UN Number 1
UN Number 1 : UN number is a four-digit number for the labelling of hazardous substances in international transport. Most hazardous substances possess an unique UN number (e.g. UN1017: chlorine). Some UN numbers denote groups of substances (e.g. UN1993: Flammable liquid n.o.s.). The complete list of UN numbers can be found in the ADR/RID regulation