World Centric compostable clear salad bowls are made from NatureWorks Ingeo, which is derived from plants grown in the USA. Our bowls meet the most stringent scientific requirements for biodegradability and compostability, and are ASTM D6400-99 certified for "compostable plastics". Even though they are as light and strong as plastic, they fully biodegrade when composted. Instead of using petroleum based plastics which create toxicity and environmental pollution, you can now use our compostable alternatives. World Centric bowls are certified compostable by the Biodegradable Products Institute and meet ASTM standards for compostability. Our Ingeo products are guaranteed to break down in 2-3 months in industrial facilities. Please check locally, as the facilities are not available in all communities.