In most cases, soybean oil is the primary ingredient in newspaper ink. A variety of chemicals are employed in the production of newspaper ink, with soybean oil being the most important. This is known as the "vehicle" in the ink and was originally created mostly using petroleum oil, while it is now primarily made with soybean oil. The printing process requires large amounts of oil, so much that over 50% of the volume of a newspaper is made up of oil. Soybean oil is the main component in newspaper ink because it is inexpensive and there is enough demand for it into which to export other products. In addition to being an economical alternative to traditional fossil fuels, soybean oil is also renewable and biodegradable. It is estimated that this amount of oil would take about five years to degrade if left untreated in the environment. However, since this oil is mixed with wood pulp when printed, it will eventually decompose into carbon dioxide and water if exposed to sunlight or other forms of air pollution. The quality of paper produced with soybean oil depends on how the oil is processed after extraction from the bean. If not done properly, the oil can contain levels of unsaturated fatty acids too high for making good ink. However, soybean oil is suitable for making printing ink because it does not go rancid like other oils do at higher temperatures. In fact, the melting point of soybean oil is around 76 degrees Fahrenheit, which makes it ideal for use in hot-press machines during printing processes.