PURPOSE: This rule describes the procedures for soil and groundwater investigations.

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) Owners and operators must conduct investigations of the release, the release site, and the surrounding area to determine the full extent and location of soils contaminated by the release and the presence and concentrations of dissolved product contamination in the groundwater if any of the following conditions exist:

   1. (A) There is evidence that groundwater wells have been affected by the release (for example, as found during release confirmation or previous corrective action measures);
   2. (B) Free product is found to need recovery in compliance with 10 CSR 26-2.075;
   3. (C) There is evidence that contaminated soils may be in contact with groundwater as found during the initial response measures or investigations required under 10 CSR 26- 2.070–10 CSR 26-2.075;
   4. (D) Contaminant concentrations in soil or groundwater exceed the Default Target Levels in Table 3-1 of the guidance referenced at paragraph (3)(C)1. of this rule; or
   5. (E) The department requests an investigation based on the potential effects of contaminated soil or groundwater on nearby surface and groundwater resources.
2. (2) Owners and operators must submit the information collected under section (1) of this rule as soon as practicable or in accordance with a schedule established by the department.

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

   1. (A) For releases that occurred or were discovered on or after the effective date of this rule, owners and operators shall use the document referenced at paragraph (3)(C)1. of this rule or, with prior written approval of the department, another written procedure.
   2. (B) For releases that occurred or were discovered prior to the effective date of this rule, Substance Storage Tanks

owners and operators may use—

1. 1. The documents referenced at para-

graph (3)(C)2. of this rule, provided—

1. A. Prior to the effective date of this

rule, the owner or operator received the department’s written approval of a work plan for site characterization, risk assessment, or corrective action related to the release; and

1. B. The owner or operator implements

or implemented the approved work plan within one (1) year of the date of the department’s approval of the plan or in accordance with a different schedule approved by the department;

1. 2. The document referenced at para-

graph (3)(C)1. of this rule; or

1. 3. With the prior written approval of the

department, another written procedure.

1. (C) Written Procedures.

   1. 1. Missouri Risk-Based Corrective

Action Process for Petroleum Storage Tanks guidance document, October 17, 2013, which is hereby incorporated by reference without any subsequent amendments or additions, and is published by the Department of Natural Resources, PO Box 176, Jefferson City, MO 65102-0176.

1. 2. Missouri Risk-Based Corrective Action

Process for Petroleum Storage Tanks, 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, which are hereby incorporated by reference without any subsequent amendments or additions, and are published by the Department of Natural Resources, PO Box 176, Jefferson City, MO 65102-0176.

AUTHORITY: sections 319.109 and 319.137, RSMo Supp. 2013.* This rule originally filed as 10 CSR 20-10.065. 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. Amended: Filed June 17, 2013, effective Feb. 28, 2014. *Original authority: 319.109, RSMo 1989, amended 1995, 2004, 2008 and 319.137, RSMo 1989, amended 1993, 1995, 2004.