The KeepCup and all its components are BPA and BPS free! The cup itself and the lid are made from polypropylene, the plug is a LDPE, the booster is made from a tritan a copolymer polyester, the thermal band is made from silicone.
We researched our plastics with care. Polypropylene #5 is the safe food grade plastic.
Bisphenol A (BPA) is contained in polycarbonate (plastic #7). The other plastic to avoid as reusable is #2 PET.
The numbers relate to the chemical compounds used to manufacture the plastic and must be displayed. #7 is a catch all for all unclassified plastics.