(a) Any employer carrying on any exempted or excepted employment may at any time waive the exemptions or exceptions as to any employee or all employees engaged in the employment as the employer may elect by giving notice of waiver of the exemptions or exceptions as provided in subsection (b) of this section.
(b) Notice of waiver of exclusion or exemption referred to in subsection (a) of this section shall be given in accordance with the following provisions:
(1) Every employer who waives the exclusion or exemption shall post, and keep posted, in and about the employer's place of business typewritten or printed notices to that effect in accordance with a form to be prescribed by the Workers' Compensation Commission, and the employer shall file a duplicate of the notice with the commission.
(2) The notice shall be given at least thirty (30) days prior to any injury. However, if the injury occurs less than thirty (30) days after the date of employment, the notice, if given at the time of employment, shall be sufficient notice.