Section 3. Work relief employes, as herein defined, are hereby declared to be employes of work relief employers for all purposes of the act to which this is a supplement. Any work relief employer who shall desire to be relieved of this liability to such work relief employe shall pay into the State Treasury the amounts provided in section four of this act. Payments to the State Treasurer of such amounts shall relieve the work relief employer of all further obligation for compensation to the work relief employe, or his dependents, and from obligation to carry insurance for such compensation, and shall exclude such liability from policies of insurance covering other types of employment.