LPG is colourless and odourless and a strong "stenching" agent is added so that even a very small leak can be easily detected.
At a normal temperature, LPG is a gas. When subjected to modest pressure or cooling, it transforms into a liquid. As a liquid, it is easy to transport and store. Once it has been cooled or pressurised, LPG is usually stored in containers made of either steel or aluminium.