Section 102C. Two or more stock or two or more mutual companies authorized to transact business under either the first or the fifth clause of section forty-seven may issue a single policy of insurance against loss or damage to property by radioactive contamination, whether or not such policy also includes insurance against loss or damage to property by one or more other perils proper to insure against in this commonwealth or insurance against loss of use or occupancy, on which each company shall be severally liable for a specified percentage of any loss or claim. Such a policy may be executed on behalf of the companies by a duly authorized person and need not be countersigned by a resident agent of more than one of such companies in the commonwealth.

No such policy shall be issued or delivered until a copy of the form thereof has been on file for thirty days with the commissioner, unless before the expiration of such thirty days he shall have approved the form of the policy in writing; nor if the commissioner notifies the company in writing within said thirty days that in his opinion the form of the policy does not comply with the laws of the commonwealth, specifying his reasons therefor; provided, that such action shall be subject to review by the supreme judicial court; nor unless the corporate name of each company is affixed thereto; nor unless it contains in substance:—

(1) A provision plainly specifying the percentage of any loss or claim for which each company shall be liable.

(2) A provision that any notice, sworn statement or proof of loss which may be required by the provisions of said policy may be rendered, made or given to any one of the companies or to the agent named in the policy as the duly authorized agent of the companies, and that such notice, sworn statement or proof of loss so rendered, made or given shall be valid and binding as to all of such companies.

(3) A provision that, in any action or suit under the policy, service of process may be made on any one of such companies and that such service shall be deemed valid and binding service upon all of such companies.

The provisions of sections seventy-six, eighty, eighty-one and eighty-three shall apply to policies issued under this section by mutual companies except as hereinafter provided.

The person insured under such a policy issued by mutual companies shall be deemed to be a member of each company while the policy is in force and entitled to one vote at the meetings of each company.

The notice, endorsement and statement required by said sections seventy-six, eighty and eighty-one, respectively, shall be in such form and in such place on the policy as the commissioner may prescribe.

The dividends under said section eighty and the contingent mutual liability, if any, of the insured under said sections eighty-one and eighty-three shall be computed or based, for each company, on such proportion of the total premium for the policy as the amount insured by such company bears to the total amount insured under the policy.

The notice to policyholders required by said section eighty shall be sent by each such company to the insured.

Nothing in this section shall be construed as affecting, except as provided herein, any provision of law relative to the rights, powers, duties and liabilities of mutual fire companies and persons insured thereby.