Section 15. The commission may negotiate with and purchase on such terms as it deems to be in the best interest of the commonwealth and its active and retired employees and their dependents eligible under this chapter, from one or more insurance carriers authorized to sell health insurance in the commonwealth, a policy or policies providing basic and extended coverage for catastrophic illness such as cancer and other dread diseases as may be included from time to time by the commission. Such insurance shall provide basic and extended coverage including, but not limited to, ambulance services, in-patient and out-patient hospital services, blood and plasma, medicines and drugs, x-ray and other related treatments, nursing care, surgical, medical and other licensed practitioners' services, services of institutions providing rehabilitative care, or nursing or convalescent home care, and, for custodial care necessitated as a result of an illness covered under such policy or policies of insurance.

The commission shall negotiate a contract that assures sound financial stability consistent with insurance risks for long-term catastrophic illnesses, and shall be for a period of time and from time to time continuously without interruption of coverage; but any such contract with a carrier may be terminated by the commission provided that reasonable advance notice is given by the commission as provided in said policy or policies of insurance. The scope of insurance coverage under this section may relate to other health insurance coverages and experience accounting as provided in appropriate sections of this chapter, in order to attain the broadest possible basis of risk and protection.

Payment of premiums for catastrophic illness insurance provided in this section shall be made by the active and retired employee or surviving spouse thereof with no contribution by the commonwealth, and the method for such payments shall be as provided in sections eight, ten, ten B, ten C, eleven, twelve and fourteen, as may be applicable. Any dividend, refund or its equivalent accepted by the commission from the carrier or carriers shall be applied as provided in section nine.

Any policy or policies issued pursuant to this section shall provide that on termination of employment of an employee, or of coverage if a retiree, an employee or retiree shall be entitled, subject to the requirements of the commission, to convert his catastrophic illness coverage to a nongroup type of policy.

The commission may promulgate rules and regulations implementing and maintaining the provisions of this section, and such rules and regulations shall not be subject to the provisions of chapter thirty A.