It's high time you read the MSDS, unless of course you enjoy Delta fires.
SODIUM METAL
MSDS Number: S2594 --- Effective Date: 08/02/00
1. Product Identification
Synonyms: Sodium; Natrium
CAS No.: 7440-23-5
Molecular Weight: 22.99
Chemical Formula: Na
3. Hazards Identification
Emergency Overview
DANGER! FLAMMABLE SOLID. CORROSIVE. WATER REACTIVE. CATCHES FIRE IF EXPOSED TO AIR. HARMFUL OR FATAL IF SWALLOWED. HARMFUL IF INHALED OR ABSORBED THROUGH SKIN. CONTACT MAY CAUSE BURNS TO ALL BODY TISSUE.
I've never seen sodium spontaneously combust. Cesium, OTOH, that got going darn near as soon as it's taken out of the shipping oil.
We don't look at cesium compounds any more...
Furthermore, we don't just leave chunks of sodium lying out on the bench. When we're using it, we hustle. That probably helps.
I do research work with nickel metal hydride batteries... Those are really fun, because of all the H2 gas boiling off of the metal matrix.