Any condition or impairment of health of any member of a volunteer fire department caused by any disease of the respiratory system shall be held and presumed to be an occupational disease unless the contrary be made to appear in rebuttal by satisfactory proof; providing
Any present member who did not undergo a medical examination upon entering said volunteer fire service, may undergo such examination within 180 days after the effective date of this act and in the event such examination does not disclose the presence of such disease or diseases, he shall thereafter be entitled to the benefits of this act.
N.J.S. § 34:15-43.2