BHA is a preservative used in cereals, potato chips and chewing gum to stop them from becoming rancid. It has been shown to cause cancer in mice, rats and hamsters. The U.S. Department of Health and Human Services considers BHA to be a carcinogen and that it poses a reasonable risk to health. Despite this warning, the FDA still allows BHA to be used.The United States Food and Drug Administration consider both BHA and BHT to be safe. Researchers estimate the typical intake of BHA has no dangerous effects, and it would take at least 125 times the usual amount to become toxic. BHT is also considered to be safe; however large amounts of BHT may have some interactions with hormonal birth control methods or steroid hormones, and may increase levels of liver enzymes. Currently the FDA allows food manufacturers to use BHT; however additional safety studies are suggested.