(1) Following initiation of initial actions under section 21307, the owner or operator that is liable under section 21323a shall complete the requirements of this part and submit related reports or executive summaries detailed in this part to address the contamination at the site. At any time that sufficient corrective action has been undertaken to address contamination, the owner or operator that is liable under section 21323a shall complete and submit a site closure report pursuant to section 21312a and omit the remaining interim steps.

    (2) In addition to the reporting requirements specified in this part, the owner or operator that is liable under section 21323a shall provide 48-hour notification to the department prior to initiating any of the following activities:

    (a) Soil excavation.

    (b) Well drilling, including monitoring well installation.

    (c) Sampling of soil or groundwater.

    (d) Construction of treatment systems.