An oil refinery is a facility that processes crude oil into useful products. The refining process involves separating the various components of crude oil through methods like distillation. This results in products such as gasoline, diesel, jet fuel, and other petrochemicals. Refineries also play a crucial role in ensuring that these products meet specific quality standards and environmental regulations. They often include units for treating and converting heavier fractions of oil into lighter, more valuable products. Overall, oil refineries are essential for transforming raw materials into fuels and chemicals that power modern society.