Recent research shows that BPA can be an endocrine disruptor at concentrations as small as 1 part per billion! There is definite harm in BPA. For more information on this unfortunate "advance" in plastics, you can check out the books, "Slow Death By Rubber Duck" and "The Hundred Year Lie". Both are extremely informative.
The best thing you can do when feeding your baby is to breastfeed. No plastic required! While there are toxins in human milk, there are toxins in formula too. While no formula company would ever talk about it, cows are grazing on fields that are sprayed with pesticides and other chemicals, and are exposed in the environment to the same kinds of toxins that humans are. There are no "risk free" feeding alternatives given human-generated contamination of the environment in general. However, human milk gives your baby the best possible chance of reducing the harm of any contamination or toxin, as well as the best chance of the best health outcome.