This is straight from the DEA's ass er mouth.
Hypophosphorus acid (H3PO2) and its salts are list I chemicals. Hypophosphorus acid is most commonly sold in aqueous solutions, all of which are regulated as list I chemicals and not regarded as chemical mixtures. There are no retail uses for this chemical. Hypophosphorus acid is commonly used by large industry as a bleaching, color stabilization or decoloring agent for plastics, synthetic fibers (primarily polyester) and chemicals. Hypophosphorus acid is also used as a chemical intermediate in organic synthesis and as a polymerization and polycondensation catalyst. It also has applications as a reducing agent and as an antioxidant.
Salts of hypophosphorus acid are known as hypophosphite salts. Examples of these salts include: ammonium hypophosphite, iron hypophosphite, potassium hypophosphite, manganese hypophosphite, and sodium hypophosphite. The two most common salts of hypophosphorus acid are sodium hypophosphite and manganese hypophosphite. The sodium salt is used primarily in electroless nickel plating. It is also used as a reducing agent, analytical reagent, polymerization catalyst, polymer stabilizer, and fire retardant. While the manganese salt is used primarily in nylon fiber production, it also has application as a chemical intermediate, they are not sold at retail.
