Plastics have become common in our everyday lives. Most are made from petrochemicals (non-renewable resources), many are not readily recyclable, and they are often used to make single-use, disposable items that end up in landfill. Chemicals are typically added to plastics to give them certain qualities, such as to make them soft or hard, or to give them colour or fire resistance. Some of these chemicals are thought to be harmful to human health and the environment. Polyvinyl chloride (PVC, or vinyl), polystyrene and polycarbonate are three plastics that contain chemicals of concern and should be avoided, when possible.