With respect to a project which the commissioner has determined pursuant to paragraph g of subdivision five of section 27-1313 of this chapter to be eligible for funding, funding by the state shall be up to an amount of seventy-five percent of the eligible cost and the commissioner and the municipality shall enter into a contract which, in addition to such other terms and conditions that the commissioner may deem to be appropriate, provides as follows:

1. The current estimate of the cost of the project as determined by the commissioner at the time of execution of the agreement.

2. An agreement by the commissioner to periodically reimburse the municipality for costs incurred during the progress of the project. Such payments shall be subject to final computation and determination of the total state share of the eligible costs of the entire project.

3. An agreement by the municipality to proceed expeditiously with and complete the project in accordance with plans approved for payment of the municipality's share of the project cost.

4. A provision that in the event that any federal payments and responsible party payments become available which were not included in the calculation of the state share pursuant to subdivision two of this section, the amount of the state share shall be recalculated accordingly and the municipality shall pay to the state for deposit in the design and construction account of the hazardous waste remedial fund established under section ninety-seven-b of the state finance law the amount by which the state payment actually made exceeds the recalculated state share.

5. For purposes of this section, the term "eligible cost" means the non-federal share of the approved project cost less amounts collected from responsible parties as contemplated by title thirteen of article twenty-seven of this chapter.