Propylene glycol is a synthetic liquid substance that absorbs water. Propylene glycol is also used to make polyester compounds and as a base for deicing solutions. Propylene glycol is used by the chemical, food, and pharmaceutical industries as an antifreeze when leakage might lead to contact with food.

Volatile, colorless liquid with a sharp musty odor like rubbing alcohol. Vapors are heavier than air and mildly irritating to the eyes, nose, and throat. Sold in 70% aqueous solution as rubbing alcohol.

Methanol appears as a colorless fairly volatile liquid with a faintly sweet pungent odor like that of ethyl alcohol. Completely mixes with water. The vapors are slightly heavier than air and may travel some distance to a source of ignition and flash back. Any accumulation of vapors in confined spaces, such as buildings or sewers, may explode if ignited.

Ethanol appears as a clear colorless liquid with a characteristic vinous odor and pungent taste. Vapors are heavier than air. Ethanol with a small amount of an adulterant added to be unfit for use as a beverage.

N-butyl Alcohol occurs naturally as a result of carbohydrate fermentation in a number of alcoholic beverages, including beer, grape brandies, wine, and whisky.