What is the purpose of using an inert gas like carbon dioxide in confined spaces?

Using an inert gas like carbon dioxide in confined spaces primarily serves to purge explosive vapors. Inert gases are not reactive and do not support combustion, meaning they can safely displace oxygen and flammable gases that may be present in a confined space. By introducing carbon dioxide, the level of oxygen can be reduced to a non-combustible state which helps minimize the risk of an explosion or fire. This is particularly critical in environments where flammable substances are stored, and where the potential for ignition exists.

Regarding the other options, increasing oxygen levels is not a function of inert gases, as they typically displace oxygen rather than add to it. Supporting combustion is contrary to the purpose of using an inert gas; instead, it acts to suppress it. Enhancing visibility is also not a function of carbon dioxide or inert gases, as their primary role is safety related to combustion and not improving lighting conditions. Thus, using an inert gas effectively contributes to maintaining a safe working environment in confined spaces by managing the risk of explosive vapors.