Most HAPs come from human-made sources, factories, refineries and power plants, as well as building materials and cleaning solvents. Benzene, perchloroethylene, methylene chloride, dioxin, asbestos, toluene, as well as metals such as cadmium, mercury, chromium and lead compounds are some of the most common HAPs. These HAPs are used in everything from gasoline, to some dry cleaning facility processes, as well as industrial applications such as paint stripping. See a list of common pollutants and equipment.