It usually contains propylene glycol, glycerin, nicotine, flavorings, additives, and contaminants. Carboxylic acids are used in the production of polymers, pharmaceuticals, solvents, and food additives. These people may benefit from a diet with a low content of preservatives and additives. The additive is equal to the product of the additives. Chevron's downstream operations manufacture and sell products such as fuels, lubricants, additives and petrochemicals. It is also a component of some food additives and food flavorings. This provided a basis for challenge with these additives and natural chemicals. This allows it to react with different compounds, such as sugars and other food additives. Levulinic acid is used as a precursor for pharmaceuticals, plasticizers, and various other additives. It has many practical applications including corrosion inhibitors, wastewater additives, and agricultural polymers. Benzene and many antiknocking additives are carcinogenic. There is very limited toxicological data on inhaling flavoring additives. The fat soluble additives are mixed into the oil. One of the most crucial additives are heat stabilizers. Isopropyl alcohol is a major ingredient in "gas dryer" fuel additives.