What action regarding vent lines is required for a UST in temporary closure?

• A. Close vent lines
• B. Leave vent lines open and functioning
• C. Cap vent lines
• D. Remove vent lines

Answer: (B)

Vent lines must be left open and functioning during temporary closure. They relieve vapor pressure as temperatures change and prevent buildup inside the tank, reducing the risk of leaks or vapor hazards. Closing, capping, or removing vent lines would trap vapors and pressure, creating safety and regulatory problems.