The Plastic Cover helps to protect the wooden tray surface. The Tray Cover is BPA-Free and Phlalate Free. It is made of plastic that meets or exceeds all CPSC requirements. Dishwasher safe, it is easy to clean. Plastic Tray cover is made from Polypropylene. The Recycling symbol on the tray is #5. Polypropylene is food grade plastic and is found on countless food containers. It’s a safe plastic, and is also dishwasher safe!