Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Made of unsafe polycarbonate plastic

These cups are made of polycarbonate plastic, which is a known toxic plastic, especially unsafe in food/drink storage. Nuby makes other two handled sippy cups that are made of safe polypropylene plastic. Cups made of unsafe PC plastic are usually clear and hard, while cups made of safe PP plastic are softer and "clouded" plastic.