                               No. 87-383
               IN THE SUPREME COURT OF THE STATE OF MONTANA
                                   1988


REX REACH,
                Claimant/Appellant,
       -vs-
MONTANA DEPARTMENT OF HIGHWAYS,
                Employer,
and
STATE COMPENSATION INSURANCE FUND,
                Defendants and Respondents.




APPEAL FROM:    The Workers' Compensation Court,
                The Honorable Timothy Reardon, LTudge presiding.

COUNSEL OF RECORD:
       For Appellant:
                Allen L. McAlear, Rozeman, Montana

       For Respondent:
                Nancy Butler, Helena, Montana



                                   Submitted on Briefs: February 4, 1988
                                      Decided:   March 31, 1988




                                   Clerk
Mr. Justice Fred J. Weber delivered the Opinion of the Court.



     Mr. Beach filed a petition in the Workers' Compensation
Court to obtain compensation in addition to that which the
State Compensation Fund had agreed to pay under the occupa-
tional deafness statutes, Title 39, Chapter 71, Part 8, MCA.
The court determined that Mr. Beach was not entitled to
additional compensation.    We affirm. Mr. Beach raises one
issue on appeal:
     Did the Workers' Compensation Court properly calculate
the compensation for occupational deafness?
      The parties have stipulated to most of the facts of this
case.    Mr. Beach worked for the Montana Highway Department
from 1978 to 1985.    In his job he operated a diesel mowing
machine and was in the proximity of noisy heavy trucks and
equipment. He suffered a loss of hearing as a result. In
1986 he received an audiogram test result which forms a basis
for the computation of disability.     The State Compensation
Insurance Fund (State Fund) has paid for a 90.9% hearing
impairment in the left ear, for 36.36 weeks at $146.50 per
week or $5,326.74.
     Mr. Beach contends that the Workers' Compensation Court
improperly construed the applicable statutes.   Those statutes
read as follows:

     39-71-805,     Determining percent of hearing loss.
     (1) The percent of hearing loss, for purposes of
     the determination of compensation claims for occu-
     pational deafness, 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, approved by nationally recognized
     authorities in this field, shall be used for mea-
     suring hearing loss.     If the losses of hearing
average 25 decibels or less in the three frequen-
cies, as measured under IS0 Standard 1964, such
losses of hearing shall not then constitute any
compensable hearing disability.     If the losses of
hearing average 92 decibels or more in the three
frequencies, as measured under IS0 Standard 1964,
then the same shall constitute and be total or 100%
compensable hearing loss.
     (2) In measuring hearing impairment, the
lowest measured losses in each of the three fre-
quencies shall be added together and divided by
three to determine the average decibel loss. For
every decibel of loss exceeding 25 decibels, an
allowance of 1 4 % shall be made up to the maximum of
loo%, which is reached at 92 decibels.
     (3) 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 impair-
ment in the poorer ear and the sum of the two
divided by six.       The final percentage shall be
representative of the binaural hearing impairment.
     (4) Before determining the percentage of
hearing impairment, in order to allow for the
average amount of hearing loss from nonoccupational
causes found in the population at any given age,
there shall be deducted from the total average
decibel loss one-half decibel for each year of the
employee's age over 40 at the time of last exposure
to industrial noise.
     (5) No consideration shall be given to the
question of whether or not the ability of an em-
ployee to understand speech is improved by the use
of a hearing aid.
39-71-808. Compensation for occupational deafness.
(1 Subiect to the limitations herein contained,
there shall be payable:
     (a) for total occupational deafness of one
ear, 40 weeks of compensation;
     (b) for total occupational deafness of both
ears, 200 weeks of compensation; and
     (c) for partial occupational deafness, compen-
sation shall bear such relation to that named
herein as disabilities bear to the maximum disabil-
ities herein provided.
Due to the complexity of the statute, we will set forth in
this  opinion   the  necessary  computations, which    are
substantially the same as those in the lower court's findings
of fact and conclusions of law.

Step one: Average Decibel Loss.
     The first step in computing percentage of hearing loss
is explained in subsections (1) and (2).      The court must
calculate the average in decibels of the thresholds of hear-
ing for each ear for the frequencies of 500, 1,000, and 2,000
cycles per second. This is the average decibel loss. Sub-
section (1) also explains that if the average is 25 decibels
or less, then such hearing loss is not compensable. If the
average is 92 decibels or more then the loss is total or 100%
compensable.   The statute, therefore, clearly establishes a
range within which the average decibel loss must fall to be
compensable.
     Subsection (2) specifically explains the procedure for
calculating average decibel loss. The lowest measured losses
in each of the three frequencies, as measured by an audio-
gram, are added together and divided by three. The following
table reflects the computation of this first step in calcula-
tion of percent of hearing loss, in Mr. Reach's case:

                                                      Average
                                               Total Decibel
Frequency      500
               -         1000      2000      Decibels    Loss

Right ear        5         35        50          90       30
Left ear        85        110       110         305      101..6

Step two: Age Factor.
      The last sentence of subsection (2) explains how these
averages are translated into percentage of hearing impair-
ment.    Subsection ( 4 ) , however, must first be considered.
This subsection requires a deduction of one-half decibel for
each year of age over 40 at the time of last exposure to
industrial noise. In Mr. Beach's case, the last exposure was
at age 72; therefore, we must deduct one-half decibel for 32
years or 16 decibels from the "total average decibel loss."
Mr. Beach contends that "total average decibel loss'' refers
to subsection (3) which explains how to compute the binaural
percentage of hearing impairment.    He argues that the 16
decibel age factor must be subtracted when calculating the
binaural percentage.     Mr. Beach's interpretation is not
consistent mathematically. He asks us to subtract the result
in subsection (4) in the computation of subsection (3), but
to do so we would have to deduct a sum expressed in decibels
from a sum expressed in percentages.           Additionally,
$ 39-71-808, MCA, allows compensation for hearing loss in
only one ear. Were we to adopt Mr. Beach's argument, the age
factor would be deducted for a worker with hearing loss in
both ears but not for a worker with loss in only one ear.
Such a result does not comport with the obvious purpose of
the age factor deduction -- to avoid compensating a worker
for losses due to age rather than work conditions. Rather,
we conclude that the age factor must be deducted from the
average decibel loss for each ear, determined previously in
step one. That calculation is illustrated as follows:

            Right ear: 30 - 16 = 14 decibels.
            Left ear: 101.6 - 16 = 85.6 decibels.

Step three: Monaural Hearing Impairment Percentage.
     Now, we return to the second sentence of subsection (2)
which explains how to translate the hearing loss from deci-
bels to percentages.
     For every decibel of loss exceeding 25 decibels, an
     allowance of I + %shall be made up to the maximum of
     loo%, which is reached at 92 decibels.
We observe that after taking into account the age factor from
the previous calculation, the right ear had an average hear-
ing loss of 14 decibels.       Under the standard set forth in
subsection ( I ) , this hearing loss is not compensable because
it is less than 25 decibels. The percentage of occupational
impairment to the right ear is 0%. To determine the percent-
age of impairment in the left ear, we must multiply 13%
(.015) times every decibel of loss exceeding 25 decibels.



The left ear, then, has a 90.9% hearing impairment.
     Mr. Beach argues that once the excess over 25 decibels
is multiplied by It%, the 25 decibels should be added back
into the equation. Again, to follow his interpretation, we
would have to add a sum expressed in decibels to a sum ex-
pressed in percentages. That would result in a mathematical-
ly incorrect computation.    The Workers' Compensation Court
provided an explanation why the statute utilizes a 25 decibel
floor of compensability.

          The statutory language I .  . .such losses of
     hearing shall not then constitute any compensable
     hearing disability.' is clear. The logic behind a
     25 average decibel loss being noncompensable, as
     well as why a 92 average decibel loss is total, is
     found in Guides - - Evaluation of Permanent
                       to the
     Impairment, American Medical ~ s s o c G t i o n , pp.
     103-4, (1971).
             In order to evaluate the hearing impair-
          ment, it must be recognized that the range
          impairment is not nearly as wide as the audio-
          metric range of human hearing.     Audiometric
          zero, which is presumably the average normal
          threshold level, is not the point at which
         impairment begins.    If the average hearing
         level at 500, 1,000 and 2,000 Hz is 25 dB (15
         dB, ASA-1951) or less, usually no impairment
         exists in the ability to hear everyday speech
         under everyday conditions.      At the other
         extreme, however, if the average hearing level
         at 500, 1,000 and 2,000 Hz is over 92.7 dB
         (81.7 dB, ASA-1951), the impairment for hear-
         ing everyday speech should be considered
         total.   For every detail that the estimated
         hearing level for speech exceeds 25 dB (15 dB,
         ASA-1951), 1.5% of monaural impairment is
         allowed up to a maximum of 100%. This maximum
         is reached at 91.7 dB (81.7 dB, ASA-1951).
Step four: Binaural Hearing ~mpairmentPercentage.
     The last step, found in subsection (3), requires a
translation of monaural hearing loss percentages into a
binaural hearing loss percentage. We compute this percentage
as follows:

              (0% x 5)       + .909   -   .I515
                         6

Therefore, the binaural hearing impairment is 15.15%.
     We now must calculate the compensation due Mr. Beach,
pursuant to 5 39-71-808(1), MCA:

         (1) Subject to the limitations herein con-
    tained, there shall be payable:
         (a) for total occupational deafness of one
    ear, 40 weeks of compensation;
         (b) for total occupational deafness of both
    ears, 200 weeks of compensation; and
         (c) for partial occupational deafness, com-
    pensation shall bear such relation to that named
    herein as disabilities bear to the maximum disabil-
    ities herein provided.
    Mr. Beach's right ear sustained no compensable impair-
ment and his left ear was not 100% impaired; therefore, the
compensations listed in subsections (a) and (b) for maximum
disabilities do not apply.   Subsection (c) applies as Mr.
Beach has suffered partial occupational deafness.       For monau-
ral disability, he would receive 9 0 . 9 % of 4 0 weeks or 3 6 . 3 6
weeks of compensation for his left ear and none for his right
ear. For binaural disability, he would receive 15.15% of 2 0 0
weeks or 3 0 . 3 0 weeks of compensation. The Workers' Compensa-
tion Court awarded Mr. Beach 3 6 . 3 6 weeks as the greater
amount of compensation to which he was entitled.         F e hold
                                                          J
that the Workers' Compensation Court properly calculated
monaural and binaural hearing impairments. We also hold that
the court properly exercised its discretion in awarding Mr.
Beach the larger sum to which he was entitled under the
statute. Affirmed.



We Concur:
    n   r
        ,



5   Chief Justice
