|(a) The owner or operator shall provide a detailed written cost estimate, in current dollars, showing the cost of hiring a third party to close the largest waste fill area that could potentially be open in the year to follow and those areas that have not received final cover in accordance with the final closure plan. For any landfill this means the completion of the final closure requirements for active and inactive fill areas. The owner or operator shall submit the cost estimate for financial assurance with any new permit application, with any application for a permit transfer, and as a modification for all existing municipal solid waste permits that remain in effect after October 9, 1993. (1) The owner or operator shall review the facility's permit conditions on an annual basis and verify that the current active areas match the areas on which closure cost estimates are based. (2) An increase in the closure cost estimate and the amount of financial assurance provided under subsection (b) of this section shall be made if changes to the final closure plan or the landfill conditions increase the maximum cost of closure at any time during the remaining active life of the unit. (3) A reduction in the closure cost estimate and the amount of financial assurance provided under subsection (b) of this section may be approved if the cost estimate exceeds the maximum cost of closure at any time during the remaining life of the unit and the owner or operator has provided written notice to the executive director of the situation that includes a detailed justification for the reduction of the closure cost estimate and the amount of financial assurance. The owner or operator may request a reduction in the cost estimate and the financial assurance as a permit modification. (b) The owner or operator of any municipal solid waste unit shall establish financial assurance for closure of the unit in accordance with Chapter 37, Subchapter R of this title (relating to Financial Assurance for Municipal Solid Waste Facilities). Continuous financial assurance coverage for closure shall be provided until the facility is officially placed under the post-closure maintenance period and all requirements of the final closure plan have been approved as evidenced in writing by the executive director.