A pyrophoric substance (from Greek purophoros, "fire-bearing") will ignite spontaneously.
Pyrophoric scale is a material that can be burnt or ignited spontaneously when in contact with air, if struck or scratched.
Its a chemical hazard
Health hazard choking hazard
Class 1 materials are explosives.Materials that have an explosive hazard are in Hazard Class 1.
Fine powders of hafnium are pyrophoric.
Neptunium as a powder is pyrophoric.
Plutonium is pyrophoric as a fine powder.
Mihail Demestihas has written: 'Simulations to predict the countermeasure effectiveness of using pyrophoric type packets deployed from TALD aircraft'
Finding foreign objects in food served anywhere is a health and safety hazard.
biological
Chemical