Oil refineries can be found throughout the U.S. These factories process heavy crude oil into a variety of petroleum products including gasoline, heating oil, diesel fuel and kerosene. Asbestos was used to insulate many pipes, pipelines, and equipment that operated at high temperatures. Some refinery workers also wore protective clothing such as pants, aprons, gloves, and shoe covers that were made with asbestos fibers. In some cases, asbestos was also present in the plant itself – such as in the floors and ceiling tiles of the various buildings.