An explosion is a very rapid chemical reaction. The gases rapidly expand and give off a lot of heat.
There are some situations where a worker is responsible for explosives. It can include things such as; ammunition, fireworks, detonators, etc. If this is the case extensive training is vital.
There are about 65 pure chemicals that are considered explosive. By pure it means that they are not mixed wih another chemical. The number of chemicals that can become explosive when mixed in different combinations is, in theory, countless. And this does not take into account such factors as heat, or impacts of containers. It is therefore imperative that only highly trained competent workers handle substances, which have explosive potential.
Just to give an indication of how common explosive chemicals are, these are a few that can easily be obtained, if not already in most people’s homes or workplace; gasoline, diesel, alcohol, furniture polish, paint and paint thinner, window and toilet cleaners, varnish, nail polish remover, pure oxygen, ammonium, sodium azide, nitroglycerine, and peroxide.