What is the purpose of pumping inert gas into the tank?

Pumping inert gas into the tank primarily serves to displace oxygen and flammable vapors. This practice is essential for maintaining safety during operations such as maintenance, cleaning, or while the tank is not in use. By replacing the oxygen and flammable vapors with an inert gas, such as nitrogen, the risk of combustion or explosion is significantly reduced.

Inert gases are non-reactive and help to create a safe environment within the storage tank, preventing any potential ignition sources from leading to hazardous conditions. This is particularly crucial in underground storage tanks (USTs), where vapors can accumulate and pose serious risks to safety and the environment.

In contrast, options like cooling the tank, cleaning, or pressurizing it do not capture the primary safety aspect that comes from displacing combustible vapors. Each of those processes might have different purposes and methods but do not specifically address the inherent dangers associated with the presence of oxygen in the tanks.