What Is Propylene Glycol or PG

According to Wikipedia http://en.wikipedia.org/wiki/Propylene_glycol and other sources, Propylene Glycol (PG) is "generally regarded as safe" by the FDA. It is used in many, many things including:

• As a solvent in many pharmaceuticals, including oral, injectable and topical formulations (notably, diazepam, which is insoluble in water, uses propylene glycol as its solvent in itsclinical, injectable form^[5])
• As a humectant food additive, labeled as E number E1520
• As an emulsification agent in Angostura and orange bitters
• As a moisturizer in medicines, cosmetics, food, toothpaste, shampoo, mouth wash, hair careand tobacco products
• As a carrier in fragrance oil
• To produce polyester compounds
• As an ingredient in massage oils
• In hand sanitizers, antibacterial lotions, and saline solutions
• In smoke machines to make artificial smoke for use in firefighters' training and theatricalproductions
• In electronic cigarettes, as a vaporizable base for diluting the nicotine liquid
• As a solvent for food colors and flavorings
• As an ingredient, along with wax and gelatin, in the production of paintballs
• As a moisture stabilizer (humectant) for snus (Swedish style snuff)
• As a cooling agent for beer and wine glycol jacketed fermentation tanks
• As a nontoxic antifreeze for winterizing drinking water systems (for example recreational vehicles), and in applications where the used antifreeze eventually will be drained into the soil, water, or a septic system
• As a less-toxic antifreeze in solar water heating systems
• As a solvent used in mixing photographic chemicals, such as film developers
• In cryonics
• As a working fluid in hydraulic presses
• As a coolant in liquid cooling systems
• To regulate humidity in a cigar humidor
• As the killing and preserving agent in pitfall traps, usually used to capture ground beetles
• As an additive to pipe tobacco to prevent dehydration
• To treat livestock ketosis
• As the main ingredient in deodorant sticks
• To deice aircraft
• As an ingredient in UV or blacklight tattoo ink
• As a lubricant in air conditioning compressors
• As a wetting agent, used to determine drying time in paints and coatings
• Used in the beverage mixer Sweet N Sour.
• Used IN antifreeze because it can act as a coolant.
• It is NOT ANTIFREEZE that is used everyday in automobiles. That product is ETHYLENE GLYCOL. For PG to be toxic a person would have to ingest gallons in a short amount of time. 
•  some electronic cigarette users who inhale propylene glycol vapor may experience dryness of the throat or shortness of breath . As an alternative, some suppliers will put Vegetable Glycerin in the "e-liquid" for those who are allergic (or have bad reactions) to propylene glycol.

All of our "E-juice" is made of 50%PG and 50%VG for optimal "throat hit" and fog.