16th July 2014 CSB released their final case study on metal dust explosion (December 9, 2010) which resulted in three deaths and one injury. The facility milled and processed scrap titanium and zirconium metal.
CSB findings reveal that solid organic materials and most metals will cause explosion if the particle size is small enough and are dispersed in sufficient concentration in a confined area.
Read full report here
Transport regulations lists Titanium powder and Zirconium as below
TITANIUM POWDER, DRY – Class 4.2 UN Number 2546
TITANIUM POWDER, WETTED – Class 4.1 UN Number 1352
ZIRCONIUM POWDER, DRY – Class 4.2 UN Number 2008
ZIRCONIUM POWDER, WETTED – Class 4.1 UN Number 1358
ZIRCONIUM POWDER, WETTED – Class 4.1 UN Number 1358
ZIRCONIUM, SCRAP – Class 4.2 UN Number 1932
ZIRCONIUM, SUSPENDED IN A FLAMMABLE LIQUID – Class 3 UN Number 1308