Billow: METs Measured Lung Function; Adding the Impairments Needed More Evidence

A functional test can help explain a lung impairment without becoming a second injured body part. In Billow v. The Boys and Girls Aid Society of Los Angeles County, No. ADJ6508173 (WCAB Jan. 16, 2026), the Appeals Board corrected an award that listed metabolic equivalents, or METs, separately from the worker’s lungs. It also returned the permanent-disability calculation for further medical development. The panel accepted important medical and vocational reasoning, while requiring a fuller explanation of whether the medical evidence justified adding the different impairments.

The award involved several systems after a toxic exposure

Amber Billow worked as a wraparound counselor and sustained a toxic-exposure injury on August 23, 2007. The challenged award found injury to her lungs, upper digestive system in the form of gastroesophageal reflux disease (GERD), psyche and sleep, and separately listed METs. The judge awarded 100 percent permanent disability based on medical and vocational evidence and applied a 15 percent increase to the permanent-disability rate under Labor Code section 4658(d).

The employer challenged several different steps: The pulmonary rating by analogy, addition of impairments instead of the Combined Values Chart, the treatment of nonindustrial factors, the vocational conclusion and the separate METs finding. Those objections required separate answers. The Board’s eventual decision preserved the lung, digestive, psychiatric and sleep injury findings and further medical treatment, while deferring permanent disability and related issues.

The pulmonary analogy had a medical explanation

The earlier pulmonary assessment assigned 26 percent whole-person impairment. Dr. Bruce Gillis later explained that a rating by analogy using a coronary-heart-disease table within the AMA Guides better reflected Billow’s pulmonary limitations. He described how her respiratory disorder and reduced exercise capacity limited standing, walking and climbing, along with environmental restrictions. The opinion traces changing test results and weight over time rather than treating one number as the entire medical history.

Under the framework discussed in Billow, a physician proposing an alternative Guides rating needs to give the conventional rating, explain why it fails to reflect the worker’s functional limitations accurately and support the alternative with medical reasoning. The Board found Dr. Gillis’s explanation substantial evidence for rebutting the scheduled rating. His alternative 74 percent assessment concerned pulmonary impairment by analogy; the measurement did not establish another injured anatomical region.

That distinction matters to the calculation. Choosing a better-supported way to measure one impairment and deciding how multiple impairments interact are separate steps. Acceptance of the pulmonary analogy did not supply the missing explanation for adding every system’s impairment.

Vocational evidence connected the restrictions to work

Vocational expert Paul Broadus described a limited weekly pattern: Billow could shop, run errands and walk her dog on about two good days, while functioning poorly on other days. His report addressed difficulty standing, cooking, doing household chores and sustaining concentration. He concluded that she was unable to compete for suitable gainful employment or benefit from vocational rehabilitation.

The Board found that assessment persuasive because it rested on Dr. Gillis’s medical evidence and the described limits on daily activities. Broadus also addressed the nonindustrial conditions rather than ignoring them: His report said that he excluded fibromyalgia from the vocational analysis and explained why the internal-medicine restrictions independently prevented work. The medical foundation and the connection to sustained work were central to the Board’s reasoning.

Adding the impairments required more than an assertion of synergy

The remaining problem was how to combine the pulmonary, digestive, psychiatric and sleep impairments. Dr. Gillis had supported addition and described the systems as having a synergistic effect. The Board nevertheless found his discussion incomplete under Vigil v. County of Kern (2024) 89 Cal.Comp.Cases 686, 692 (WCAB en banc), which had issued after the trial judge’s decision.

As Billow explains, the medical evidence must identify each impairment’s effect on activities of daily living. It must then establish either an absence of overlap or explain how overlapping effects increase or amplify the impact on those activities. Naming several conditions or calling their relationship synergistic leaves that work unfinished. The Board required further development on those actual functional relationships before fixing permanent disability.

METs measured capacity rather than a separate injury

The Board addressed the METs finding directly. One MET represents energy used at rest. Lower MET levels can show greater limitations in physical activity and reduced capacity for work or daily tasks. In this pulmonary case, the measurement helped evaluate what the lung impairment meant for functioning.

The rating still had to be attributable to a condition or anatomical region. The Board explained that METs are neither a disease process nor a body part and could not be rated as pulmonary disability separate from the lungs. Its substituted findings removed the separate METs injury while retaining the lung injury. The error was in classifying the measure as another injury, not in using functional evidence to assess the pulmonary condition.

The employer retained its apportionment burden

The employer also attacked the absence of apportionment for the lung and digestive impairments in light of nonindustrial fibromyalgia. Dr. Gillis had recognized nonindustrial fibromyalgia but found no basis to apportion the lung and digestive disability to it. The Board required a reasoned medical explanation of what caused permanent disability and placed the burden of proving apportionment on the employer. It found that the employer had not met that burden on the record before it and could not shift it to Billow by characterizing her evidence as insufficient.

The opinion also set out the Board’s en banc Nunes rule separating medical apportionment from vocational assessment. Vocational evidence can explain work consequences and help identify disability attributable to particular systems. It cannot replace otherwise valid medical apportionment with a vocational expert’s own causal allocation. Because permanent disability required further development, the Board deferred apportionment as well.

The final disability award remained to be determined

The substituted findings preserved the identified lung, GERD, psychiatric and sleep injuries and an award of further medical treatment. They deferred permanent disability, apportionment and attorney fees. The employer’s request to strike Dr. Gillis’s reports was denied. The trial judge’s reconsideration report had recommended amending the 15 percent rate-increase finding. The Board deferred that question because the underlying permanent-disability issue was being deferred.

This is a WCAB panel application of the cited rating and evidentiary authorities to Billow’s record. Its practical value is the separation of the diagnosis, the functional measurement, the medical rating method, the interaction among impairments and the ultimate benefit award. Our guide to reading a METs entry in a pulmonary report focuses on the report-reading task. For a review of a disputed calculation, bring the complete medical reports, deposition testimony, vocational analysis and rating worksheet to our workers’ compensation team.