(a) The commission may not name a person as a responsible party for an enforcement action or require a person to reimburse remediation costs for a site if the commission has conducted an investigation of a site owned or operated by the person and as a result of the investigation has determined that:
(1) the contaminants that are the subject of investigation under this subchapter appear to originate from an up-gradient, off-site source that is not owned or operated by the person;
(2) additional corrective action is not required at the site owned or operated by the person; and
(3) the commission will not undertake a formal enforcement action in the matter.
(b) The commission may not name a land bank established under Chapter 379C, Local Government Code, as a responsible party for an enforcement action or require the land bank to reimburse remediation costs for a site if the commission has conducted an investigation of a site owned or operated by the land bank and as a result of the investigation has determined that:
(1) the contaminants that are the subject of investigation under this subchapter:
(A) appear to originate from an up-gradient, off-site source that is not owned or operated by the land bank; or
(B) appear to have been present on the site before the land bank purchased the site; and
(2) the land bank could not have reasonably known about the contaminants at the time the land bank purchased the site.