Once cyclamates were banned, American producers turned to saccharin. Saccharin alone was often criticized for having a bitter taste and "chemical" aftertaste. Some manufacturers, such as Coca-Cola with Tab, attempted to rectify this by adding a small amount of sugar. In 1977, the FDA was petitioned to ban saccharin, too, as a carcinogen, but a moratorium was placed on the ban until studies were conducted. The ban was lifted in 1991, but by that time, virtually all diet soda production had shifted to using aspartame. Perhaps the most notable holdout is Tab, which nevertheless also uses some aspartame in its formula.