What is a common symptom indicating propane tank overfilling?

A common symptom indicating propane tank overfilling is the presence of a strong propane odor accompanied by a hissing sound. When a tank is overfilled, liquid propane can escape through the relief valve or other openings, which creates this noticeable hissing noise. The distinct, pungent smell of propane is a safety feature designed to alert individuals to the presence of gas, as propane itself is odorless. Therefore, the combination of an odor and hissing sound serves as a critical warning sign of overfilling and potential danger, prompting immediate attention and action to prevent hazardous situations.

In contrast, the other options do not specifically correlate with overfilling. A green gas flame typically indicates improper combustion or appliance issues rather than a warning for tank overfilling. Temperature fluctuations can occur due to various factors unrelated to overfilling, such as changes in ambient conditions or system operation. Lastly, increased pressure in pipes can be the result of overfilling but is not a direct symptom; it could also stem from other issues within the system.