Vaping is the act of inhaling aerosol produced by an electronic device, which heats a liquid mixture called e-liquid or vape juice. A persistent rumor claims this liquid contains a highly toxic ingredient found in automotive antifreeze. Legitimate, regulated e-liquids do not contain the poisonous substance commonly used in standard car antifreeze.
The Chemical Confusion: Ethylene Glycol vs. Propylene Glycol
The antifreeze rumor stems from confusion between two chemically distinct compounds: ethylene glycol and propylene glycol. Ethylene glycol is used in traditional automotive antifreeze and is highly toxic if ingested, potentially leading to severe illness or death.
Propylene glycol (PG) is the primary ingredient in most e-liquids and has a very low toxicity profile. PG is classified as “Generally Recognized as Safe” (GRAS) for use in foods, cosmetics, and pharmaceuticals. Although PG is used in some specialized, non-toxic antifreezes, its chemical structure is different from its toxic counterpart.
Both compounds are glycols, organic chemicals belonging to the alcohol family. They differ by only one methyl group in their molecular structure, resulting in vastly different safety profiles. PG was developed to replace ethylene glycol in applications where there is a risk of human exposure.
The Actual Components of E-Liquids
E-liquid is primarily composed of four main components: propylene glycol (PG), vegetable glycerin (VG), flavorings, and nicotine (if present). The base, 80% to 90% of the volume, consists of PG and VG. These substances are humectants, meaning they attract and retain moisture, and they create the visible aerosol when heated.
Propylene glycol functions as an effective carrier, dissolving and delivering the nicotine and flavorings. Liquids with a higher PG content typically produce a noticeable sensation in the throat, referred to as a “throat hit.” Vegetable glycerin, derived from plant oils, is a thick, clear fluid that produces dense vapor clouds.
Flavorings are food-grade chemicals, making up 3% to 15% of the mixture, dissolved in the PG base to provide various tastes. Nicotine, the final component, is included in varying concentrations or sometimes absent entirely, and is extracted from tobacco leaves.
Documented Health Effects of Vaping Ingredients
While the toxic antifreeze rumor is false, inhaling e-liquid components does have documented health effects. Short-term side effects include dry mouth, sore throat, and irritation in the nose or eyes. These minor irritations are linked to the hygroscopic nature of PG and VG, which draws moisture from surrounding tissues.
Long-term concerns focus on the respiratory system and chemical changes that occur when the liquid is heated. Research shows that repeatedly inhaling aerosolized PG and VG can lead to lung inflammation. When PG and VG are heated to high temperatures, they can break down into harmful compounds, including carcinogens like formaldehyde and acetaldehyde.
Flavoring chemicals also pose a risk, particularly compounds like diacetyl, which has been linked to the debilitating respiratory disease bronchiolitis obliterans, often called “popcorn lung.” Although diacetyl is safe to ingest in food, its inhalation causes damage to the smallest airways in the lungs. The relative newness of vaping means that the full spectrum of long-term health consequences remains uncertain and is an ongoing area of study.