E.L. Yeager v. Workers' Comp. Appeals Bd. (Gatten) (2006) 145 Cal.App.4th 922
Substantial medical evidence must be based on reasonable medical probability, accurate history, examination, and reasoning supporting conclusions.
The WCJ's reliance on Dr. Baum's opinion was found to lack adequate clinical history and reasoning, thus not substantial medical evidence.
From the decision · page 9reasoning to support the expert conclusions reached. (E.L. Yeager v. Workers' Comp. Appeals Bd.
(Gatten) (2006) 145 Cal.App.4th 922, 928 [71 Cal.Comp.Cases 1687]; Escobedo v. Marshalls
(2005) 70 Cal.Comp.Cases 604 (Appeals Board en banc).) "A medical report predicated upon an
incorrect legal theory and devoid of relevant factual basis, as well as a medical opinion extended
beyond the range of the physician's expertise, cannot rise to a higher level than its own inadequate
premises." (Zemke v. Workmen's Comp. Appeals Bd. (1968) 68 Cal.2d 794 [69 Cal.Rptr. 88, 441
P.2d 928, 33 Cal.Comp.Cases 358, 363].) "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 [36 Cal.Comp.Cases at 93, 97]
Whether a physician's opinion constitutes substantial evidence "must be determined by the material
facts upon which his opinion was based and by the reasons given for his opinion." (Ibid.)
Bethlehem Steel Co. v. Industrial Acc. Com. (1943) 21 Cal.2d 742
In communicable disease cases, industrial causation can be established by showing it is more likely the disease was acquired at work or that employment exposed the employee to a special risk beyond the general population.
The Appeals Board ordered further development of the medical record to determine if applicant's COVID-19 infection was more likely acquired at work or from other sources.
From the decision · page 9Substantial evidence of industrial causation must be based on reasonable medical
probability--it is not required to prove causation to a "scientific certainty." (See McAllister v.
Workmen's Comp. App. Bd. (1968) 69 Cal. 2d 408, [71 Cal.Rptr. 697, 445 P.2d 313, 33
Cal.Comp.Cases 660]; Rosas v. Workers' Compensation Appeals Board (1993) 16 Cal.App.4th
1692 [20 Cal.Rptr.2d 778, 58 Cal.Comp.Cases 313, 319].) In cases where an applicant's injury is
caused by a communicable disease, the essential questions of when and where applicant contracted
the disease may be unanswerable with any certainty. In those circumstances, the employee can
establish industrial causation by demonstrating that it is more likely applicant acquired the disease
at work or that the employment subjected the employee to a special risk of exposure in excess of
the general population. (Bethlehem Steel Co. v. Industrial Acc. Com. (1943) 21 Cal.2d 742 [135
P.2d 153, 8 Cal.Comp.Cases 61].)