Formaldehyde – What is it in Vaping?
Definition
Formaldehyde is a colourless, pungent gas (CH₂O) that can form when Nicotine“>freebase nicotine e-liquids or sweet flavour additives are overheated in a vape device. It is not intentionally added; instead, it appears as an unwanted thermal breakdown product when cotton wicks run dry or coils reach extremely high temperatures. In vaping, formaldehyde is a safety concern rather than a functional ingredient, as it can irritate the lungs and is classified as a probable carcinogen.
Technical Details
How It Forms
Formaldehyde is generated when glycerol (VG) and propylene glycol (PG) are heated above ≈250 °C on a dry or gunked coil. The reaction accelerates on Fused Clapton or other high-mass coils that retain heat longer. Laboratory tests have measured up to 150 µg per 15 puffs under “dry-puff” conditions—far above workplace safety limits. Variations include hemi-formals, which are short-lived polymers that can also irritate airways.
Detection
- Distinctive sharp, chemical aftertaste
- Harsh Hit“>throat hit even with low-nicotine liquids
- Visible black carbon spots on wick or coil
Usage & Tips
Minimising Exposure
- Prime coils properly to avoid dry hits; flooding is safer than burning.
- Keep wattage within coil rating; high-mass builds need lower temperatures.
- Replace wicks when flavour fades or after 20–30 mL of sweet e-liquid.
- Refill promptly; never vape when the Port“>fill port level is below the wick ports.
If you taste a “dry, plasticky” note, stop vaping, re-wick, and check for charred cotton.
History / Context
Formaldehyde fears surfaced in 2015 after a New England Journal of Medicine study reported high levels under unrealistic “dry-puff” conditions. Subsequent Australian research confirmed that normal, saturated vaping produces negligible formaldehyde, shifting focus to user technique rather than product bans.