Rongalite, also called Rongalit (registered trademark of BASF), is sodium hydroxymethylsulfinate, or NaHOCH₂SO₂. The salt has many names, including also sodium formaldehyde sulfoxylate, and Bruggolite. It is listed in the European Cosmetics Directive as sodium oxymethylene sulfoxylate (INCI). It is water-soluble and generally sold as the dihydrate. The compound and its derivatives are widely used in the dye industry.