“explosive article” means an article (for example, a bomb or a firework) containing one or more explosive substances;

“explosive substance” means a substance or preparation, not including a substance or preparation in a solely gaseous form or in the form of vapour, which is —

a

capable by chemical reaction in itself of producing gas at such a temperature and pressure and at such a speed as could cause damage to surroundings; or

b

designed to produce an effect by heat, light, sound, gas or smoke, or a combination of these as a result of a non-detonative, self-sustaining, exothermic chemical reaction;

“preparation” means a mixture of two or more substances or a solution of any substance or substances;