Upon the termination of the former Workers’ Compensation Commission, the Coal-Workers’ Pneumoconiosis Fund shall close to new subscribers. All claims payment obligations, including indemnity benefits, medical benefits, administrative, and all other expenses necessary for the administration and defense of claims, where the date of last exposure is on or before December 31, 2005, without regard to the date the claim is filed, shall be an obligation of the Coal-Workers’ Pneumonoconiosis Fund.