7.2.4.5 Apportionment

• Jurisdiction: Arizona

. When an employee’s earning capacity is affected by disabilities other than those resulting from an industrial accident, apportionment is necessary before a permanent disability award may be made. The manner in which this is done depends upon when the other conditions became disabling.

If the employee’s other disabilities preexisted his or her industrial accident, then “the percentage of disability for a subsequent injury [the industrial injury] shall be determined by computing the percentage of the entire disability and deducting therefrom the percentage of the previous disability as it existed at the time of the subsequent injury.’’^[46] If, however, the employee’s other disabilities developed only after the industrial accident, then they must be disregarded completely.^[47]

Of course, if the employee’s industrial accident aggravates a preexisting condition, so that the subsequent disability is a combination of both the preexisting condition and the impairment attributable to the industrial accident, no apportionment is available and the carrier or self-insured employer at the time of the accident is liable for the entire resulting disability.^[48]

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^[46]A.R.S. § 23-1044 (E). See...