(a) Except as provided in Section 25209.6, no person shall place or dispose of hazardous waste in a land treatment unit if any of the following conditions exist:

1. (1) Hazardous constituents have migrated from the land treatment unit into the vadose zone beneath or surrounding the treatment zone or into the waters beneath or surrounding the treatment zone.
2. (2) There is evidence that a hazardous constituent in the waste discharged to the land treatment unit has not been or will not be completely degraded, transformed, or immobilized in the treatment zone.
3. (3) There is a significant potential for hazardous constituents to migrate from the land treatment unit into a potential source of drinking water.

(b) The owner or operator of a land treatment unit shall do all of the following:

1. (1) Periodically, at the request of the department, and at least annually, submit information the department may require in order to evaluate whether the conditions set forth in paragraph (1) or (2) of subdivision (a) are not present. The information to be submitted to the department shall include, but is not limited to, a sufficient number of soil core samples in, beneath, and surrounding the treatment zone of the land treatment unit to detect any hazardous constituents which may have migrated from the treatment zone. The department may adopt regulations requiring additional or more frequent testing.
2. (2) Within 72 hours of detecting and confirming the existence of either of the conditions identified in paragraph (1) or (2) of subdivision (a), or the presence of factors that render the owner or operator unable to continue satisfying the variance requirements of subdivision (b) of Section 25209.2, report to the department describing the full extent of the owner’s or operator’s findings.

(c) Upon receiving notice pursuant to paragraph (2) of subdivision (b), or upon the independent confirmation by the department, the department shall order the owner or operator to cease operating the land treatment unit. The owner or operator shall not resume operating the land treatment unit and shall close the land treatment unit unless one of the following actions is taken:

1. (1) The owner or operator completes appropriate removal or remedial actions to the satisfaction of the department and the owner or operator submits to the department, and the department approves, an application for a permit or variance modification to modify the operating practices at the facility to maximize the success of degradation, immobilization, or transformation processes in the treatment zone, if the owner or operator has not previously submitted an application for a permit or variance modification pursuant to this paragraph.
2. (2) The owner or operator completes appropriate removal or remedial actions and equips the land treatment unit with liners, leachate collection and removal systems, a groundwater monitoring system, and a vadose zone monitoring system that satisfy the requirements of Section 25209.5, if the land treatment unit has not already been equipped with these systems.