1 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. ) ) ) ) ) ) ) ) ) ) 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 worker s’ 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 discriminate s between the employers of firefighters who have cancer and the employers of other employees who cla im to have contracted an occupational
disease. For the following reasons, we affirm the Industrial Commission.2 I. F ACTUAL AND P ROCEDURAL B ACKGROUND 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. H e was actively involved in fire prevention an d 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 l ymphocytic l eukemia (“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 examination s with the City of Pocatello, nor was the diagnosis made more than ten years following Nelson’s promotion to Captain or his ret irement 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 pr esumption with the report and testimony of Robert E. Burdick, M.D. Dr. Burdick ’s report discuss ed studies and statistics concerning the association
between CLL and firefight ing

. 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 incr ease 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 a nd 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 lymphocytes3 within the bone marrow. Nelson’s CLL diagnosis was discovered early eno ugh 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 corr ect and I don’t misstate it. I believe you say that a physician cannot conclude with medic al 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 C ity “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 somet hing other than his employment.” T he Industrial Co mmission also concluded that Idaho’s firefighter presumption law, enacted in 2016, was unambiguous ; it plainly require s the Commission “to presume, unless there
is ‘ substantial evidence to the contrary ’ , [sic] that a claimant ’ s disease was proximately caus ed 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

. S TANDARD OF R EVIEW The standard of review for appeals from the Industrial Commission is two

- fold : (1) while
this Court free ly 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 treat ment , determining prognosis, and ascertaining the risks for patients with c hronic lymphocytic leukemia (CLL)

.4 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).
“Const itutional 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 Trans p. , 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 resol ved 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 m ust 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

. A NALYSIS 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. Th e 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 add ress 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 co nsider the City’s argument on the statute’s constitutionality.
A. Idaho Code secti ons 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 standar d in Idaho Code § 72

- 438(14)(c) for overcoming the5 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 pr ovisions 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 conce des 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 qu alify for
rational basis review, and it does not violate either the U.S. or Idaho Constitutions. We agree with
Nelson’s an alysis. 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 appli cable 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 s imilar 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
constitution s because neither a suspect class nor a fundamental right are involved in this case. However, t he parties dispute whether Idaho’s “ means

- focus” test or a rational basis test applies,6 and whether the appropriate test is satisfied. While t he City alleges a violation of the Fourteenth
Amendment’s rational basis standard , it does so without any accompanyi ng 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 e ach step of our equal protec tion 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 occupat ional 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 occupat ional 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

em ployment as a firefighter: . . .

2 In t he 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 Develop ments in Workers’ Compensation Law , 39 T ORT T RIAL & I NS

. P RAC

. 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. R ICH

. L. R EV

. 475, 509 (2004) (“Catastrophic events, such as natural disasters and the tragic and unnerving events of September 11, 2001, have already catalyzed deba te 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 o f occupational diseases for firefight ers

. 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 2 8 , 2022).7 (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 firefighte r 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 di sease 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 firefight er 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 di agnosis. I.C. § 72

- 438(14). Specifically at issue in th is 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

m eans

- focus test or the rational basis test must apply to the alleged unconstitutional discriminati on. 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 test s

. T he 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 [

. ] ” Gomersal l , 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 requires8 a determination of whether different treatment is accorded to persons on the basis of criteria wholly

unre lated 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 a pparent 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 statut ory presumption is not intended to punish such employers; rather, the presumption protects firefighters as an occupational class at greater ris k o f contracting c ancers due to the nature of their work.
Neither the text of section 72

- 438, its legislative history
, nor common sense suggest s 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 addre sses 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 gen eral 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 pa rt 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 include d 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 canc ers are attributable to occupational exposures,” and firefighters are “routinely exposed to mixtures of chemical substances” contained in fire smoke and building debris. Medical studies9 of groups of firefighters, while varied , indicate a statistically sign ificant increased risk of firefighters to develop the bill’s listed cancer s , 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 revea led 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 period s , 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 t o 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. A s 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 Owen s , an attorney representing in jured 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 speci fic 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 particula r 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 Resou rces Committee Meeting (March 3, 2016, 1:3 0 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).
T his 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 b urdens 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 evid entiary burden back to a claimant upon showing substantial10 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 ratio nal 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, t he 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 employ ee s determined to face unique risks: firefighters

. Such concerns have traditionally been reviewed under a rational basis analysis. See id. Likewise, b ecause neither the means

- focus nor strict scrutiny standards apply to the classification at issue, we must apply the rational bas is test and next determine whether the test is satisfied. See id.
4. The protections afforded firefighters in Idaho Code section s 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 a t 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)

.11 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 burd en 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 worker s’ compensation l aws 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 legislat ive 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 correct ly determin ed 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 r ebut 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
contend s 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

.12 Idaho’s worker s’ compensation laws contain num erous 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 indic ated 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 f irefighter 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 contrar y. 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,” “ s ubstantial evidence to the contrary” does not hav e 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 contra dicting the presumption that a n individual claimant’s cancer was caused by his work as a firefighter. In other wor ds, 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 “substantia l 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 issue13 here

. For instance, Idaho Code section 72

- 228 provides a rebuttable presumption of causation in
certai n 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 th e 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, i n 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

- 2 0 8 (1976) and I.C. § 72

- 228 ). The Hatley Court determined the
workers’ compensation statutes required 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. A n 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 indica ted “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 , t he 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

aros e 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 an d 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, hyper triglyceridemia, 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 eviden ce 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 let ter. ” 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 presumpti on. 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 b y 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. H owever, Dr. Burdick ’s foundation for his report was solely based on evidence that firef ighting, in general, does not significantly
increase the risk of cancer on a more

- probable

- than

- not basis. In other words, Dr. Burdick’s report

s ought to rebut the presumption not by showing an alternate cause for Nelson’s CLL , but by attacking the evident iary 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 just15 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 r adon or that his CLL was actually caused by radon. Indeed, the doctor concede d
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, exposure s to toxins while firefighting, or oth erwise : 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 L egislature’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. Burdic k should have directed his research and testimony
towards Nelson’s CLL and offered proof of an alternative cause for it. Ultimately , t he City’s evidence appears to only challenge the statut ory presumption itself
, rather than rebut the presumption that Nels on’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 b y 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 L egislature was concerned wit h: 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 t o 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 s tate appellate courts hav e long rejected similar attempts by employers to disprove the underlying premise of a legislati vely creat ed presumption
, rather than rebut ting 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. Shankl e , 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 Manch ester 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 insuffic ient 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 th an question the wisdom of the legislature .”). It is clear from the plain reading of the statute that the L egislature intended to create a
rebuttable presumption that firefighters diagnosed with certain types of cancer qualify for workers’ compensation ben efits 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 t he 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 affirmativ e 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. T he 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 lang uage and holding from Ai kele 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,

t here 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

. I n Aikele , the Court was reviewing disputed factual findings to determine whether the Commiss ion 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 exp ert’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 entitle d 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 com pensation 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 first

impression cons titutional 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 ground s 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. T herefore , we award attorney fees to Nelson as the injured cl aimant.
IV

. C ONCLUSION 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 CL L was caused by his occupation as a firefighter

. We award attorney fees to Nelson pursuant to Idaho
Code section 72

- 804. As the prevailing par ty, 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.