74:56:03:22Release investigation

and confirmation. Release investigation and confirmation requirements are as follows: (1) After consultation with the department, all suspected releases must be immediately investigated by the owners or operators using one or more of the following procedures: (a) Initiation of a site investigation of the suspected release incident to determine the total extent of release; (b) In case of an AST system with secondary containment, an investigation of a possible release into the area between the AST system and the secondary containment; (c) Internal tank inspection; (d) Investigation in the following manner of releases detected by a failed tank or piping test: (i) A check of inventory records to detect a discrepancy that indicates a release may have occurred; (ii)Isolation from the tank and retesting of the piping within seven days after the initial testing; (iii) Isolation from the piping and retesting of the tank within seven days after the initial testing; and (iv) Laboratory analysis of soil samples for regulated substance contamination in the area of the suspected release; (e) In the case of a discrepancy during inventory reconciliation or any other suspected release, an investigation shall be conducted in the following manner: (i) A test of the AST systems and piping that is conducted within seven days after the initial reporting to the state to determine if a release may have occurred; and (ii)Laboratory analysis of soil samples for regulated substance contamination in the area of the suspected release; (f) Other investigative procedures with prior approval of the department; (2) When a release of a regulated substance is suspected, the state may require the owners or operators to test the AST systems and piping for tightness or structural soundness or require a site investigation to ascertain the location, magnitude, and effect of the releases.

Source: 14 SDR 76, effective November 29, 1987; 18 SDR 62, effective October 10, 1991; transferred from § 74:03:30:22, July 1, 1996.