Yesterday, Monday, an explosion occurred at the Valero oil refinery in Port Arthur, Texas. Port Arthur Emergency Management officials issued a warning, calling on residents in nearby areas to remain in their homes, "for the safety of everyone in the wake of the explosion." The refinery, affiliated with Valero Energy, employs about 800 people and specializes in processing heavy sour crude oil and other raw materials, and converting them into products such as gasoline, diesel and jet fuel, according to the company’s website.