According to EWG, in 1990, the FDA learned that certain soft drinks marketed to children contain two ingredients that can mix in the soda to form the toxic carcinogen benzene. The Agency didn't tell the public, but instead merely asked companies to voluntarily change their formulas to eliminate the problem.
So far in 2006, two news outlets have reported that the Agency is again testing soft drinks, finding benzene sometimes at levels above the safe limit for drinking water, and asking companies to change their formulas.
On February 24 and February 27, 2006, EWG staff found many juices and sodas at major national retail outlets containing the ingredients that can form benzene.
:: Via EWG