Made from the material, Mater-Bi, all of these bags contain GMO free starch, biodegradable polymer and other renewable resources. No polyethylene is used in the production process. These bags meet ASTM D6400 specifications and California SB 1749 requirements. The BioBag "breathes", and reduces the weight of its contents by up to 25% in five days depending on the water weight. Note: not available for nedt day delivery--may take up to 3 business days to arrive.