Release detection method uses sensors that detect petroleum in soil. Which option correctly identifies this method?

• A. Vapor monitoring
• B. Pressure testing
• C. Visual inspection
• D. Tank testing

Answer: (A)

Vapor monitoring is the method that uses sensors to detect petroleum vapors in soil. When a leak occurs, volatile components from the fuel migrate into the surrounding soil gas, and detectors placed in soil or in monitoring wells pick up elevated hydrocarbon vapors, often triggering an alarm. This directly matches the idea of sensors detecting petroleum in soil, providing an early indication of a release. The other options focus on testing the tank or looking for signs rather than sensing vapors: pressure testing checks if the system holds pressure, visual inspection relies on surface observations, and tank testing assesses the tank itself.