Purity: 99.9% (REO) CAS Number: 7440-52-0 UN Number: UN3178 Hazard Class: 4.1 Packing Group: II Harmonized Tariff Code:  2805.30 Risk Phrases: 11-15 Flammable. Contact with water liberates highly flammable gases. Safety Phrases: 7/8-43 Keep container tightly closed and dry.