What is the American Petroleum Institute known as API? The API is about the oil and natural gas industry as a trade organization with world re-known publications to make the oil and natural gas industry safer. The American Petroleum Institute started at the onset of World War One to solidify the industry to the benefit of the country. An example of API Standard was the API 650 that is a worldwide standard to design safe aboveground storage tanks with reasonable economy for use in the storage of petroleum, petroleum products, and other liquid products. API developed this standard to help purchasers and manufacturers order, fabricate, and erect tanks properly.