Ethylenediamine dihydroiodide (EDDI) is a salt of ethylene diamine and hydrogen iodide. It is used as a pet food additive and cattle feed additive to prevent iodine deficiency. It has high bioavailability. It is a colorless to light yellow crystalline powder. Its chemical formula is C2H6N2.2HI. Its CAS number is [ ]. It is nonflammable, but iodine may be released during a fire. It is soluble in water.
Other iodine supplements in animal feed are calcium iodate (most stable) and potassium iodide (most water-soluble, least stable). EDDI is restricted to GRAS as a nutrient source of iodine only. FDA suggests a limit of intake to 50 mg/head/day. 
EDDI may react with sulfates and release free iodine.