Your Favorite Scented Candle Might Be as Toxic as Car Exhaust.

Scented candles—especially paraffin-based—don’t just smell cozy. Multiple studies show they release toxic chemicals like benzene, formaldehyde, toluene, carbon monoxide, and polycyclic aromatic hydrocarbons (PAHs)—many of which are carcinogenic, hormone-disrupting, or linked to respiratory disease.

A 2025 study in Nature found that poor combustion can spike indoor PM₂.₅ and PAHs up to 20× above outdoor levels. Earlier research (Orecchio 2011, Petry 2014, Steinemann 2015) revealed hidden VOCs and soot that may cause bladder cancer, asthma, or even lipoid pneumonia from inhaling paraffin vapors. A 2023 BMC Public Health survey showed 1 in 4 scented candle users reported headaches, wheezing, or sneezing after just 60 minutes of use.

If you love a cozy atmosphere, opt for beeswax or unscented soy candles with cotton wicks—and crack a window. Your lungs will thank you.