(a) As used in this Code section, the term:

(1) "Harmful noise" means sound in employment capable of producing occupational loss of hearing as defined in paragraph (2) of this subsection. Sound of an intensity of less than 90 decibels, A scale, shall be deemed incapable of producing occupational loss of hearing as defined in this Code section.

(2) "Occupational loss of hearing" means a permanent sensorineural loss of hearing in both ears caused by prolonged exposure to harmful noise in employment.

(b) Compensation based on 66 2/3 percent of average weekly wages, subject to limitations of Code Section 34-9-261, shall be payable for loss of hearing caused by harmful noise, subject to the following rules which shall be applicable in determining eligibility, amount, and period during which compensation shall be payable:

(1) In the evaluation of occupational hearing loss, only the hearing levels at the frequencies of 500, 1,000, and 2,000 cycles per second shall be considered. Hearing losses for frequencies below 500 and above 2,000 cycles per second are not to be considered as constituting compensable hearing disability. No consideration shall be given to the question of whether or not the ability of an employee to understand speech is improved by the use of a hearing aid. The board may order the employer to provide the employee with an original hearing aid if it will materially improve the employee's ability to hear;

(2) The percentage of hearing loss shall be calculated as the average, in decibels, of the thresholds of hearing for the frequencies of 500, 1,000, and 2,000 cycles per second. Pure tone air conduction audiometric instruments, properly calibrated according to accepted national standards such as American Standards Association, Inc. (ASA), International Standards Organization (ISO), or American National Standards Institute, Inc. (ANSI), shall be used for measuring hearing loss. If more than one audiogram is taken, the audiogram having the lowest threshold will be used to calculate occupational hearing loss. If the losses of hearing average 15 decibels (26 db if ANSI or ISO) or less in the three frequencies, such losses of hearing shall not constitute any compensable hearing disability. If the losses of hearing average 82 decibels (93 db if ANSI or ISO) or more in the three frequencies, then the same shall constitute and be total or 100 percent compensable hearing loss. In measuring hearing impairment, the lowest measured losses in each of the three frequencies shall be added together and divided by three to determine the average decibel loss. For each decibel of loss exceeding 15 decibels (26 db if ANSI or ISO) an allowance of 1 1/2 percent shall be made up to the maximum of 100 percent which is reached at 82 decibels (93 db if ANSI or ISO). In determining the binaural percentage of loss, the percentage of impairment in the better ear shall be multiplied by five. The resulting figure shall be added to the percentage of impairment in the poorer ear, and the sum of the two divided by six. The final percentage shall represent the binaural hearing impairment; (3) There shall be payable for total occupational loss of hearing 150 weeks of compensation and for partial occupational loss of hearing such proportion of these periods of payment as such partial loss bears to the total loss;

(4) Except in instances of preexisting loss of hearing due to disease, trauma, or congenital deafness in one ear, no compensation shall be payable under this Code section unless prolonged exposure to harmful noise in employment has caused loss of hearing in both ears as hereinafter provided;

(5) No compensation benefits shall be payable for temporary total or temporary partial disability under this Code section; and there shall be no award for tinnitus or a psychogenic hearing loss;

(6) The regular use of employer provided protective devices capable of preventing loss of hearing from the particular harmful noise where the employee works shall constitute removal from exposure to such particular harmful noise. No compensation benefits shall be payable for occupational loss of hearing caused by harmful noise if the employee fails to regularly utilize the employer provided protection device or devices which are capable of preventing loss of hearing from the particular harmful noise where the employee works;

(7) The employer liable for the compensation in this Code section shall be the employer in whose employment the employee was last exposed to harmful noise in Georgia during a period of 90 working days or parts thereof; and an exposure during a period of less than 90 working days or parts thereof shall be held not to be an injurious exposure; provided, however, that, in the event an insurance carrier has been on the risk for a period of time during which an employee has been injuriously exposed to harmful noise and if after such insurance carrier goes off the risk said employee has been further exposed to harmful noise, although not exposed for 90 working days or parts thereof, so as to constitute an injurious exposure, such carrier shall, nevertheless, be liable;

(8) An employer shall become liable for the entire occupational hearing loss to which his employment has contributed; but, if previous deafness is established by a hearing test or other competent evidence, whether or not the employee was exposed to harmful noise within six months preceding such test, the employer shall not be liable for previous loss so established, nor shall he be liable for any loss for which compensation has previously been paid or awarded. The employer shall be liable only for the difference between the percentage of occupational hearing loss determined as of the date of disability and the percentage of loss established by preemployment and audiometric examinations excluding, in any event, hearing losses arising from nonoccupational causes.

(c) No claim for compensation for occupational hearing loss shall be filed until six months have elapsed since exposure to harmful noise with the last employer. The last day of such exposure shall be the date of disability.