Quote:
A Mackay man who stored propellant powders in an old bank safe in his gunroom woke to discover that the deflagration of propellant powders stored within the safe had bulged the safe door outward, allowing the gases to escape. The gases escaped with sufficient force to blow out a brick wall immediately beside the safe.
It is well known that ammunition can deteriorate with age to a stage where it will not reliably fire. It is not widely known that propellant powder deteriorates and decomposes with age. A retardant is added to powder to stop or delay decomposition. However, in time, the retardant loses its effectiveness, decomposition sets in a spontaneous combustion can occur. It appears that this was the case in this incident.