Pyrophoric

Pyrophoric materials react so readily with oxygen or moisture in the air that they heat up and catch fire on their own. Examples include some finely divided metals, certain metal hydrides, alkyllithium and other organometallic reagents, and gases such as silane. The GHS has separate classes for pyrophoric liquids and pyrophoric solids, while pyrophoric gases are a sub-category of flammable gases (Category 1A) with the statement H232.

Because the fire starts without warning, the main controls are about keeping air away. Pyrophoric chemicals are usually supplied in sealed containers under an inert gas or in a solvent, and are transferred with syringes, cannulas, gloveboxes or other closed techniques. Even a small amount left on a needle, a wipe or a glove can ignite.

Training is critical. Anyone using these materials should know exactly how a given reagent behaves, what the planned quench procedure is, and what to do if a spill or fire occurs. Many pyrophorics react badly with water, so the wrong extinguisher can make things worse; the SDS names suitable and unsuitable extinguishing media.

Clothing matters too. Flame-resistant lab coats and appropriate gloves are common recommendations, since ordinary synthetic fabric can melt onto skin. Emptied containers are still hazardous because residue remains, and they need proper quenching or disposal.