a) When closure of a unit is completed, the operator shall submit to the Agency:

1. 1) Documentation concerning closure of the closed unit including plans or diagrams of the unit as closed and date closure was completed.
2. 2) An affidavit by the operator and the seal of a professional engineer that the unit has been closed in accordance with the closure plan and all requirements of 35 Ill. Adm. Code 811.

b) When the Agency determines, pursuant to the information received pursuant to subsection (a) and any Agency site inspection, that the unit has been closed in accordance with the specifications of the closure plan, and the closure requirements of this Part, the Agency shall:

1. 1) Issue a certificate of closure; and
2. 2) Specify the date the postclosure care period begins, based on the date that closure was completed.