Pallets are made from trees. Pallet recycling is a win-win: it reduces landfill waste (less pressure on forests) and provides another chance for products to be used. Wooden pallets are not painted. Since 2007, cargo containers have been required to be made from new materials so there is no excuse for pallets being made of anything but 100 recycled plastic.
To meet this requirement, a synthetic product called thermoset plastic is used which cannot biodegrade and will remain on our planet forever. The good news about these pallets is that they can be recycled into other products.