There is no real distinction between "natural" and synthetic or conventional paints. So called "natural" paints may contain VOCs, e.g. ethanol and turpentine. Turpentine, although a natural product, is still a VOC and carries its own hazards and is classified as harmful. On the other hand, conventional paints may contain up to 70% of renewable plant material, e.g. soyabean oil, linseed oil.