CHICAGO — When Gatorade fan Sarah Kavanagh learned that her favorite drink contains an emulsifier banned in other countries over health concerns, she was taken aback.

‘I was shocked that they’d put their consumers at risk like that and that the FDA would allow something like that to be put in products,’ said the Mississippi 15-year-old, who launched a petition in November asking Gatorade to remove the ingredient, called brominated vegetable oil, or BVO.

The petition, which has attracted more than 200,000 supporters on Change.org, notes that the ingredient shares an element — bromine — with some flame retardants used in furniture and plastics. Some studies on BVO indicate it can build up in fatty tissues and cause reproductive and behavioral problems in rodents.

It’s illegal to use the chemical as a food additive in the European Union India, Nepal, Canada, Brazil and Japan. Other ingredients that are allowed in American food but not in other countries include certain artificial colors and additives that improve flour.

Why the difference? The U.S. Food and Drug Administration would not provide a representative for an interview, but in past statements to the media and on its website the agency has presented a variety of reasons for allowing […]