b) In conducting best efforts to obtain off-site access, an owner or operator must, at a minimum, send a letter by certified mail to the owner of any off-site property to which access is required, stating:

1. 1) Citation to Title XVI of the Act stating the legal responsibility of the owner or operator to remediate the contamination caused by the release;
2. 2) That, if the property owner denies access to the owner or operator, the owner or operator may seek to gain entry by a court order pursuant to Section 22.2c of the Act;
3. 3) That, in performing the requested investigation, the owner or operator will work so as to minimize any disruption on the property, will maintain, or its consultant will maintain, appropriate insurance and will repair any damage caused by the investigation;
4. 4) If contamination results from a release by the owner or operator, the owner or operator will conduct all associated remediation at its own expense;
5. 5) That threats to human health and the environment and diminished property value may result from failure to remediate contamination from the release; and

c) An owner or operator, in demonstrating that the requirements of this Section have been met, must provide to the Agency, as part of the corrective action completion report, the following documentation:

1. 1) A sworn affidavit, signed by the owner or operator, identifying the specific off-site property involved by address, the measures proposed in the corrective action plan that require off-site access, and the efforts taken to obtain access, and stating that the owner or operator has been unable to obtain access despite the use of best efforts; and
2. 2) A copy of the certified letter sent to the owner of the off-site property pursuant to subsection (b) of this Section.

d) In determining whether the efforts an owner or operator has made constitute best efforts to obtain access, the Agency must consider the following factors:

1. 1) The physical and chemical characteristics, including toxicity, persistence and potential for migration, of applicable indicator contaminants at the property boundary line;
2. 2) The hydrogeological characteristics of the site and the surrounding area, including the attenuation capacity and saturation limits of the soil at the property boundary line;
3. 3) The nature and extent of known contamination at the site, including the levels of applicable indicator contaminants at the property boundary line;
4. 4) The potential effects of residual contamination on nearby surface water and groundwater;
5. 5) The proximity, quality and current and future uses of nearby surface water and groundwater, including regulated recharge areas, wellhead protection areas, and setback zones of potable water supply wells;
6. 6) Any known or suspected natural or man-made migration pathways existing in or near the suspected area of off-site contamination;
7. 7) The nature and use of the part of the off-site property that is the suspected area of contamination;
8. 8) Any existing on-site engineered barriers or institutional controls that might have an impact on the area of suspected off-site contamination, and the nature and extent of such impact; and