Firefighter Cancer Presumption Is Substantive and Not Retroactive: Respondents’ Rights Vest at Claim Filing

Case: Vande Krol v. Industrial Commission of Arizona; Superstition Fire & Medical; Benchmark Insurance

Court: Supreme Court of the State of Arizona

Date: March 26, 2025

Citation: No. CV-23-0211-PR (vacating 255 Ariz. 495 (App. 2023))

Introduction

This case presents a recurring and statewide significant question: when a legislature eases a statutory presumption aiding claimants in workers’ compensation cases, does the more generous presumption apply to claims filed before the statute’s effective date but adjudicated afterward? The Arizona Supreme Court answers no. In a decision that clarifies retroactivity doctrine in Arizona and standardizes timing rules for workers’ compensation presumptions, the Court holds that the 2021 amendments enhancing the firefighter cancer presumption in A.R.S. § 23-901.09 are substantive, not retroactive without an express declaration, and that an employer/insurer’s corresponding substantive rights vest upon the filing of the claim. As a result, claims filed before September 29, 2021 are governed by the 2017 version of the presumption in § 23-901.01—even if hearings occur after the 2021 statute’s effective date.

The petitioner, Robert Vande Krol, a longtime firefighter diagnosed with oligodendroglioma in 2020, sought to invoke the more favorable 2021 presumption during a hearing that began days after that statute became effective. The employer and carrier argued the 2017 presumption controlled because the claim was filed in January 2021. The Court adopts the respondents’ position, vacates the court of appeals’ decision that had applied the 2021 statute, and remands for review of the ALJ’s application of the 2017 statute.

Summary of the Opinion

• No express retroactivity: Arizona’s default rule is that statutes operate prospectively. A.R.S. § 1-244 requires an express declaration for retroactive application. The 2021 firefighter presumption statute, A.R.S. § 23-901.09, contains no such declaration.
• Substantive, not procedural: The 2021 presumption materially changes the elements for establishing compensability and the burdens to rebut—eliminating the carcinogen-exposure element and heightening the rebuttal standard from a preponderance to clear and convincing evidence. Because these changes “create, define, and regulate” rights, they are substantive laws, not mere procedural rules.
• Vesting at claim filing: Respondents’ substantive rights under the governing presumption vest upon the filing of the workers’ compensation claim. This timing prevents midstream changes that would undermine fair notice and settled expectations in case preparation.
• Therefore: The 2017 version (§ 23-901.01) governs Vande Krol’s claim filed in January 2021. The Court vacates the court of appeals’ contrary ruling and remands for that court to evaluate the ALJ’s interpretation and application of the 2017 statute.

Analysis

1) Precedents and Authorities That Shape the Decision

The Court’s analysis weaves together Arizona and federal authorities addressing retroactivity, vested rights, and the nature of legal presumptions.

• Presumption against retroactivity: The Court anchors its approach in the longstanding rule that statutes are presumed prospective absent express retroactivity. See A.R.S. § 1-244; Gietz v. Webster, 46 Ariz. 261 (1935); San Carlos Apache Tribe v. Superior Court, 193 Ariz. 195 (1999); Aranda v. Industrial Commission, 198 Ariz. 467 (2000). The U.S. Supreme Court’s Landgraf v. USI Film Products, 511 U.S. 244 (1994), reinforces fairness considerations and settled expectations.
• Substantive vs. procedural: Arizona cases define substantive law as that which creates, defines, and regulates rights, while procedural law prescribes methods to enforce rights. See Hall v. A.N.R. Freight Systems, Inc., 149 Ariz. 130 (1986); Aranda, 198 Ariz. at 470 ¶ 12; Seisinger v. Siebel, 220 Ariz. 85 (2009). Although presumptions often serve procedural functions (Flores v. Tucson Gas, 54 Ariz. 460 (1939); State v. Grilz, 136 Ariz. 450 (1983)), the Court emphasizes function over labels: when a presumption restructures elements of proof and available defenses in a benefits scheme, it is substantive. The Court also cites City of Littleton v. Industrial Claim Appeals Office, 370 P.3d 157 (Colo. 2016), which similarly treated a firefighter presumption as substantive.
• Vested rights and timing: The Court relies on Hall’s vesting analysis: substantive rights to claim or defense vest when “actually assertable”—in civil litigation, upon filing. That principle is applied to workers’ compensation: respondents’ right to the governing presumption vests when the claim is filed. See also early vesting definitions in Steinfeld v. Nielsen, 15 Ariz. 424 (1913).
• “Applies to” language insufficient: The Court distinguishes Schuster v. Schuster, 42 Ariz. 190 (1933), where statutory text necessarily encompassed past facts (“have not lived or cohabited together” for five years), and shows that when the legislature intends application to pending claims, it knows how to say so expressly in session law or statutory text (listing several Arizona session laws doing just that).

2) The Court’s Legal Reasoning

a) Step 1: No express retroactivity in § 23-901.09 (2021)

Arizona’s retroactivity rule is categorical: “[n]o statute is retroactive unless expressly declared therein.” A.R.S. § 1-244. The 2021 firefighter presumption lacks any express statement of retroactivity—either in § 23-901.09 or the session law. The Court rejects arguments that the statute’s “applies to” clause in § 23-901.09(C) implicitly reaches pre-effective-date claims. That clause defines who qualifies (current and certain former firefighters) but not when the statute applies to claims already filed.

b) Step 2: The 2021 presumption is substantive

The 2021 amendments materially alter rights and obligations in a way that goes beyond mere procedure:

• Eliminates an element required under 2017 law: no need to prove exposure to a known carcinogen reasonably related to the cancer to invoke the presumption.
• Heightens rebuttal burden from preponderance to clear and convincing evidence, and narrows the rebuttal to proof of a specific non-occupational cause.

These changes redefine the nature and scope of a compensable claim and the defenses available. The “true function” is not evidentiary housekeeping; it is to reallocate and intensify burdens central to entitlement. As such, the statute is substantive and cannot be applied retroactively without an express declaration.

c) Step 3: Respondents’ substantive rights vested when the claim was filed

Applying Hall, the Court holds that respondents’ rights to the governing claims framework—including the presumption’s elements and rebuttal standards—vest upon the filing of the claim. Altering those rights while the case is pending would be manifestly unjust, particularly when a hearing was set to begin under the earlier statute and later continued (for unrelated reasons) beyond the new statute’s effective date. Using the hearing date or adjudication date as a trigger would be arbitrary and would invite gamesmanship.

d) Step 4: Application to Vande Krol’s claim

Because the claim was filed in January 2021, respondents’ rights vested under the 2017 presumption. The 2021 statute cannot be retroactively applied to this pending claim absent express legislative direction, which is lacking. The Court thus vacates the court of appeals’ contrary ruling and remands for that court to analyze whether the ALJ correctly interpreted and applied the 2017 statute.

3) The Dissent’s Position and the Majority’s Responses

Justice Montgomery would apply the 2021 statute to claims pending but unadjudicated as of its effective date, arguing:

• Text and manifest intent: Under A.R.S. § 1-211, statutes are construed to effectuate legislative intent. The “applies to” clause and the Legislature’s concurrent insurance-pricing amendments show the intent to cover then-existing firefighter populations and pending claims.
• Workers’ compensation’s remedial purpose: Article 18, § 8, and longstanding precedent require liberal construction to place injury costs on industry. Applying the 2021 presumption to pending claims furthers that constitutional design.
• No vested defense eliminated: The changes modify a rebuttable presumption; respondents can still contest causation. Hence, there’s no deprivation of a substantive defense within Hall’s meaning.
• Fairness and notice: Respondents had notice of the statutory change months before the hearing and could have adjusted strategy or sought continuances.

The majority replies that § 1-244 controls absent clear contrary timing in the statute; “applies to” does not specify retroactivity to pending claims; the presumption change is substantive; and vesting at filing secures fair notice and prevents gamesmanship. It emphasizes that the hearing date is an impermissible hinge-point and that respondents reasonably relied on the 2017 framework in building their case before the change.

4) Impact and Practical Implications

a) Immediate effects

• Which statute governs? For firefighter cancer claims filed before September 29, 2021, the 2017 presumption (§ 23-901.01) governs. For claims filed on or after September 29, 2021, the 2021 presumption (§ 23-901.09) governs—even if exposures or injuries predate 2021—because rights vest at filing and the application is prospective from that date.
• Remand scope: The court of appeals must now decide whether the ALJ correctly applied the 2017 statute to Vande Krol’s record, including whether he proved exposure to a known carcinogen reasonably related to oligodendroglioma and whether respondents rebutted the presumption by a preponderance.

b) Litigation strategy

• Claimants’ timing decisions matter: Filing dates control which presumption applies. Counsel should assess statutory landscapes before filing when a beneficial presumption is imminent.
• Respondents’ reliance interests are protected: Once a claim is filed, respondents can plan discovery and expert development around the then-governing statutory burdens without fear of midstream changes.
• No hearing-date opportunism: Attempts to time hearings around statutory changes will not alter which presumption applies, reducing incentives for continuance-based gamesmanship.

c) Legislative drafting lessons

• State intent expressly: If the Legislature wants a new presumption to apply to pending, unadjudicated claims, it should say so in the statute or session law. Examples abound in Arizona session laws expressly applying new rules to “pending actions in which trial has not commenced” or similar formulations.
• Insurance-pricing amendments are not timing directives: Allowing premium adjustments for “anticipated increased claims costs” signals awareness of fiscal impact but does not dictate that pending claims are covered.

d) Substantive characterization across jurisdictions

Arizona now aligns with jurisdictions like Colorado (City of Littleton) that treat firefighter presumptions as substantive. This characterization will influence choice-of-law and conflicts analyses, and it will generally preclude retroactive application absent clear legislative command.

Complex Concepts Simplified

• Retroactivity (A.R.S. § 1-244): A statute applies only to events after its effective date unless the Legislature expressly says it applies to earlier events or pending cases. “Applies to” language that identifies eligible persons is not the same as a retroactivity clause.
• Substantive vs. procedural law:
  • Substantive: rules that determine who wins based on rights and obligations—e.g., elements of a claim, burdens of proof, defenses.
  • Procedural: rules about how a case is processed—e.g., filing deadlines, discovery mechanics.
  When a “presumption” remodels core elements and defense burdens in a benefits scheme, it is substantive.
• Vested rights at filing: Parties’ substantive rights become “fixed” when a case (or claim) is filed. Later statutory changes typically cannot strip those rights in that case unless the Legislature clearly authorizes retroactivity.
• Burden of proof standards:
  • Preponderance of the evidence: more likely than not (≈ >50%).
  • Clear and convincing evidence: highly probable—a significantly higher bar.
• Statutory presumptions in workers’ compensation: A presumption lets a claimant satisfy causation upon meeting threshold conditions, shifting the burden to the employer/carrier to rebut within defined parameters.

Conclusion

Vande Krol sets a clear rule for Arizona workers’ compensation law and beyond: the 2021 firefighter cancer presumption is substantive, does not apply retroactively absent express legislative direction, and the governing law for a given claim is fixed at the time the claim is filed. The decision safeguards fair notice and reliance for parties, discourages gamesmanship tied to hearing schedules, and clarifies that the Legislature must speak plainly if it intends new presumptions to reach pending cases.

For future cases, the opinion’s practical effect is straightforward: claims filed before September 29, 2021 are governed by the 2017 statute; claims filed on or after that date are governed by the 2021 statute. The Court’s reasoning also serves as a drafting guidepost for the Legislature and a planning tool for practitioners navigating statutory shifts in burdens and presumptions. Finally, by remanding for analysis of the ALJ’s application of the 2017 statute, the Court ensures that the merits question—whether the evidence satisfied the earlier presumption—will be squarely addressed under the correct legal framework.