Name one sign that a fuel storage tank may be leaking.

Unexplained drops in fuel levels are a significant indicator that a fuel storage tank may be leaking. When a tank begins to leak, it will show a consistent decrease in fuel levels that cannot be accounted for by normal usage, sales, or evaporation. This unexplained loss prompts further investigation into the integrity of the storage system. Identifying a drop that isn't explained by dispensing fuel can indicate an environmental risk, financial loss, or potential regulatory non-compliance, necessitating immediate attention to prevent further issues.

Separately, while options such as increased fuel sales or regular inspection reports are related to fuel management, they do not serve as direct indicators of a leaking tank. Similarly, color changes in the fuel may suggest contamination but aren't an evident sign of a leak in the storage tank itself. Therefore, recognizing unexplained drops in fuel levels is crucial in monitoring tank health and taking necessary corrective action.