Section 5B. (a) There is hereby established a pooled risk program for extraordinary and unanticipated special education costs to be administered by the department. The board of education shall promulgate regulations necessary for the operation of the program.

(b) A local or regional school district may elect to participate in the pooled risk program by vote of the school committee by a date established by regulations of the department. Districts shall be given at least one opportunity each year to join the program but districts shall elect to participate for a period of not less than five years.

(c) The commissioner shall annually establish the premiums to be paid by each participating district. Such premiums shall take into account the number of students enrolled in the district, the district's evolving history of claims on the fund and such other factors as are deemed appropriate. A district's premiums shall increase in response to that district's claims made on the fund in accordance with regulations promulgated by the board. Commonwealth appropriations shall provide a match of up to $1 per dollar paid in premiums by participating districts.

(d) The comptroller shall establish on the books of the commonwealth a special education pooled risk program trust fund. At the direction of the commissioner, premium payments due from participating districts shall be deducted from said district's quarterly local aid distributions and deposited in said trust fund. Any amounts appropriated for the purposes of this program, including any amount appropriated for the purpose of insuring short-term solvency, shall also be transferred into said trust fund.

(e) Any funds remaining in the trust fund at the end of a fiscal year shall be carried forward into the following fiscal year and shall remain available for expenditure without further appropriation.

(f) Districts may submit claims for payment not to exceed 75 per cent of the amount by which the district's current year total special education expenses exceed 110 per cent of the district's average total special education expenses of the prior three years. For the purposes of this section, total special education expenses shall include instructional costs and private school tuition costs but shall not include transportation costs. Claims shall be subject to review and approval by the commissioner. Approved claims shall be paid from the trust fund.

(g) The commissioner may make such adjustments as are necessary to premiums and claims to account for reimbursements received under any other state or federal programs and to adjust prior year amounts based on final reported costs for the fiscal year.

(h) Commonwealth charter schools may participate in the program in the same manner as local and regional school districts provided that any payments due to the trust fund may be deducted from tuition payments otherwise to be deducted from district quarterly local aid distributions pursuant to subsection (nn) of section 89 of chapter 71. Said payments shall be deposited in said trust fund.

(i) A reasonable amount of administrative costs may be expended annually from the trust fund for the administration of the program.