Which type of gas poses a significant risk of explosion if not handled properly?

Natural gas poses a significant risk of explosion if not handled properly due to its flammable nature. It is primarily composed of methane, which is highly combustible and can easily ignite when mixed with air within specific concentration ranges. If there is a leak in a gas line or storage container, natural gas can accumulate in enclosed spaces, increasing the risk of explosion when ignited by a spark or flame.

In contrast, carbon dioxide and nitrogen are largely inert and do not support combustion; consequently, they do not pose an explosion risk in the same manner as natural gas. While oxygen is essential for combustion, it is not flammable on its own; rather, it fuels the flames of other combustible materials. Therefore, the careful handling and monitoring of natural gas is crucial to prevent hazardous situations, making it the correct answer in terms of explosion risk.