What is the proper action to take if a tank is unstable after being unloaded?

The proper action to take when a tank is unstable after being unloaded is to chock the tank to stabilize it. This action is important to prevent any potential accidents or further instability that could lead to dangerous situations, such as leaks or environmental hazards. Chocking the tank provides physical support, reducing the risk of movement and ensuring that it remains secure while other actions, like testing or removal, are considered. Stabilization is a crucial first step in managing any potential risks associated with an unstable tank, promoting safety for the operators and the surrounding environment.

Other actions, while they may seem beneficial in different contexts, do not address the immediate need for stability. For instance, leaving the tank unattended does not mitigate the risk of instability. Similarly, removing the tank or filling it with water may not be feasible or safe until the tank is properly stabilized. Thus, chocking it is the most effective and responsible approach in this scenario.