Authorities as the decision cited them, with how this panel applied each one.
Labor Code section 5705; Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604 (Appeals Board en banc); Pullman Kellogg v. Workers' Comp. Appeals Bd. (1980) 26 Cal.3d 450
Employer bears burden of proof to show apportionment of permanent disability based on reasonable medical probability.
Employer must demonstrate legal basis for apportionment with substantial evidence.
From the decision · page 5While the employee holds the burden of proof regarding the approximate percentage of
permanent disability directly caused by the industrial injury, the employer holds the burden of
proof to show apportionment of permanent disability. (Lab. Code, § 5705; see also Escobedo v.
Marshalls (2005) 70 Cal.Comp.Cases 604, 613 (Appeals Board en banc), Pullman Kellogg v.
Workers' Comp. Appeals Bd. (Normand) (1980) 26 Cal.3d 450 [45 Cal.Comp.Cases 170].) To
meet this burden, the employer "must demonstrate that, based upon reasonable medical
probability, there is a legal basis for apportionment." (Gay v. Workers' Comp. Appeals Bd. (1979)
96 Cal.App.3d 555, 564 [44 Cal.Comp.Cases 817]; see also Escobedo, supra, 70 Cal.Comp.Cases
at p. 620.)
Labor Code sections 4663(a), 4663(c)
Apportionment of permanent disability shall be based on causation; physician reports must include apportionment determination with reasons if unable to apportion.
Physicians must address apportionment in permanent impairment reports.
From the decision · page 5"Apportionment of permanent disability shall be based on causation." (Lab. Code, § 4663(a).) Physicians are required to address apportionment when evaluating permanent
impairment. (Lab. Code, § 4663(b)-(c).) Section 4663(c) provides in pertinent part as follows:
Labor Code section 4664(a)
Employer liable only for percentage of permanent disability directly caused by industrial injury.
Determination of employer liability based on causation and apportionment.
From the decision · page 6Section 4664(a) separately states that the "employer shall only be liable for the percentage of
permanent disability directly caused by the injury arising out of and occurring in the course of
employment." (Lab. Code, § 4664(a).)
Hegglin v. Workmen's Comp. Appeals Bd. (1971) 4 Cal.3d 162
Medical reports are not substantial evidence if based on erroneous facts, inadequate histories, or incorrect legal theories.
Medical opinion based on inadequate history is not substantial evidence for apportionment.
From the decision · page 7"Medical reports and opinions are not substantial evidence if they are known to be
erroneous, or if they are based on facts no longer germane, on inadequate medical histories and
examinations, or on incorrect legal theories. Medical opinion also fails to support the Board's
findings if it is based on surmise, speculation, conjecture or guess." (Hegglin v. Workmen's Comp.
Appeals Bd. (1971) 4 Cal.3d 162, 169 [36 Cal.Comp.Cases 93].) Dr. Angerman apportioned to
the 2016 non-industrial motor vehicle accident without review of the complete medical records
pertaining to applicant's treatment and condition in relation to that accident. Pursuant to Hegglin,
a medical opinion based on an inadequate history is not substantial evidence.
Brodie v. Workers' Comp. Appeals Bd. (2007) 40 Cal.4th 1313; Kopping v. Workers' Comp. Appeals Bd. (2006) 142 Cal.App.4th 1099
Determining apportionment requires looking at current disability and parceling out causative sources; subtraction method applies only if prior award and overlap proven.
Apportionment between industrial injuries requires proof of prior award and overlap; not applicable here as new and further disability claim.
From the decision · page 10Defendant also argues for apportionment per section 4664 based on the 26% permanent
disability for the lumbar spine due to the July 16, 2012 injury already stipulated to in the 2015
award. Determining apportionment requires looking "at the current disability and parcel[ing] out
its causative sources--nonindustrial, prior industrial, current industrial--and decide the amount
directly caused by the current industrial source." (Brodie v. Workers' Comp. Appeals Bd.
(2007) 40 Cal.4th 1313, 1328 [72 Cal.Comp.Cases 565], emphasis added.) Per Brodie and section
4664, it is proper to apportion between two industrial injuries using the subtraction method where
the defendant proves the existence of a prior permanent disability award and that there is overlap
between the prior disability and the current disability. (See also Kopping, supra.) The 2015 award
was for the same injury for which applicant has shown new and further disability. This is therefore
not a "subsequent industrial injury" under section 4664(b). (Lab. Code, § 4664(b), emphasis
added.) Applicant is entitled to a new permanent disability award reflecting the total level of
disability resulting from the July 16, 2012 injury and defendant is entitled to credit for amounts
previously paid as permanent disability. (Shedelbower, supra.) This is precisely what the F&A
reflects.