What must owners and operators do to notify the EPA at least 30 days prior to permanently closing an UST system?

Owners and operators must notify the EPA at least 30 days prior to permanently closing an underground storage tank (UST) system, and they have the flexibility to use multiple communication methods to accomplish this. This includes calling the EPA, mailing the notification via the U.S. Postal Service, or emailing the agency. The important aspect here is that the notification must be completed in a timely manner to allow the EPA to process the closure and ensure compliance with regulations regarding the proper procedures for closing a UST system. Each method is valid, and the choice to use one over the others may depend on factors like urgency or the preferred communication style of the owner or operator. Therefore, the inclusion of "any of the above methods" accurately reflects the requirements set forth by the EPA for this notification process.