Lining the shelves of American supermarkets are food products with chemicals linked to health concerns. To a great extent, the FDA allows food companies to determine for themselves whether their ingredients and additives are safe.

Companies don’t have to tell the FDA about those decisions, and they don’t have to list all ingredients on their product labels. Instead, companies can use broad terms such as “artificial flavors.”

In 1958, Congress mandated that before additives could be used in foods manufacturers had to prove they were safe and get FDA approval. However, Congress carved out an exception for substances “generally recognized as safe,” which came to be known simply as GRAS.

As conceived, GRAS promised regulatory relief for standard ingredients like salt, sugar, vinegar, and baking powder. Over time, “the loophole swallowed the law,” said a 2014 Natural Resources Defense Council report.

Health and Human Services Secretary Robert F. Kennedy Jr. wants to close or tighten the GRAS loophole. He has railed about the risks of food additives for years and has said he wants to end “the mass poisoning of American children.”

Whether changes come from the FDA or the food companies, it’s clear Americans are becoming more concerned about what they’re buying.