PURPOSE: This rule describes the first steps to stop the spread of the release and finding the extent of the release.

1. (1) Unless directed to do otherwise by the department, owners and operators must perform the following abatement measures:

   1. (A) Remove as much of the regulated substance from the underground storage tank

2. (UST) system as is necessary to prevent further release to the environment;

   1. (B) Visually inspect any above-ground releases or exposed below-ground releases and prevent further migration of the released substance into surrounding soils and groundwater;
   2. (C) Continue to monitor and mitigate any additional fire and safety hazards posed by vapors or free product that have migrated from the UST excavation zone and entered into subsurface structures such as sewers or basements;
   3. (D) Remedy hazards posed by contaminated soils that are excavated or exposed as a result of release confirmation, site investigation, abatement or corrective action activities. If these remedies include treatment or disposal of soils, the owner and operator must comply with applicable state and local requirements;
   4. (E) Measure for the presence of a release where contamination is most likely to be present at the UST site, unless the presence and source of the release have been confirmed in accordance with the site check required by 10 CSR 20-10.052(1)(B) or the closure site assessment of 10 CSR 20-10.072(1). In selecting sample types, sample locations and measurement methods, the owner and operator must consider the nature of the stored substance, the type of backfill, depth to groundwater and other factors as appropriate for identifying the presence and source of the release; and 10 CSR 20-10
   5. (F) Investigate to determine the possible presence of free product and begin free product removal as soon as practicable in 10 CSR 20-10.064.
3. (2) Within twenty (20) days after release confirmation, owners and operators must submit a report to the department summarizing the initial abatement steps taken under section (1) of this rule and any resulting information.

AUTHORITY: sections 319.109, RSMo Supp. 1989 and 644.026, RSMo Supp. 1993.* Original rule filed April 2, 1990, effective Sept. 28, 1990. *Original authority: 319.109, RSMo 1989 and 644.026, RSMo 1972, amended 1973, 1987, 1993.