When must UST owners seek approval from the EPA for UST service changes?

UST owners are required to seek approval from the EPA before making any changes to UST services because such changes could impact the environmental safety and regulatory compliance of the storage system. The EPA's regulations are designed to ensure that any alterations to how the UST operates do not create potential hazards that could lead to leaks or contamination of the surrounding environment.

This requirement for prior approval is essential for maintaining accountability and ensuring that all changes are evaluated for compliance with environmental laws and standards. It allows the EPA to assess the potential impacts of the change, ensuring that the UST continues to meet safety and environmental protection guidelines.

The other options suggest actions after the fact or under specific circumstances that do not capture the full scope of the requirement to notify the EPA before any modifications are made. Because of this regulatory framework, seeking approval before making changes is critical for UST owners to uphold their responsibility in preventing environmental harm.