An American Petroleum Institute (API) 653 Tank Inspection is the petroleum storage industry process to determine tank hydraulic and structural integrity. Inspections are performed in accordance with API Standard 653.

Out-of-Service inspections include visual inspection of the tank floor, shell, and roof, and pit survey for topside corrosion on the floor plates. The inspections also include the following non-destructive examination procedures: magnetic flux leakage (MFL) scan of the floor for bottom side corrosion, and ultrasonic inspections of the floor, shell, and roof.

This project included API 653 Out-of-Service inspections of two tanks at Cold Brook Energy in Hampden, Maine.