While artificial preservatives such as ethoxyquin, butylated hydroxy-anisole (BHA) and butylated hydroxy-toluene (BHT) have pretty frightening names, they are classified as GRAS (generally recognized as safe) by the Food and Drug Administration (FDA). The GRAS classification indicates that there is no evidence these substances, when used at allowable concentrations in food products, result in any harmful effects. The concentrations of these substances in cat foods are very small. The allowable concentration in the fat sources is only 100 to 200 parts per million, and since the fat source is only a small fraction of a cat food, the concentration of the fat preservative in the cat food as a whole would be only 10 to 20 parts per million.