(2) A date determined by the department, based on the diminishing number of mercury-containing lights collected by the program reaching a de minimis level where the continued expense and environmental cost of implementing the program would result in continued costs that outweigh the benefits of continuing the program, as calculated in a cost-benefit analysis consistent with the requirements of RCW
34.05.328. Unless the department and stewardship organization agree to a different cessation date prior to 2035 without carrying out a cost-benefit analysis, the department must conduct a cost-benefit analysis under this subsection to be completed during calendar year 2031.