|(a) Voluntary cleanup work plans and reports shall meet all the requirements for work plans and reports set forth in 30 TAC 350 of this title (relating to Texas Risk Reduction Program). Contaminated media within the investigation area shall be addressed according to the appropriate established technical standards. (b) The requirements of subsection (a) of this section apply to a partial response action when a contaminant release originating from a partial response action area has migrated onto property owned or controlled by others. (c) The requirements of subsection (a) of this section apply to all voluntary cleanup response actions with the following exceptions: (1) When a person demonstrates to the satisfaction of the executive director that the source of contamination is from off-site and the person did not cause the release, the person may address only contamination on the site or the partial response action area within the site according to the appropriate established technical standards. (2) When a contaminant release is present outside the site or partial response action area, but on property owned or otherwise controlled by the applicant, addressing the areal extent of contamination outside the site or partial response action area is not required under the Voluntary Cleanup Program; however, the contaminant release within the partial response action area shall be addressed according to the appropriate established technical standards.