Here is the study theyre referring to: https://www.sciencedirect.com/science/article/abs/pii/S0278691522003350

Background information and context: The proposal is based on the study (in rats) where toxicity was observed when rats fed on food that contained 0.1 (male) and 0.5% (female) w/w brominated vegetable oil. Rats typically eat about 5% of their weight in food daily which means that the equivalent BVO dose for a 70kg man would be ~3.5 grams/day. Sodas that contain BVO are required to have less than 15 ppm BVO. In order to consume 3.5 grams of BVO via soda, you would need to drink over 230 liters (approx. 60 gallons). AFAIK there is one recorded case of brominism (bromine toxicity) from drinking gallon+ quantities of BVO containing soda daily long term.