The seventh synthetic flavor, styrene, was removed because manufacturers no longer use it.

The FDA decision is "an important victory for consumer confidence," Laura MacCleery, policy director for the Center for Science in the Public Interest, said in a statement. MacCleery added that the FDA action was a response to a 2016 petition and a subsequent lawsuit asking for an FDA response.

The six substances are synthetically derived anibenzophenone (benzophenone), ethyl acrylate, eugenyl methyl ether (methyl eugenol), myrcene, pulegone and pyridine. Benzophenone can no longer be used in rubber articles that come into contact with food, the FDA said.

Companies who use these six additives will have 24 months to identify suitable replacements in food products, the FDA said. 

The additives, said MacCleery, were deemed safe by the FDA in 1964 and have been commonly used in candy, ice cream, chewing gum, baked goods, drinks and other foods since that time. The US Department of Health and Human Services' National Toxicology Program tested the additives and found they caused cancer in two species of animals, according to the petition.