(a) To determine the full extent and location of soils contaminated by the release, the presence and concentrations of dissolved regulated substance contamination in the groundwater, and the risk associated with the release, owners and operators must conduct investigations of the release, the release site, and the surrounding area (including adjacent areas not under ownership by the owner or operator) as necessary to determine the extent of the release if any of the following conditions exist:
  (1) there is evidence that groundwater wells have been affected by the release (e.g., as found during release confirmation or previous corrective action measures);
  (2) Non-Aqueous Phase Liquid is found to need recovery in compliance with §334.79 of this title (relating to Removal of Non-Aqueous Phase Liquids (NAPLs));
  (3) there is evidence that contaminated soils may be in contact with groundwater (e.g., as found during conduct of the initial response measures or investigations required under §§334.75-334.79 of this title (relating to Reporting and Cleanup of Surface Spills and Overfills; Initial Response to Releases; Initial Abatement Measures and Site Check; Site Assessment; and Removal of Non-Aqueous Phase Liquids (NAPLs)); or
  (4) the agency requests an investigation, based on the potential effects of contaminated soil or groundwater on nearby surface water or groundwater resources.
(b) Owners and operators must submit the information collected under subsection (a) of this section as soon as practicable, or in accordance with a schedule established by the agency.

Source Note: The provisions of this §334.80 adopted to be effective September 29, 1989, 14 TexReg 4714; amended to be effective November 8, 1995, 20 TexReg 8800; amended to be effective November 23, 2000, 25 TexReg 11442