What is the primary function of an overfill alarm?

The primary function of an overfill alarm is to alert operators of high tank levels. This safety feature is crucial for underground storage tanks (USTs) to prevent spills and overflow, which can lead to environmental contamination and regulatory violations. The alarm activates when the tank reaches a predefined high level, allowing operators to take immediate action to prevent an overfill situation.

Monitoring fuel levels effectively ensures safe operations, compliance with environmental regulations, and helps maintain the integrity of the UST system. In contrast, other options such as signaling low fuel levels, controlling tank pressure, or monitoring temperature fluctuations do not directly relate to the primary purpose of preventing overfills, which focuses specifically on alerting operators when the tank is full or nearing capacity.