Hydrotreating is a chemical process used in the oil refining industry to improve the quality of petroleum products. It involves treating crude oil fractions with hydrogen gas in the presence of a catalyst. This process helps remove impurities such as sulfur, nitrogen, and metals, resulting in cleaner fuels and lubricants. The main goal of hydrotreating is to produce low-sulfur fuels that meet environmental regulations. By reducing harmful emissions, hydrotreating contributes to cleaner air and helps refineries comply with standards set by organizations like the Environmental Protection Agency (EPA).