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IN THE SUPREME COURT OF THE STATE OF IDAHO

Docket No. 49171

RICHARD NELSON,

 Claimant-Respondent,

v.

CITY OF POCATELLO, 

Self-Insured Employer,

 Defendant-Appellant.

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Boise, February 2022 Term

Opinion filed: April 29, 2022

Melanie Gagnepain, Clerk 

Appeal from the Industrial Commission of the State of Idaho.

The decision of the Industrial Commission is affirmed.

Bowen & Bailey, LLP, Boise, for Appellant. Michael McPeek argued.

Racine Olson, PLLP, Pocatello, for Respondent. Rachel Miller argued.

 _______________________________________________

MOELLER, Justice.

Following a 21-year career as a firefighter with the City of Pocatello (“the City”), Richard 

Nelson was diagnosed with leukemia. Nelson brought a workers’ compensation claim against the 

City. The Industrial Commission determined that the City failed to rebut a statutory presumption 

of causation with substantial and competent evidence. The City appeals the Industrial 

Commission’s factual findings and conclusions of law. It argues there was substantial evidence to 

rebut the presumption that Nelson’s cancer was caused by his employment. The City also argues 

that Idaho Code section 72-438(14)(b), which is the source of the presumption the Industrial 

Commission applied, unconstitutionally discriminates between the employers of firefighters who 

have cancer and the employers of other employees who claim to have contracted an occupational 

disease. For the following reasons, we affirm the Industrial Commission. 
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I. FACTUAL AND PROCEDURAL BACKGROUND

Richard Nelson was a firefighter for 21 years, working for the City from 1993 to 2014. In 

his career as a firefighter, Nelson was promoted through a series of positions, becoming a First 

Class Firefighter in 1995, a Driver/Operator in 2005, and Captain in the Fire Prevention and Public 

Education Division in 2011. He was actively involved in fire prevention and investigation for 18 

years, from 1993 to 2011, and retired as a firefighter in 2014. 

In November 2018, Nelson was diagnosed with early-stage chronic lymphocytic leukemia

(“CLL”). He notified his employer the same month and timely submitted a workers’ compensation 

claim for his medical benefits. The CLL was not revealed during any initial employment medical 

screening examinations with the City of Pocatello, nor was the diagnosis made more than ten years 

following Nelson’s promotion to Captain or his retirement as a firefighter. Additionally, Nelson 

and his family have not habitually used tobacco products for ten or more years prior to Nelson’s 

CLL diagnosis. Altogether, these stipulated facts led the Industrial Commission and parties to 

agree that Nelson’s CLL diagnosis qualifies for the presumption in Idaho Code section 72-

438(14)(b) that “[the] disease shall be presumed to be proximately caused by [his] . . . employment 

as a firefighter.” I.C. § 72-438(14)(b). 

The City sought to rebut this statutory presumption with the report and testimony of Robert 

E. Burdick, M.D. Dr. Burdick’s report discussed studies and statistics concerning the association 

between CLL and firefighting. He explained: 

As these 6 summary studies show, time after time, no matter how the 

medical literature is massaged, the data just does not support a premise that 

firefighting significantly increases the risk of CLL on a more probable than not 

basis. It is also my opinion that in those few studies in the older literature where an 

increase was seen, the increase was an aberration usually observed when too few 

patients are included in the analysis.

Based on this analysis, Dr. Burdick concluded that “the absence in the medical literature of a 

medically probable link between firefighting and CLL,” meant “a physician cannot conclude with 

medical probability that Mr. Nelson’s CLL is causally related, on a more probable than not basis, 

to toxins he may have been exposed to during his employment for the city of Pocatello as a 

firefighter.”

While there was no evidentiary hearing in this case, the parties deposed Dr. Burdick on 

March 8, 2021. In his deposition, Dr. Burdick explained that CLL is an overgrowth of lymphocytes 
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within the bone marrow. Nelson’s CLL diagnosis was discovered early enough to place it in the 

lowest “Rai classification”;

1 thus, it did not require immediate treatment. On cross-examination, 

Dr. Burdick conceded that no one could truly say what caused Nelson’s CLL:

Q. All right. Let me read from your report so I get it correct and I don’t misstate it.

I believe you say that a physician cannot conclude with medical probability that 

Mr. Nelson’s CLL is causally related on a more probable basis than not to toxins 

that he may have been exposed to during his employment with the City of Pocatello 

as a firefighter.

Is it fair to say that, no one can say what caused Mr. Nelson’s CLL?

A. That’s accurate.

Q. All right. So you cannot say with a reasonable degree of medical certainty what 

is the cause of [Nelson’s CLL]; is that accurate?

A. That’s accurate.

Dr. Burdick also testified concerning his report, medical study statistics connecting cancer to 

potential causes, and medical research indicating radon as a general cause of CLL.

The Industrial Commission concluded that the City “failed to produce substantial 

affirmative evidence” to rebut the statutory presumption of causation because it “failed to produce 

affirmative medical evidence that [Nelson’s] cancer was caused by something other than his 

employment.” The Industrial Commission also concluded that Idaho’s firefighter presumption law, 

enacted in 2016, was unambiguous; it plainly requires the Commission “to presume, unless there 

is ‘substantial evidence to the contrary’, [sic] that a claimant’s disease was proximately caused by 

his employment as a firefighter.” This, the Commission concluded, the City failed to do. 

Following the Industrial Commission’s decision, the City filed a motion to make the 

Commission’s findings and conclusions immediately appealable to the Idaho Supreme Court. 

Nelson did not object to the motion, and the Commission granted it. The City then timely appealed 

to this Court.

II. STANDARD OF REVIEW

The standard of review for appeals from the Industrial Commission is two-fold: (1) while 

this Court freely reviews the Commission’s legal conclusions, (2) we “will not disturb the 

 1 The “Rai classification” or “Rai Staging” is a staging system for determining the spread of cancer. It is useful in 

guiding treatment, determining prognosis, and ascertaining the risks for patients with chronic lymphocytic leukemia 

(CLL).
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Commission’s factual findings so long as they are supported by substantial and competent 

evidence.” Page v. McCain Foods, Inc., 155 Idaho 755, 760, 316 P.3d 671, 676 (2014).

“Constitutional issues and the construction and application of legislative acts are pure 

questions of law over which this Court exercises free review.” Struhs v. Prot. Techs., Inc., 133 

Idaho 715, 718, 992 P.2d 164, 167 (1999). See also Politte v. Dep’t of Transp., 126 Idaho 270, 

272, 882 P.2d 437, 439 (1994). “It is generally presumed that legislative acts are constitutional, 

that the state legislature has acted within its constitutional powers, and any doubt concerning 

interpretation of a statute is to be resolved in favor of that which will render the statute 

constitutional.” Olsen v. J.A. Freeman Co., 117 Idaho 706, 709, 791 P.2d 1285, 1288 (1990). The 

party asserting a statute’s unconstitutionality “bears the burden of showing [the statute’s] invalidity 

and must overcome a strong presumption of validity.” Id. This Court exercises its judicial power 

“to declare legislative action invalid upon constitutional grounds . . . only in clear cases.” 

Gomersall v. St. Luke’s Reg’l Med. Ctr., Ltd., 168 Idaho 308, 314, 483 P.3d 365, 371 (2021). 

III. ANALYSIS

The key issue before the Industrial Commission was whether the City produced substantial 

evidence to rebut the presumption that Nelson’s cancer was caused by his employment as a 

firefighter. The Industrial Commission determined that the City failed to rebut that presumption

pursuant to Idaho Code sections 72-438(b) and (c). On appeal, the City raises questions concerning

the statute’s constitutionality for the first time, maintaining, “the Idaho Supreme Court is the 

proper forum for contesting the constitutionality of a statutory provision of the Idaho Workers’ 

Compensation law.” (citing Tupper v. State Farm Ins., 131 Idaho 724, 729, 963 P.2d 1161, 1166 

(1998)). Generally, this Court does not address constitutional claims made for the first time on 

appeal. Gordon v. Hedrick, 159 Idaho 604, 612, 364 P.3d 951, 959 (2015); Tupper v. State Farm 

Ins., 131 Idaho 724, 729, 963 P.2d 1161, 1166 (1998). However, “because the [Industrial] 

Commission does not have jurisdiction to address [] constitutional challenges,” a party may 

properly raise such issues before this Court on appeal. See Tupper, 131 Idaho at 729, 963 P.2d at 

1166. Accordingly, we will consider the City’s argument on the statute’s constitutionality.

A. Idaho Code sections 72-438(14)(b) and (c) are constitutional.

The City first argues on appeal that “the presumption of causation under 72-438(l4)(b) in 

firefighter cancer cases, and the standard in Idaho Code § 72-438(14)(c) for overcoming the 
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presumption, both deny [it] equal protection of the law under art. l § 2 of the Idaho Constitution 

and the Fourteenth Amendment to the United States Constitution.” The City contends that these 

statutory provisions carve out a classification for the employers of firefighters with cancers 

enumerated in the workers’ compensation laws, which is distinct from the employers of employees 

contracting other occupational diseases under Idaho law. While the City concedes this 

classification does not qualify for strict-scrutiny analysis under either state or federal equal

protection analysis, it argues the statutory classification qualifies for the Idaho Supreme Court’s 

“means-focus test.” Nelson counters that the means-focus test is inapplicable here because the 

statutory classification created by Idaho Code sections 72-438(l4)(b) and (c) can only qualify for 

rational basis review, and it does not violate either the U.S. or Idaho Constitutions. We agree with 

Nelson’s analysis. 

When addressing equal protection claims, we apply a three-step analysis: “(1) identifying 

the classification under attack; (2) identifying the level of scrutiny under which the classification 

will be examined; and (3) determining whether the applicable standard has been satisfied.” 

Gomersall v. St. Luke’s Reg’l Med. Ctr., Ltd., 168 Idaho 308, 318, 483 P.3d 365, 375 (2021) (citing 

Coghlan v. Beta Theta Pi Fraternity, 133 Idaho 388, 395, 987 P.2d 300, 307 (1999)). If the claims 

arise under the U.S. Constitution, we implement one of “three levels of scrutiny: strict scrutiny, 

intermediate scrutiny, [or] rational basis.” Id. This Court employs similar levels of scrutiny when 

analyzing equal protection challenges under the Idaho Constitution; however, intermediate 

scrutiny is replaced by the means-focus test. Id. Thus, when addressing the constitutionality of a 

statute under the Idaho Constitution, we apply the following tests:

Where the classification is based on a suspect classification or involves a 

fundamental right we have employed the “strict scrutiny” test. Where “the 

discriminatory character of a challenged statutory classification is apparent on its 

face and where there is also a patent indication of a lack of relationship between the

classification and the declared purpose of the statute,” the “means-focus” test is 

applicable. In other cases the “rational basis” test is employed.

Olsen v. J.A. Freeman Co., 117 Idaho 706, 710, 791 P.2d 1285, 1289 (1990) (quoting 

Johnson v. Sunshine Mining Co., 106 Idaho 866, 870, 684 P.2d 268, 271 (1984)). 

The parties agree that strict scrutiny does not apply under the United States or Idaho 

constitutions because neither a suspect class nor a fundamental right are involved in this case. 

However, the parties dispute whether Idaho’s “means-focus” test or a rational basis test applies, 
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and whether the appropriate test is satisfied. While the City alleges a violation of the Fourteenth 

Amendment’s rational basis standard, it does so without any accompanying arguments. There is 

no other mention of the U.S. Constitution or federal case law in that portion of the City’s briefing 

and analysis. Thus, the City’s challenge is grounded solely on the Idaho Constitution. We will 

address each step of our equal protection analysis in turn. 

1. The classification under attack. 

In 2016, the Legislature passed H.B. 554 to amend the workers’ compensation laws 

regarding occupational diseases in an effort “to provide a presumption of proximate causation 

between specified diseases and employment as a firefighter,” as well as to provide compensation 

“payable for disability or death resulting from certain firefighter occupational diseases.”2 H.B. 

554, S.L. 2016, ch. 276, § 2. The statute at issue in this case states in full: 

Compensation shall be payable for disability or death of an employee resulting from 

the following occupational diseases: . . . 

(14) Firefighter occupational diseases:

(a) As used in this subsection, “firefighter” means an employee whose primary 

duty is that of extinguishing or investigating fires as part of a fire district, fire 

department or fire brigade.

(b) If a firefighter is diagnosed with one (1) or more of the following diseases 

after the period of employment indicated in subparagraphs (i) through (xi) of this 

paragraph, and the disease was not revealed during an initial employment medical 

screening examination that was performed according to such standards and 

conditions as may be established at the sole discretion of the governing board 

having authority over a given fire district, fire department, or fire brigade, then 

the disease shall be presumed to be proximately caused by the firefighter’s 

employment as a firefighter: . . . 

 2 In the aftermath of the September 11, 2001, attacks in New York City and Washington, D.C., many states took 

legislative steps to recognize the difficulties firefighters and first responders face in proving work-related cancers by 

creating presumptions of causation in their workers’ compensation statutes. See Anthony J. Macauley, Recent 

Developments in Workers’ Compensation Law, 39 TORT TRIAL & INS. PRAC. L.J. 779, 781–82 (2004) (noting a rising 

national trend among the states to increase workers’ compensation coverage for safety officers and volunteers 

following 9/11, including the creation of statutory presumptions); Lawrence D. Tarr & Salvatore Lupica, Workers’ 

Compensation, 39 U. RICH. L. REV. 475, 509 (2004) (“Catastrophic events, such as natural disasters and the tragic and 

unnerving events of September 11, 2001, have already catalyzed debate and change as seen in last year’s legislation 

attempting to clarify murky issues as to coverage for some of those whose work puts them on the frontline.”). As of 

the date of this opinion, 49 states, including Idaho, have adopted statutory presumptions of occupational diseases for 

firefighters. IAFF Presumptive Health Initiative, State Presumptive Disability Chart (Apr. 12, 2021), 

https://www.iaff.org/wp-content/uploads/Presumptive_Disability_Chart_as_of_4-12-2021.pdf (last visited April 28, 

2022).
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(vi) Leukemia after five (5) years;

. . . 

(c) The presumption created in this subsection may be overcome by substantial 

evidence to the contrary. If the presumption is overcome by substantial evidence, 

then the firefighter or the beneficiaries must prove that the firefighter’s disease 

was caused by his or her duties of employment.

(d) The presumption created in this subsection shall not preclude a firefighter 

from demonstrating a causal connection between employment and disease or 

injury by a preponderance of evidence before the Idaho industrial commission.

(e) The presumption created in this subsection shall not apply to any specified 

disease diagnosed more than ten (10) years following the last date on which the 

firefighter actually worked as a firefighter as defined in paragraph (a) of this 

subsection. Nor shall the presumption apply if a firefighter or a firefighter’s 

cohabitant has regularly and habitually used tobacco products for ten (10) or more 

years prior to the diagnosis.

I.C. § 72-438(14). 

Specifically at issue in this equal protection challenge are subsections (14)(b) and (c), 

which permit employers of firefighters with one of the enumerated cancers to rebut the statutory 

presumption of causation by submitting “substantial evidence to the contrary.” I.C. § 72-

438(14)(c). Nelson, having been diagnosed with CLL, based his claim on section 72-

438(14)(b)(vi), which mentions leukemia. Thus, the classification here is based on occupation,

employment, and disease. The classification creates a distinction under Idaho law between the 

employers of firefighters with cancers enumerated in the workers’ compensation laws, and 

employers of employees engaged in different work who contract occupational diseases. 

2. The means-focus test does not apply to the statute in question. 

With the parties in agreement that strict scrutiny is inapplicable to this case, either Idaho’s 

means-focus test or the rational basis test must apply to the alleged unconstitutional discrimination. 

The City contends the classification here requires the means-focus test, but argues that the statute 

fails to satisfy either the means-focus or rational basis tests. 

The means-focus test is applicable if two conditions are met: (1) “[w]here the 

discriminatory character of a challenged statutory classification is apparent on its face and [(2)] 

where there is also a patent indication of a lack of relationship between the classification and the 

declared purpose of the statute[.]” Gomersall, 168 Idaho at 318, 483 P.3d at 375 (quoting Olsen, 

117 Idaho at 710, 791 P.2d at 1289). Thus, “[t]he means-focus equal protection analysis requires 
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a determination of whether different treatment is accorded to persons on the basis of criteria wholly 

unrelated to the objective of the statute.” State v. Beam, 115 Idaho 208, 212, 766 P.2d 678, 682 

(1988) (citations and internal quotations omitted). 

We conclude that neither prong of the means-focus test has been met. Addressing the first

prong, there is no apparent discriminatory character or motive attributable to this classification. 

The distinction between classes under Idaho Code section 72-438(14)(c) is employers of 

firefighters with cancer and the employers of other employees with occupational diseases. While 

the employers of firefighters are subject to different evidentiary standards, the statutory

presumption is not intended to punish such employers; rather, the presumption protects firefighters 

as an occupational class at greater risk of contracting cancers due to the nature of their work. 

Neither the text of section 72-438, its legislative history, nor common sense suggests that the 

presumption was created to unlawfully discriminate against those who employ firefighters. 

Second, there is no “lack of a relationship between the classification and the declared 

purpose of the statute.” The legislative history behind Idaho Code section 72-438(14)(c) is both 

thorough and clear. The Statement of Purpose provides: 

This bill addresses the nearly impossible burden of proving occupational diseases 

associated with firefighting within the workers compensation system. Research has 

established that firefighters are significantly more likely to develop certain types of 

cancer than the general population. Under current law, the burden of proof for these 

known occupational diseases is nearly impossible to overcome as exposures are 

chronic, occur over long periods of time, and are uncertain regarding specific toxins 

and carcinogens present at any given structure fire. This bill would change existing 

workers compensation law so that it would be presumed that such diseases were 

occupationally related unless medical evidence showed otherwise.

Statement of Purpose, RS24515C, H.B. 554 (2016). As part of the appellate record, Nelson also 

included a two-hour recording from the 2016 Legislature’s debates and materials concerning the 

adoption of this firefighter presumption. The content of this hearing included the following 

testimony: 

• Firefighters are first responders that cannot know what environments and toxins 

they will be exposed to when responding to a fire. They can be exposed to any 

number of hazardous materials in addition to smoke and fumes. 

• “It is estimated that between 2% and 8% of all cancers are attributable to 

occupational exposures,” and firefighters are “routinely exposed to mixtures of 

chemical substances” contained in fire smoke and building debris. Medical studies 
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of groups of firefighters, while varied, indicate a statistically significant increased 

risk of firefighters to develop the bill’s listed cancers, with the exception of breast 

cancer.

• “Fire smoke is a complex mixture of cancer-causing chemicals from combustion of 

all the various products in modern fires.” Studies have revealed that firefighters are 

often exposed to many chemicals that are known carcinogens, including, but not 

limited to, asbestos, benzene, formaldehyde, diesel-engine exhaust, and soot. 

Cancers develop over time and from multiple exposures. Different cancers have 

different latency periods, and, thus, have the different time periods assigned to the 

bill’s enumerated cancers. The challenges of (1) the lack of exposure assessments 

and (2) firefighters’ general better health than the rest of the population leads to 

possible underestimation of true risk in statistical and medical studies. As a result, 

indications from studies that firefighters have a potential increased risk of cancer 

may still be underestimating their true risk of developing or dying from cancer. As 

of 2016, over 30 states have passed legislation to create a presumption of causation 

of cancer from firefighting. 

• The Professional Firefighters of Idaho vetted the bill’s policy with the Industrial 

Commission.

• Richard Owens, an attorney representing injured workers, explained that without 

this legislation, an injured firefighter would have to gather detailed information 

about the number of times the firefighter was exposed to the chemical or toxin that 

caused his cancer. This includes proving what specific toxin the firefighter was 

exposed to, where they were, how many times exposure occurred to that particular 

toxin, and when each exposure occurred over the years of firefighting. Then the 

worker must also prove that causation, i.e., that those particular toxin exposures 

caused his cancer. Owens stated: “That doesn’t mean that these cases are difficult; 

it means that these cases are impossible.” 

Idaho Legislature Audio/Video Archive, House Commerce & Human Resources Committee 

Meeting (March 3, 2016, 1:30 PM), complete audio download available at 

https://insession.idaho.gov/IIS/2016/House/Committee/Commerce%20&%20Human%20Resour

ces/160303_hcom_0130PM-Meeting.mp4 (last visited April 28, 2022).

This legislative background manifests a clear “relationship between the classification and 

the declared purpose of the statute.” Gomersall, 168 Idaho at 318, 483 P.3d at 375 (quoting Olsen, 

117 Idaho at 710, 791 P.2d at 1289). Creating this classification of employers of firefighters with 

cancer was a part of the Legislature’s effort to create new evidentiary burdens and procedures that 

protect firefighters from the difficult hurdles of proving the causation of their cancer diagnoses. 

Importantly, the statute creates a rebuttable presumption. Employers of firefighters—whether 

public or private—can shift the evidentiary burden back to a claimant upon showing substantial 
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evidence that a claimant’s cancer was not caused by his occupation. Altogether, these statutory 

classifications and criteria are both nondiscriminatory and wholly related to the statute’s objective. 

3. The rational basis test applies here. 

Rational basis is the applicable standard where the means-focus and strict scrutiny tests do 

not apply. Gomersall, 168 Idaho at 319, 483 P.3d at 376; Olsen, 117 Idaho at 710, 791 P.2d at 

1289. In applying the rational basis test, it makes no difference whether the classification is 

challenged under the U.S. Constitution or the Idaho Constitution, for the test is the same: “Under 

either the Fourteenth Amendment or the Idaho Constitution, a classification will survive rational 

basis analysis if the classification is rationally related to a legitimate governmental purpose.” 

Gomersall, 168 Idaho at 319, 483 P.3d at 376 (quoting Meisner v. Potlatch Corp., 131 Idaho 258, 

262, 954 P.2d 676, 680 (1998)). “This Court will not evaluate the fairness or efficacy of the statute 

that is being challenged.” Id. (quoting McLean v. Maverik Country Stores, Inc., 142 Idaho 810, 

814, 135 P.3d 756, 760 (2006). Furthermore, the rational basis standard is “generally employ[ed] 

. . . when examining statutes concerning economic interests.” Id.

Here, the statutory presumption created by section 72-438(14)(b) addresses economic and 

societal policy interests as it concerns employment and occupation for a class of employees 

determined to face unique risks: firefighters. Such concerns have traditionally been reviewed under 

a rational basis analysis. See id. Likewise, because neither the means-focus nor strict scrutiny 

standards apply to the classification at issue, we must apply the rational basis test and next

determine whether the test is satisfied. See id. 

4. The protections afforded firefighters in Idaho Code sections 72-438(14)(b) and (c) 

satisfy the rational basis test. 

Rational basis review only requires us to determine whether “there is any conceivable state 

of facts which will support [the statutory provision],” without judging “the wisdom or fairness of 

the legislation being challenged.” Gomersall, 168 Idaho at 319, 483 P.3d at 376 (internal 

quotations omitted); Coghlan, 133 Idaho at 396, 987 P.2d at 308. Thus, “[u]nder the rational basis 

test, a classification will pass scrutiny if it is rationally related to a legitimate governmental 

purpose.” Gomersall, 168 Idaho at 320, 483 P.3d at 377 (citing Meisner, 131 Idaho at 262, 954 

P.2d at 680). 
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Here, the challenged legislation is a statute that protects firefighters who develop cancer 

by providing a presumption of causation for the enumerated occupational disease, making it easier

for them to qualify for workers’ compensation benefits. The 2016 Legislature amended Idaho’s 

occupational-disease laws after hearing considerable evidence that firefighters have an increased 

risk in contracting certain types of cancer and a difficult burden to prove causation for workers’ 

compensation under the then-existing laws. This evidence consisted of: medical studies indicating 

a correlation between firefighting and cancer; testimony regarding the complex chemicals and 

known carcinogens firefighters are regularly and often unknowingly exposed to as they respond to 

fires in wild, rural, urban, and industrial settings; testimony from a physician and an epidemiologist 

on the medical studies and statistics; the prior status of the workers’ compensation laws and 

difficulties firefighters face in trying to prove causation for occupational-disease compensation; 

and the unlikelihood that the legislation would raise workers’ compensation costs. We conclude 

that there is ample evidence and facts in the legislative record to support the legislation’s purpose

and will not second-guess the Legislature’s policy choices. 

Therefore, we conclude that the rational basis test applies and is satisfied by the facts of 

this case. Accordingly, Idaho Code section 72-438(14)(c) does not violate the City of Pocatello’s 

equal-protection rights.

B. The Industrial Commission correctly determined that the City failed to present 

“substantial evidence to the contrary” to rebut the presumption that Nelson’s cancer 

was caused by his occupation as a firefighter.

The parties do not dispute that Nelson’s CLL qualifies for a rebuttable presumption of 

causation as enumerated in Idaho Code section 72-438(14)(b). Instead, the parties argue whether 

the City presented substantial evidence to rebut the statutory presumption of causation. The City 

argues the “Commission misapplied the law to the facts in determining that [its] evidence was 

legally insufficient to satisfy the ‘substantial evidence to the contrary[’] standard,” while Nelson 

contends the City failed to present affirmative evidence that Nelson’s CLL had a non-occupational 

cause. The Industrial Commission concluded “substantial evidence to the contrary” requires more 

than just challenging the factual basis of the statutory presumption itself; rather, the employer must

present “affirmative medical evidence that . . . there is a non-work-related cause that is a substantial 

factor in causing the cancer.” We affirm the Commission’s conclusion.
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Idaho’s workers’ compensation laws contain numerous provisions governing 

compensation for occupational diseases. Applicable to this case is Idaho Code section 72-

438(14)(b), which states: 

If a firefighter is diagnosed with one (1) or more of the following diseases after the 

period of employment indicated in subparagraphs (i) through (xi) of this paragraph, 

and the disease was not revealed during an initial employment medical screening 

examination that was performed according to such standards and conditions as may 

be established at the sole discretion of the governing board having authority over a 

given fire district, fire department, or fire brigade, then the disease shall be 

presumed to be proximately caused by the firefighter’s employment as a firefighter.

Leukemia is one of the listed occupational diseases presumed to be caused “after five (5) years” 

of employment as a firefighter. I.C. § 72-438(14)(b)(vi). This statutory presumption can only apply 

where the specified disease is diagnosed within “ten (10) years following the last date on which 

the firefighter actually worked as a firefighter.” I.C. § 72-438(14)(e). The presumption may not 

apply where “a firefighter or a firefighter’s cohabitant has regularly and habitually used tobacco 

products for ten (10) or more years prior to the diagnosis.” Id. Idaho Code section 72-438(14)(c)

establishes an opportunity to rebut this presumption: “The presumption created in this subsection 

may be overcome by substantial evidence to the contrary. If the presumption is overcome by 

substantial evidence, then the firefighter or the beneficiaries must prove that the firefighter’s 

disease was caused by his or her duties of employment.” (Emphasis added.)

Like “substantial evidence,” “substantial evidence to the contrary” does not have to amount 

to a preponderance, but it must be “such relevant evidence as a reasonable mind might accept to 

support a conclusion[.]” Evans v. Hara’s, Inc., 123 Idaho 473, 478, 849 P.2d 934, 939 (1993); 

Seamans v. Maaco Auto Painting & Bodyworks, 128 Idaho 747, 753, 918 P.2d 1192, 1198 (1996).

The plain reading of “contrary” suggests that an employer must overcome the statutory 

presumption by presenting substantial evidence contradicting the presumption that an individual

claimant’s cancer was caused by his work as a firefighter. In other words, there must be affirmative 

evidence that the claimant’s cancer was caused by something other than the occupation of 

firefighting.

Such an application of Idaho Code section 72-438(14)(c) corresponds with this Court’s 

prior interpretations of “substantial evidence to the contrary.” While this Court has never 

interpreted Idaho Code section 72-438(14)(c), it has examined identical language to that at issue 
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here. For instance, Idaho Code section 72-228 provides a rebuttable presumption of causation in 

certain claims for workers’ compensation. It states: 

In any claim for compensation, where the employee has been killed, or is physically 

or mentally unable to testify, and where there is unrebutted prima facie evidence 

that indicates that the injury arose in the course of employment, it shall be 

presumed, in the absence of substantial evidence to the contrary, that the injury 

arose out of the employment and that sufficient notice of the accident causing the 

injury has been given.

I.C. § 72-228 (emphasis added). There are a few cases that have directly interpreted this 

“substantial evidence to the contrary” language. 

First, in Hatley v. Lewiston Grain Growers, Inc., the Court examined a statutory 

presumption that “in the absence of substantial evidence to the contrary, . . . the injury or death [of 

employee] was not occasioned by the employee’s intoxication . . . .” 97 Idaho 719, 722, 552 P.2d 

482, 485 (1976) (citing I.C. § 72-208 (1976) and I.C. § 72-228). The Hatley Court determined the 

workers’ compensation statutesrequired the “employer relying on the intoxication defense to come 

forth with substantial affirmative evidence showing that the employee was intoxicated at the time 

of death and also that the intoxication proximately resulted in the injury.” Id. An identical approach 

was followed in Evans v. Hara’s, Inc. There, the Court interpreted Idaho Code section 72-228’s 

“substantial evidence to the contrary” language as requiring an employer to “come forward with 

substantial affirmative evidence” that indicated “the accident did not arise out of the employment.” 

123 Idaho at 478, 849 P.2d at 939. Once established, the Court explained, “the burden shifts back 

to the employee to persuade the Commission that it did indeed arise out of the employment.” 

Likewise, in Politte v. Dept. of Transp., this Court reviewed the Commission’s application 

of the statutory presumption in Idaho Code section 72-228 as it concerned medical evidence. 126 

Idaho at 272, 882 P.2d at 439. In Politte, the claimant had suffered a stroke that left him partially 

paralyzed and “unable to testify” within the meaning of Idaho Code section 72-228. Id. at 271, 882 

P.2d at 438. The Commission found the claimant was entitled to the presumption that his stroke 

arose in the course of his employment. Id. The employer attempted to rebut this presumption with 

the following evidence: first, it presented credible testimony from the claimant’s supervisors that 

there was no causal connection between the claimant’s stroke and his work; second, the employer 

provided a letter from a cardiovascular surgeon who stated the claimant’s stroke had no relation to 

his employment and that there were other “risk factors” in his history, including hypertension, 
14

hypercholesterolemia, hypertriglyceridemia, and elevated blood sugar. Id. The Commission 

ultimately concluded that the supervisors, while credible, did not provide proof of a medical nature. 

The Commission also concluded that the surgeon’s letter failed to present substantial evidence to 

the contrary because the foundation for his opinion was unknown. Id.

On appeal, this Court affirmed the Commission’s order, determining that the employer 

failed to provide substantial and affirmative medical evidence contrary to the presumption that the 

claimant’s injury arose from his employment. Id. at 272–73, 882 P.2d at 439–40. Regarding the 

surgeon’s letter, the Court agreed that there was no foundation for the opinion. The Court 

explained: “There is no verification in the evidence presented to the Commission that the medical 

records contained in these exhibits were the medical records the surgeon received from the claims 

examiner. This raises serious questions concerning what records the surgeon used to arrive at the 

opinion contained in the letter.” Id. The Court also agreed with the Commission that testimony 

from the claimant’s supervisors was insufficient, for “[t]he causal relationship of an injury to the 

claimant’s employment must be supported by at least some medical proof.” Id. at 273, 882 P.2d 

437, 440 (emphasis added). 

While these cases vary somewhat in facts and circumstances, the Hatley interpretation has 

been consistently applied: “substantial evidence to the contrary” means “substantial affirmative 

evidence” contrary to the presumption. Politte, 126 Idaho at 272–73, 882 P.2d at 439–40; Evans, 

123 Idaho at 478, 849 P.2d at 939; Hatley, 97 Idaho at 722, 552 P.2d at 485. Politte further 

established that an employer must rebut the presumption of causation with medical proof. 126 

Idaho at 273, 882 P.2d 437, 440. Because the presumption here is that the claimant’s cancer was

caused by his employment as a firefighter, the employer would have to present substantial and

affirmative medical evidence that the claimant’s cancer was not caused by his employment.

Here, the City presented evidence from Dr. Burdick, an oncologist and medical expert who 

opined that Nelson’s cancer was not caused by firefighting. However, Dr. Burdick’s foundation 

for his report was solely based on evidence that firefighting, in general, does not significantly 

increase the risk of cancer on a more-probable-than-not basis. In other words, Dr. Burdick’s report 

sought to rebut the presumption not by showing an alternate cause for Nelson’s CLL, but by 

attacking the evidentiary foundation for the underlying the presumption contained in the statute. 

The report states: “time after time, no matter how the medical literature is massaged, the data just 
15

does not support a premise that firefighting significantly increases the risk of CLL on a more 

probable than not basis.” (Emphasis added.) While Dr. Burdick gives one potential cause of CLL—

radon in the Pocatello area—he does not offer any affirmative evidence suggesting that Nelson

was exposed to radon or that his CLL was actually caused by radon. Indeed, the doctor conceded 

in both his report and deposition that there is no way to know what actually caused Nelson’s CLL, 

be it ambient exposure to radon, exposures to toxins while firefighting, or otherwise:

Q. [Counsel for the Industrial Commission]: Is it fair to say that, no one can say 

what caused Mr. Nelson’s CLL?

A. [Dr. Nelson]: That’s accurate.

Q. All right. So you cannot say with a reasonable degree of medical certainty what 

is the cause of [Nelson’s CLL]; is that accurate?

A. That’s accurate.

Even if Dr. Burdick disagrees with the Legislature’s conclusion that medical studies 

support a causal connection between firefighting and cancer, an expert witness cannot unilaterally 

overcome a legislatively enacted presumption simply by offering a contrary opinion. To do so 

would essentially permit Dr. Burdick, through his testimony, to strike down a legislative enactment

on evidentiary grounds. Instead, Dr. Burdick should have directed his research and testimony 

towards Nelson’s CLL and offered proof of an alternative cause for it. Ultimately, the City’s 

evidence appears to only challenge the statutory presumption itself, rather than rebut the 

presumption that Nelson’s cancer was caused by his employment. Although Dr. Burdick’s report 

generally disputes the validity of the legislatively enacted premise that firefighting increases the 

risk of developing cancer, he failed to establish that Nelson’s cancer was caused by something 

other than firefighting. Such a course must be rejected by this Court, for we do not judge “the 

wisdom or efficacy” of a challenged statute. Gomersall, 168 Idaho at 319, 483 P.3d at 376. As this 

Court has long held: “[t]he wisdom of such legislation is with the Legislature, and not with the 

court.” Smallwood v. Jeter, 42 Idaho 169, 244 P. 149, 155 (1926). Importantly, Dr. Burdick’s 

deposition illustrates the exact evidentiary difficulty the Legislature was concerned with: that 

firefighters could almost never prove in court that their cancer was caused by their employment.

As noted in the International Association of Fire Fighters’ amicus brief, most jurisdictions 

have rejected challenges to their rebuttable presumptions enacted to protect firefighters and other 

first responders. This includes rejections to constitutional challenges on equal protection grounds. 
16

See, e.g., Moes v. City of St. Paul, 402 N.W.2d 520, 525 (Minn. 1987). Likewise, other state 

appellate courts have long rejected similar attempts by employers to disprove the underlying 

premise of a legislatively created presumption, rather than rebutting the presumption as it applies 

to a specific claimant. See, e.g., Adamson v. Municipality of Anchorage, 333 P.3d 5, 20 (Alaska 

2014) (“rebuttal evidence must be personal to the claimant, not evidence attempting to undermine 

the legislature’s determination that the enumerated diseases are occupational diseases of 

firefighters.”); City of Frederick v. Shankle, 785 A.2d 749, 755 (Md. 2001) (“What is not permitted 

is for an expert to deny or contradict the presumption altogether, simply because the expert does 

not agree with the basis for it.”); Robertson v. N. Dakota Workers Comp. Bureau, 616 N.W.2d 

844, 855 (N.D. 2000) (“ . . . the effect of the presumption would be defeated if it could be rebutted 

by expert medical opinion generally denying the validity of the legislatively enacted premise that 

work stress causes heart problems.”); Cunningham v. City of Manchester Fire Dep’t, 525 A.2d 

714, 720 (N.H. 1987) (“[The doctor’s] testimony went no further than to question the wisdom of 

the legislature, without producing evidence of non-work-related causes of Young’s 

arteriosclerosis. This type of testimony is insufficient to rebut the presumption.”); Sperbeck v. 

Dep’t of Indus., Lab. & Hum. Rels., 174 N.W.2d 546, 549 (Wis. 1970) (“Evidence which only 

attacks the rationale of the statute, without exposing the cause of death of a particular claimant, 

does nothing more than question the wisdom of the legislature.”).

It is clear from the plain reading of the statute that the Legislature intended to create a 

rebuttable presumption that firefighters diagnosed with certain types of cancer qualify for workers’ 

compensation benefits as a result of their contracting a disease proximately caused by their 

employment. Even in the light of conflicting medical evidence and studies, the Idaho Legislature 

resolved the issue in favor of Idaho’s firefighters. By adopting this statutory presumption, the 

Idaho Legislature recognized the unique dangers facing these crucial first responders and the 

importance of firefighters in our communities. As noted frequently throughout the legislative 

materials, firefighters risk consistent exposure to unknown toxins and hazards, which, the 

Legislature reasonably concluded, could result in the development of certain cancers—diseases 

that can rarely be pinned down to a specific cause. Therefore, they determined that the burden 

should no longer be on the firefighters to prove their occupation caused the cancer, but on the 

employer to prove substantial evidence to the contrary. Thus, Idaho Code section 72-438(14)(c), 
17

much like Idaho Code section 72-228, requires an employer to present substantial affirmative 

medical proof supporting a non-work-related cause. This the City failed to do. 

The City cites Est. of Aikele v. City of Blackfoot to contend that “the Court should apply a 

different standard to the determination of ‘substantial evidence to the contrary’ for purposes of 

Idaho Code § 72-438(14)(c) than the interpretation it gave to the presumption at issue in Evans.” 

Aikele is a workers’ compensation case that dealt with a firefighter failing to prove the causation 

of his lung cancer, and it precedes the current legislation at issue. Est. of Aikele v. City of Blackfoot, 

160 Idaho 903, 906–07, 382 P.3d 352, 355–56 (2016). In that case, the Industrial Commission 

denied a firefighter workers’ compensation benefits based on disputed factual findings between 

the medical experts, including a meta-analysis of 32 studies on cancer risk in firefighters. Id. at 

907, 909–11, 382 P.3d at 356, 358–60. The Court ultimately upheld the Commission’s factual 

findings as reasonable and supported by the record. Id. at 911, 382 P.3d at 360. The Court also 

determined: “The meta-analysis, which concluded no similar association exists between 

firefighting and lung cancer, is the most comprehensive body of information available in the 

record. Thus, the Commission’s consideration of a risk analysis was appropriate under the 

circumstances.” Id. at 909, 382 P.3d at 358. 

The City argues this language and holding from Aikele requires the Court to conclude that 

“testimony of a physician” opposing the “conclusion that a firefighter’s cancer was caused by his 

or her employment should be treated as competent evidence to rebut the presumption of causation.” 

Aikele, however, is inapplicable here because it predates Idaho Code section 72-438(14). Thus, 

there was no rebuttable presumption shifting the burden to the employer. That case concerned

whether a firefighter proved it was more probable than not his cancer was caused by his

employment, not whether his employer presented substantial evidence to rebut a presumption the 

employment caused the cancer. Even the standards of review differ. In Aikele, the Court was 

reviewing disputed factual findings to determine whether the Commission clearly erred; however, 

in this case, the Court freely reviews whether the Commission correctly applied the statutory 

presumption in Idaho Code section 72-438(14)(c). Thus, while Aikele suggests that research data 

can be a foundation for a medical expert’s opinion regarding a particular claimant, it does not 

support an employer’s attempt to generally attack the statutory presumption of causation for all 

firefighters set forth in section 72-438(14)(c). 
18

Therefore, we affirm the Industrial Commission’s findings of fact and conclusions of law. 

The Commission correctly determined that the City failed to present substantial evidence contrary 

to the presumption that Nelson’s CLL was caused by his occupation as a firefighter. 

C. Nelson is entitled to attorney fees. 

Nelson argues on appeal that he is entitled to attorney fees pursuant to Idaho Code section

72-804, which permits punitive costs in certain cases. It states, in pertinent part: “If the commission 

or any court before whom any proceedings are brought under this law determines that the employer 

. . . contested a claim for compensation made by an injured employee . . . without reasonable 

ground, . . . the employer shall pay reasonable attorney fees in addition to the compensation 

provided by this law.” I.C. § 72-804. 

We agree that Nelson is entitled to attorney fees under this statute. The City’s arguments 

were little more than an attack on the policy behind the 2016 legislation under the guise of a firstimpression constitutional challenge. As noted, such an assault on similar legislation has found no 

traction anywhere else it has been attempted. The City did not present reasonable grounds to 

challenge the legislature’s authority to create such a presumption; rather, it merely sought to 

second-guess and undermine the scientific basis of the statutory presumption itself. Likewise, there 

was no serious attempt to show that the presumption did not apply to Nelson. Therefore, we award 

attorney fees to Nelson as the injured claimant.

IV. CONCLUSION

Based on the foregoing reasons, we hold that Idaho Code sections 72-438(14)(b) and (c) 

are constitutional. Further, we affirm the Industrial Commission’s determination that the City 

failed to present “substantial evidence to the contrary” to rebut the presumption that Nelson’s CLL

was caused by his occupation as a firefighter. We award attorney fees to Nelson pursuant to Idaho 

Code section 72-804. As the prevailing party, Nelson is also entitled to an award of costs pursuant 

to Idaho Appellate Rule 40(a). 

Chief Justice BEVAN, Justices BRODY, STEGNER and ZAHN CONCUR.