"Explosives" means any chemical compound or mechanical mixture that is commonly used or intended for the purpose of producing an explosion, and which contains any oxidizing or combustible units or other ingredients in such proportions, quantities or packing that an ignition by fire, by friction, by concussion, by percussion or by detonation of any part of the compound mixture may cause such a sudden generation of highly heated gases that the resultant gaseous pressures are capable of producing destructible effects on contiguous objects or of destroying life or limb.