BRADLEY EATON, Employee/Appellant, v. 3M CO. and SEDGWICK CLAIMS MANAGEMENT, Employer-Insurer/Respondents, and HEALTHPARTNERS, ST. PAUL RADIOLOGY MIDWEST PHYSICIANS, and MINN. LUNG CTR., Intervenors.

The employee appeals the compensation judge’s determination that the employee failed to prove that he suffered occupational asthma due to his work with the employer.  Because substantial evidence supports the judge’s findings, we affirm.

Bradley Eaton, the employee, has worked as a chemical engineer for 3M, the employer, since 1986.  The employee claimed that his work exposed him to chemicals which caused him to suffer shortness of breath, coughing attacks, intermittent headaches, and heart palpitations.  Relying on material safety data sheets which describe various chemicals to which he was exposed as upper respiratory irritants, he claimed to be entitled to workers’ compensation benefits for an alleged occupational asthma condition.  The employee’s medical history also includes longstanding non-work-related conditions of obstructive sleep apnea, allergic rhinitis, seasonal allergies, food allergies, and obesity.

On May 15, 2014, the employee saw Dr. Robert Campbell at the 3M Medical Clinic, complaining of a rapid heart rate, cough and headaches, which the employee attributed to exposure to chemical vapors at work associated with a high-temperature extruder machine.  Dr. Campbell recommended that the employee keep a log of exposures and symptoms and return in one month.  On June 17, 2014, the employee returned to Dr. Campbell, who ordered a pulmonary function test (PFT).  The PFT was performed on June 24, 2014, and showed an FEV1/FVC ratio of 81 percent, within the normal range.  Dr. Campbell reviewed the PFT results on July 22, 2014.  He noted that they showed no obstructive changes but showed possible restrictive lung disease which he thought might relate in part to the employee’s obesity.

When the employee’s symptoms worsened at work, Dr. Campbell considered it possible that the symptoms were due to working in a specific building at the 3M complex where the extruder was located.  The employer transferred the employee to another building in October 2014.  However, the employee testified that while his symptoms subsequently improved, they did not entirely resolve.

On December 15, 2014, the employee saw pulmonologist Dr. Patrick Wright for a consultation at the request of Dr. Campbell.  Dr. Wright ordered another PFT, which again showed an FEV1/FVC ratio within the normal range.  Dr. Wright diagnosed the employee with restrictive lung disease and obstructive sleep apnea.^[1]  Dr. Wright ordered a CT scan of the chest which was negative.

By March 30, 2015, following treatment efforts, Dr. Wright noted that the bronchodilators typically used to treat asthma had failed to reduce the employee’s symptoms.  PFT results on May 5, 2015, showed an FEV1/FVC ratio of 73 percent, suggestive of mild obstruction. Dr. Wright referred the employee to the Mayo Clinic for a pulmonary consultation with Clayton Cowl, M.D.

On December 10, 2015, Dr. Cowl conducted an examination, reviewed the material safety data sheets provided by the employee, and administered a PFT which showed an overall FEV1/FVC ratio of 71.2 percent, suggesting a mild obstruction.  Bronchodilator administration improved the employee’s FEV1.

In his December 24, 2015, report and subsequent correspondence to Dr. Wright, Dr. Cowl diagnosed the employee with occupational asthma and restricted him from working in areas which triggered respiratory symptoms.  Dr. Cowl also recommended that the employee lose weight and take medication to minimize the effect of acid reflux.  After receiving Dr. Cowl’s consultation report, Dr. Wright opined that the employee had occupational asthma and rated his permanent partial disability (PPD) as either 28 or 33 percent under Minn. R.  5223.0560, subp. 3(10) or 3(11).^[2]

The employer and insurer sought the medical opinion of Patrick Arndt, M.D., an associate professor at the University of Minnesota Division of Pulmonary, Allergy, and Critical Care Medicine.  Dr. Arndt reviewed multiple medical records, took a history from the employee, reviewed the material data safety sheets regarding the chemicals to which the employee claimed exposure, and examined the employee.  Dr. Arndt wrote a narrative report on July 19, 2017 followed by a supplemental report on August 29, 2017.  He diagnosed the employee with a longstanding history of seasonal allergies to ragweed, pine pollen and hay, with symptoms of headache, coughing, tachycardia and shortness of breath.  He noted that the symptoms recorded in the employee’s symptoms log often occurred before the employee went to work, including while he was at home showering.  In addition, he found it significant that the employee’s symptoms failed to improve while using frontline asthma therapy, explaining that this would make it less likely that the employee had asthma.  Dr. Arndt also noted that evidence of airflow obstruction was lacking.  Accordingly, he concluded that the employee did not have occupational asthma.  He did not consider the employee permanently partially disabled, as his FEVI/FVC ratios were normal, he had a normal CT scan, and he had not undergone a methacholine challenge test to confirm asthma.  Although Dr. Arndt concluded that the employee did not have work-related asthma, he recommended that he be restricted from working in the building with the extruder, as the transfer to another building appeared to help to alleviate the employee’s anxiety that his job was causing his symptoms.

The employee filed a claim petition alleging occupational asthma and seeking PPD benefits and payment of medical expenses, including expenses related to the use of a CPAP machine which had been prescribed for obstructive sleep apnea.  The matter was heard before a compensation judge on November 9 and November 21, 2018.  The compensation judge found that the employee had not met his burden of proof that he had sustained a work-related injury in the nature of occupational asthma on or about March 30, 2014, as a result of his work with the employer.  He found the opinions of both Drs. Cowl and Wright unpersuasive and adopted the opinion of Dr. Arndt, who had opined that the record did not support a diagnosis of occupational asthma.  The employee appeals.

On appeal, the Workers’ Compensation Court of Appeals must determine whether “the findings of fact and order [are] clearly erroneous and unsupported by substantial evidence in view of the entire record as submitted.”  Minn. Stat. § 176.421, subd. 1(3).  Substantial evidence supports the findings if, in the context of the entire record, “they are supported by evidence that a reasonable mind might accept as adequate.”  Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 59, 37 W.C.D. 235, 239 (Minn. 1984).  Where evidence conflicts or more than one inference may reasonably be drawn from the evidence, the findings are to be affirmed.  Id. at 60, 37 W.C.D. at 240.  Similarly, findings of fact should not be disturbed, even though the reviewing court might disagree with them, “unless they are clearly erroneous in the sense that they are manifestly contrary to the weight of evidence or not reasonably supported by the evidence as a whole.”  Northern States Power Co. v. Lyon Food Prods., Inc., 304 Minn. 196, 201, 229 N.W.2d 521, 524 (1975).

A decision which rests upon the application of a statute or rule to essentially undisputed facts generally involves a question of law which the Workers’ Compensation Court of Appeals may consider de novo.  Krovchuk v. Koch Oil Refinery, 48 W.C.D. 607, 608 (W.C.C.A. 1993), summarily aff’d (Minn. June 3, 1993).

The compensation judge concluded that the employee failed to meet his burden of proof that he had sustained occupational asthma.  In his memorandum, he noted as significant that multiple PFT results demonstrated a near normal range of lung function, that there had been no consistent improvement with frontline asthma medication, and that examinations demonstrated no wheezing during flareups.

On appeal, the employee argues that the evidence supports a different conclusion than that reached by the compensation judge.  He argues that the judge should have found that the employee has occupational asthma, as his job duties had exposed him to chemicals known to cause upper respiratory injury.  That the exposure actually caused an occupational asthma, he argues, is demonstrated by a paucity of symptoms when he was not working and an aggravation of his symptoms when at work.  He argues that the testing performed at the Mayo Clinic proved he had developed work-related asthma, noting that all the medical experts, including Dr. Arndt, considered the PFT findings to be suggestive of a possible underlying asthma or bronchiolitis.  The employee also contends that the compensation judge erred in failing to award PPD benefits, citing Taylor v. City of Fridley, 73 W.C.D. 895 (W.C.C.A. 2013) and Eisenmenger v. Raven Indus., slip op. (W.C.C.A. Mar. 15, 2000), cases in which a methacholine challenge test was held not to be a necessary prerequisite to a PPD rating where an employee’s condition was such that the testing would be medically dangerous.  The employee requests that this court reverse the findings denying the employee’s occupational disease and PPD claims, and substitute new findings awarding PPD benefits consistent with the opinions of the employee’s experts.^[3]

On appeal, however, the question before this court is not whether the evidence might support different findings, but whether the judge’s decision was “clearly erroneous and unsupported by substantial evidence in view of the entire record as submitted.”  Minn. Stat. § 176.421, subd. 1.

We conclude that the compensation judge’s findings are adequately supported by the record.  The compensation judge reasonably relied on several factors.  The employee had a history of allergies, sinusitis, and obstructive sleep apnea.  The symptoms he attributed to the alleged occupational asthma condition included heart palpitations, headaches, a cough and shortness of breath, none of which are uniquely attributable to that condition.  The employee’s PFT results were read as normal or near normal and his lungs were clear and without wheezing or crackling.  The standard frontline medicinal treatment for occupational asthma symptoms was attempted but had no effect on him.  Finally, the employee’s symptom logs showed that many of his symptoms would occur in the morning prior to going to work and without exposure to chemicals.  We note that the record is unclear regarding the actual extent of the employee’s work exposure to the claimed irritants.

Various physicians noted other possible explanations for the employee’s symptoms which were not addressed during the course of treatment.  Although he diagnosed the employee with occupational asthma, Dr. Cowl also recommended that the employee lose weight and take medication to minimize the effects of gastric reflux disease.  Dr. Wright acknowledged that many of the employee’s symptoms could be the result of his sleep apnea condition, allergic rhinitis, obesity, or deconditioning.  He also acknowledged that his initial pulmonary diagnosis was mild restrictive lung disease, which did not indicate any airflow obstruction due to asthma.

Finally, the judge’s finding was supported by the medical opinion of Dr. Arndt.  It is well established that a compensation judge’s choice among conflicting expert opinions must be upheld unless the opinion lacked adequate factual foundation.  Nord v. City of Cook, 360 N.W.2d 337, 342-43 (Minn. 1985).  The opinion need only be based on “enough facts to form a reasonable opinion that is not based on speculation or conjecture.”  Gianotti v. Indep. Sch. Dist. 152, 889 N.W.2d 796, 802 (Minn. 2017).  Whether an expert’s opinion rests on adequate foundation “is a decision within the discretion of the trial judge, subject to review for abuse of discretion.”  Id.  Dr. Arndt’s opinion rested on sufficient foundation and there is no evidence that his opinion was based on conjecture or speculation.  The employee presents no compelling argument why the judge’s choice of expert should not be affirmed.

Because the judge’s finding that the employee did not develop occupational asthma as result of his work at 3M is supported by substantial evidence, we need not address the appeal from the denial of the employee’s associated claim for PPD benefits.