals.

When burned, regular candles release carbon monoxide, soot, and various chemical compound into the air.  These chemicals include toluene and benzene.

Toluene is usually associated with fumes emitted from paint thinners.  It can irritate your eyes, nose, throat, and skin.  It can hinder breathing and worsen the effects of asthma or other respiratory illnesses.  It can also lead to tiredness, confusion, headaches, dizziness, anxiety, and insomnia.  There is also evidence it can damage kidneys, liver, and nerves.

Benzene is one of the toxins released from smoking cigarettes.  It is an industrial chemical that has carcinogenic associations.   In other words, it’s linked to cancer.  It should be noted that the amount of benzene emitted by candles is significantly lower than cigarettes, however, if you burn a lot of candles, it will add up.

The health implications of burning candles can vary from person to person.  People with any kind of lung disease or sensitivity such as asthma should be more cautious. And families with children should be even more careful.

What about scents candles?  Scented candles are likely to contain volatile organic compounds (VOC) such as formaldehyde.  Exposure to this can result in allergic reactions and worsen existing respiratory problems.  Recent studies have also shown that exposure to scented candles can result in headaches, shortness of breath, and coughing.  Longer exposures could lead to sneezing and wheezing.

What’s best?

The safest option is fragrance-free candles.  If you want candles with a pleasant smell go for a candle with natural wax and ingredients or essential oils.  Paraffin candles are made of a petroleum compound and can increase the release of formaldehyde when compared to beeswax or plant based waxes.  As well, avoid coloured or metallic wicks which could contain toxic chemicals.  Undyed cotton, paper, or wooden wicks are a safer option.

Tips to burning candles:

Use them in a well-ventilated room:  

Open the doors or windows for cross-ventilation.  If you use a candle in the bathroom, turn on the overhead fan.

Keep candles away from anything flammable:  

Place them at least one foot away from any object that could burn.

Wick length:

Keep the wick trimmed to a quarter of an inch.

Blowing out candles:

Don’t blow out candles as this produces more stock and fumes. Instead use a snuffer.

Smoky Candles:

Get rid of smoky candles.  if you notice a candle is smoking, toss it out. The smoke indicates toxins and particulate matter is being released into the air.

https://www.livestrong.com/article/13776566-are-candles-bad-for-you/