Benzene in soft drinks 

To summarize: avoid sodas with potassium benzoate and vitamin C (most fruit-flavored sodas), as they combine over time into benzene (an industrial solvent). If you can't bear to be without them, pay attention to the dates on the packaging: get it new, store it in a cool place out of the sun, and don't keep it for long. You should probably avoid buying such sodas in restaurants or other places where you are unsure of how they store their drinks, unless you relish drinking solvents (think WD-40).