PURPOSE: The Missouri Clean Water Commission is responsible for adopting rules necessary to prevent, control, and abate potential discharge of contaminants to the waters of the state. Releases of petroleum and other regulated substances from aboveground 10 CSR 26-5

storage tanks and associated piping, primarily from ASTs located at service stations, marinas, bulk plants, and fleet fueling facilities, have been documented throughout the state. While the applicable Department of Agriculture regulations focus on prevention of such releases, there are currently no specific requirements for release response measures that must be taken to protect the environment and the waters of the state. The commission has determined release response measures to be necessary because, once a release has occurred, the nature of the contaminants is such that, without appropriate release response measures, there is a substantial threat that the discharged contaminants will pollute the waters of the state. The intent of the release response measures required by the rules in this chapter is to prevent any discharged contaminants from polluting the waters of the state. Further, this rule specifies the procedures for soil and groundwater investigations or characterization of the release at the site, and lists the requirements for corrective action plans for cleanup of releases from aboveground storage tank sites. In addition, this rule specifies the type of information required to be submitted by the owner or operator to the department, upon completion of these phases of activities.

1. (1) Site Characterization.

   1. (A) At the request of the department in response to a release, the owner or operator of an AST shall conduct a site characterization to include a full investigation 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 contamination in the groundwater if the Initial Release Response Report submitted in compliance with 10 CSR 26-5.020 documents any of the following:

      1. 1. Contaminated groundwater or surface

water above action levels;

1. 2. Contaminated soils above action lev-

els;

1. 3. Presence of free product; or
2. 4. Some other characteristic determined

by the department to require further investigation because of its potential to result in pollution of the waters of the state or a potential threat to human health and the environment.

1. (B) An owner or operator of an AST shall follow a written procedure for conducting the site characterization of the release site. The department’s Site Characterization Guidance Document may be used as a written procedure. Other written procedures may be used with prior written approval from the department.

1. (2) Site Characterization Reporting. A site characterization shall include, at a minimum, information about the site and the nature of the release. The site characterization report containing this information shall be submitted to the department within forty-five (45) days of date of the department’s request to conduct site characterization in subsection (1)(A) of this rule. The department may approve an alternative reporting schedule. This information shall include, but is not limited to, the following:

   1. (A) Data regarding the type of product released and an estimate of the quantity;

   2. (B) Data from available sources or site investigations concerning the following factors:

      1. 1. Surrounding land use;
      2. 2. The hydrogeologic characteristics of

the site and the surrounding area;

1. 3. Use and approximate locations of

wells affected or potentially affected by the release;

1. 4. Surface and subsurface soil condi-

tions at the site and the immediate surrounding area;

1. 5. Locations of subsurface utilities;
2. 6. The proximity, quality, and current

and potential future uses of nearby surface and groundwater;

1. 7. The potential effects of residual con-

tamination on nearby surface and groundwater; and

1. 8. Any additional relevant information

assembled while carrying out the steps required in 10 CSR 26-5.020 and this rule.

1. (3) Corrective Action. Based upon the results of the site characterization, the owner or operator of the AST may be required to submit to the department a plan for corrective action that provides for adequate protection of human health and the environment, as determined by the department. The owner or operator of the AST shall modify the plan as necessary to meet this standard.

   1. (A) If a plan is required, the owner or operator shall submit the plan within fortyfive (45) days or according to a schedule and format established by the department.
   2. (B) Even if not requested by the department, an owner or operator of an AST may elect to submit a corrective action plan.
   3. (C) Once a plan has been submitted, the department will review the corrective action plan to ensure that implementation of the plan will adequately protect human health and the environment. In making this determination, the department will consider the factors listed in subsection (2)(B) of this rule.
   4. (D) Upon written approval of the plan, or as directed by the department, the owner or Substance Storage Tanks

operator of the AST shall implement the plan, including any modifications to the plan made by the department. The owner or operator shall evaluate and report the results of implementing the plan in accordance with a schedule and in a format established by the department.

1. (E) An owner or operator of an AST may begin remediation of soil and groundwater prior to approval of the corrective action plan provided they:

   1. 1. Notify the department in writing of

their intention to begin cleanup;

1. 2. Comply with any conditions imposed

by the department, including cessation of remedial activities or mitigation of adverse consequences from cleanup activities; and

1. 3. Incorporate all self-initiated remedial

measures into the corrective action plan submitted to the department for approval.

1. (F) An owner or operator of an AST shall follow a written procedure for establishing a corrective action plan. The department’s Corrective Action Guidance Document may be used as a written procedure. Other written procedures may be used with prior written approval from the department.

AUTHORITY: section 319.137, RSMo Supp. 2010, and section 644.026, RSMo 2000.* This rule originally filed as 10 CSR 20- 15.030. Original rule filed Sept. 13, 2001, effective May 30, 2002. Moved and amended: Filed April 15, 2011, effective Dec. 30, 2011. *Original authority: 319.137, RSMo 1989, amended 1993, 1995, 2004; and 644.026, RSMo 1972, amended 1973, 1987, 1993, 1995, 2000.