Candles, Chemicals, and Cancer – A Heated Subject

Deborah deMoulpied

As the cold, dark days of winter envelop the northern hemisphere, many of us find solace in the warm glow of candles. Candles have become a staple in home decor, offering a serene and inviting ambiance. However, beneath their calming presence lies a less-known, potentially hazardous reality.

The journey of candles from necessity to luxury is intriguing. Once essential for nighttime visibility, the advent of electricity relegated candles to a decorative role. In the 1980s, their popularity surged, not for illumination but for their aesthetic and aromatic qualities, leading to a boom in the candle industry. Yet, this rise in popularity brought to light some unsettling research findings.

Studies have consistently shown that candle burning releases a cocktail of toxic chemicals. These include carcinogens, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), ultrafine particles (UFPs), and soot, all of which pose significant health risks. Soot is conclusively associated with lung cancer. 

The type of candle plays a crucial role in the level of emissions. Paraffin wax candles – made from fossil fuels – are of greatest concern. That soot stuck to the inside of the Yankee Candle jar? It’s but a fraction of what actually became airborne and landed on your furniture or went deep into your lungs. 

But it’s not just the wax that’s problematic. The addition of scents and colors to candles further increases the release of harmful chemicals. Even unlit candles can emit these toxic compounds! Many people experience adverse reactions such as headaches and coughing from these additives, with some studies even linking scented candles to specific health risks such as bladder cancer.

⭐️ LEARN MORE: How To Create a Healthy, Nontoxic Home

Despite a booming market worth over $8 billion globally, the true impact of candles on indoor air quality and health remains a contentious issue. Industry-sponsored studies usually downplay the risks, focusing on compliance with regulatory standards. However, these studies have limitations, often ignoring the cumulative effect of burning multiple candles, which adds to already poor indoor air quality and could surpass safe thresholds. And the conflict of interest is obvious – like asking the manufacturer of Marlboro cigarettes whether it’s safe to smoke. 

So we are still left with the question: is it safe to burn candles?  The truth is: “Sometimes, it can be –  it depends.” If candlelight brings you a sense of well-being and comfort, there are things you can do to enjoy candles more safely. 

The most important best practice is to burn 100% beeswax, 100% soy, or 100% coconut wax candles without artificial fragrance. (Pure essential oils are better, but will still emit some VOCs).  Beeswax, with its higher melting point, burns  “hotter” than other waxes, thereby having almost complete combustion with less emissions.  

No matter which type of candle you use, these guidelines are recommended: 

1 – Burn fewer candles at once. 

2 – Burn candles for special occasions and not on a regular basis.

3 – Keep the wick short, 1/8 to a ¼ inch. A longer wick draws up more wax and does not fully combust, resulting in more soot.

4 – Avoid drafts that make the flame flicker.

5- Ventilate, if possible, without creating a draft.

6 – Light quickly and snuff out the flame quickly, avoiding smoke.

7 – Avoid deep glass jars, as not enough oxygen gets to the flame. This results in less combustion/more soot.

8 – Avoid burning candles for an extended period of time.

9 – Use battery powered faux candles.

10 – Instead of scented candles, use a diffuser with real essential oils for ambiance. Or make your own diffuser by simmering some cinnamon sticks and orange peels!

Candlelight can have a powerfully positive effect on mood. It can comfort, soothe, and calm even frayed nerves. At the table, the soft glow of candlelight can make even the simplest meal feel romantic and special. 

In my home, I think of candles as I think of chocolate cake: great to enjoy on occasion, but best not to make a habit of it. 100% soy, beeswax, and coconut candles also make nice gifts for any occasion – and who knows? They might spark an enlightening conversation about candles that brings a breath of fresh air to your friends and family. 


Fine Particulate Matter Emissions from Candles

Occupational Exposure to Ultrafine Particles and Polycyclic Aromatic Hydrocarbons from Candle Emissions

Candles and Incense as Potential Sources of Indoor Air Pollution 

Deciphering the Code between Air Pollution and Disease: The Effect of Particulate Matter on Cancer Hallmarks – PMC 

Soot – Cancer-Causing Substances – NCI 

Evaluation of Combustion Gases in Scented Paraffin Candles

Evaluating Emissions in Combustion Gases of Candles

(PDF) Combustion characteristics of candles made from hydrogenated soybean oil.

US Scented Candles Study

Emissions of soot, PAHs, ultrafine particles, NOx, and other health relevant compounds from stressed burning of candles in indoor air – Andersen

Incense smoke: clinical, structural and molecular effects on airway disease – PMC

Polycyclic Aromatic Hydrocarbons (PAHs): What Health Effects Are Associated With PAH Exposure? | Environmental Medicine | ATSDR

The Impact of Candle Burning During All Saints’ Day Ceremonies on Ambient Alkyl-Substituted Benzene Concentrations

Exposure to polycyclic aromatic hydrocarbons with special focus on cancer – ScienceDirect

Some Candles Emit Hazardous Materials for Human Health and are Indoor Air Pollutants 

Characterization of hazardous and odorous volatiles emitted from scented candles before lighting and when lit 

Evaluation of Gaseous and Particulate Emissions from Scented and Unscented Candles

Extent of exposure to scented candles and prevalence of respiratory and non-respiratory symptoms amongst young university students | BMC Public Health.

Scented Candles as an Unrecognized Factor that Increases the Risk of Bladder Cancer; Is There Enough Evidence to Raise a Red Flag? 

Beyond Aromatherapy: Illuminating the Underappreciated Risks Associated with Scented Candle Exposure | Environmental Science & Technology

Human health risk evaluation of selected VOC, SVOC and particulate emissions from scented candles – ScienceDirect

Particulate Matter Indoors | American Lung Association 

⭐️ LEARN MORE: How To Create a Healthy, Nontoxic Home

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