In compact form, titanium is completely harmless - in powder form, however, there is a high risk of fire. Light metal powders such as titanium, but also magnesium or aluminium, are extremely flammable to the point of spontaneous combustion. The flammability depends on factors such as the grain size. In general, the finer the titanium powder is distributed, the greater the risk.
The swirled up titanium dust reacts with the room air even at room temperature. The resulting heat of reaction ultimately leads to spontaneous combustion. Powder residues that settle on work clothing can even cause clothing to burn. A single spark, for example from a grinder, is sometimes enough to trigger this.
