Product inventory control must be conducted monthly to detect a release of what percentage of flow through plus an additional amount?

The requirement for conducting product inventory control monthly is based on the need to effectively monitor any potential releases from underground storage tanks (USTs). In this context, detecting a release of 1% of the product flow through each month is a critical threshold because it provides a reliable indicator of any discrepancies in inventory that may suggest a leak.

Monitoring for this specific percentage ensures that even small undetected leaks can be identified in a timely manner, reducing the risk of significant environmental contamination and compliance issues. The additional amount considered along with the 1% flow is crucial, as it allows for variability in operational processes or measurement errors that could falsely indicate a problem with the UST system. The 1% threshold is aligned with best practices in environmental management and regulatory compliance, emphasizing the importance of maintaining strict oversight over UST inventories to protect public health and the environment.

Thus, conducting monthly inventory checks to identify a release equal to 1% of the flow is an essential practice in maintaining the integrity and safety of underground storage tank systems.