REGULATION: Death of a Dye

Without it, instant chocolate pudding would be greenish, artificially flavored grape soda would look blue, and cake mixes would have a lemony-green tinge. The substance is Red Dye No. 2, which has been used for decades to brighten up innumerable products, including frankfurter casings, pet foods, ice cream, gravies, makeup and myriad red pills. About 1 million pounds of the coal-tar-based stuff—a $5 million industry in itself—have ended up annually in more than $10 billion worth of foods, drugs and cosmetics.

Now all that is ending. Last week the Food and Drug Administration...