Cost estimates for closure and postclosure

1. Each owner or operator shall prepare separate written closure and postclosure estimates of the costs of hiring a third party to complete identified activities of the facility closure and postclosure plans. a. The initial cost estimates must be in current dollars, and cost estimates must be adjusted annually for inflation. b. The cost estimate for closure must equal the cost of closing the largest area requiring a final cover during the active life of the facility. c. The owner or operator shall increase the cost estimates if changes in the closure plan or postclosure plan increase the maximum costs of closure or postclosure care, respectively. The owner or operator may reduce a cost estimate for closure if it exceeds the maximum costs of closure during the remaining life of the facility or a cost estimate for postclosure care if it exceeds the maximum costs of postclosure during the remaining postclosure period. d. The cost estimate for postclosure must account for the total costs of postclosure care over the entire postclosure period, including the most expensive costs of postclosure during the postclosure period. 2. Each owner or operator shall prepare a new closure or postclosure cost estimate whenever any of the following occurs: a. Changes in operating plans or facility design affect the closure or postclosure plans; b. There is a change in the expected year of closure; or c. The department directs the owner or operator to revise the closure or postclosure plan.