Many chemicals test as carcinogenic when administered in extremely high doses over a prolonged period of time to laboratory animals. The doses given are often just below lethal doses. These studies do not equate to actual human exposure.
There are plenty of reasons to avoid soda (I hate the stuff), but being afraid of trace quantities of the caramel coloring isn’t one of them.
It reminds me of a scare in the early 70s about a synthetic sweetener. It turned out that the amount given the rats was equivalent of a human drinking several cases a day.