PURPOSE: This rule describes the requirements of a site assessment to determine whether there has been a release from the underground storage tank system.

PUBLISHER’S NOTE: The secretary of state has determined that the publication of the entire text of the material which is incorporated by reference as a portion of this rule would be unduly cumbersome or expensive. This material as incorporated by reference in this rule shall be maintained by the agency at its headquarters and shall be made available to the public for inspection and copying at no more than the actual cost of reproduction. This note applies only to the reference material. The entire text of the rule is printed here.

1. (1) Before permanent closure or a change in service is completed, owners and operators must measure for the presence of a release where contamination is most likely to be present at the underground storage tank (UST) site. In selecting sample types, sample locations, and measurement methods, owners and operators must consider the method of closure, the nature of the stored substance, the type of backfill, the depth to groundwater, and other factors appropriate for identifying the presence of a release.
2. (2) If contaminated soils, contaminated groundwater, or free product as a liquid or vapor is discovered under section (1) of this rule, or by any other manner, owners and operators must begin site investigation and corrective action in 10 CSR 26-2.070–10 CSR 26-2.083.

3. (3) Owners and operators shall follow a written procedure.

   1. (A) Until December 31, 2012, owners and operators may use the department’s Risk- Based Corrective Action for Petroleum Storage Tanks guidance document dated February 2004, as amended March 8, 2005, by Notice of Modifications to the Process and Interim Guidance Pertaining to Application of the New Soil Type Dependent Tier 1 Risk- Based Target Levels; the March 18, 2005, Soil Type Determination Guidelines; the March 3, 2005, Table 3-1 Default Target Levels; the April 2005 Table 4-1 Soil Concentration Levels to Determine the Need for Groundwater Evaluation During Tank Closure; the February 2005 Tables 7-1(a) through 7-12(c) Tier 1 Risk-Based Target Levels; and the April 21, 2005, Soil Gas Sampling Protocol. The guidance and amendments were published by the Department of Natural Resources, PO Box 176, Jefferson City, MO 65102-0176, and are hereby incorporated by reference. This rule does not incorporate any subsequent amendments or additions.
   2. (B) Other written procedures may be used with prior written approval of the department. AUTHORITY: section 319.111, RSMo 2000, and section 319.137, RSMo Supp. 2010.* This rule originally filed as 10 CSR 20- 10.072. Original rule filed April 2, 1990, effective Sept. 28, 1990. Amended: Filed Aug. 3, 1993, effective April 9, 1994. Moved and amended: Filed April 15, 2011, effective Dec. 30, 2011. *Original authority: 319.111, RSMo 1989 and 319.137, RSMo 1989, amended 1993, 1995, 2004.