The volume is intended for use by hazardous waste facility owners/operators who prepare closure and post-closure cost estimates for treatment, storage, and incineration facilities and by regulatory officials who review these cost estimates for 40 CFR Parts 264 and 265 Subpart H. The volume's purpose is to provide a framework for developing the closure cost estimate for treatment and storage units (contains, tanks), and incinerators. The volume contains worksheets for estimating closure costs for treatment/storage units as well as summary worksheets for totalling facility costs. For those cases where tank facilities must also prepare most-closure estimates, post-closure estimates, post-closure worksheets are also provided in the volume.