Statement of Principles concerning chronic myeloid leukaemia (Reasonable Hypothesis) (No. 57 of 2023)

The core concept is reasonable hypothesis, a standard of proof unique to Australian veterans' law. It is not proof on the balance of probabilities; rather, a hypothesis that is reasonable must be raised, meaning there must be some material pointing to a connection between service and the condition that is consistent with the known medical-scientific evidence. The Authority has determined (section 8) that there is sound medical-scientific evidence that CML can be related to relevant service, and this instrument specifies the only factors that can ground a reasonable hypothesis. The factors themselves are the central machinery. The instrument defines CML in section 7(2) as a malignant neoplasm of the blood with predominant overpopulation of myeloid cells and the presence of a Philadelphia chromosome or BCR-ABL1 gene or gene product. Notably, it excludes several similar conditions: atypical CML, chronic eosinophilic leukaemia, chronic neutrophilic leukaemia, leukemoid reactions, and myelomonocytic leukaemia. This narrow definition matters: claimants with those excluded conditions cannot rely on this SoP, even if their service exposure history fits. The factor list in section 9 contains seven items, but six are physical or exposure based. The seventh (inability to obtain appropriate clinical management) operates differently, applying only to material contribution or aggravation, not original onset (section 10(2)). Key exposure concepts include cumulative equivalent dose of ionising radiation, which is calculated according to an ARPANSA guide excluding normal background radiation; the threshold is a very low 0.01 sievert to the bone marrow. For benzene, there are two alternative metrics: an hour-based test (at least 2,500 hours within a continuous 5-year period, with exposure defined as cutaneous contact with >1% benzene liquids, ingestion, or inhalation at >5 ppm 8-hour TWA), and a ppm-years cumulative exposure test (>10 ppm-years). Both require the first exposure at least 5 or 10 years before onset, and last exposure within 30 years before onset. The obesity factor requires being obese (BMI >=30) for at least 10 years within the 20 years before clinical onset. Notably, kidney transplant has no latency period mentioned. Understanding these definitions requires cross-referencing the Schedule 1 dictionary, which includes terms like "8-hour time-weighted average" and "BMI". The concept of terminal event in section 7(5) extends the definition of death from CML to include deaths contributed to by CML where the immediate cause is pneumonia, respiratory failure, cardiac arrest, circulatory failure, or cessation of brain function. This expands the pool of compensable deaths beyond those directly due to the cancer.

The primary affected population is veterans and members of the Australian Defence Force who have rendered relevant service as defined in the Schedule 1 dictionary: operational service, peacekeeping service, hazardous service, or British nuclear test defence service under the VEA, and warlike or non-warlike service under the MRCA. This covers most former and current military personnel who have served in designated capacities, including peacekeepers, those exposed to hazardous environments, and participants in British nuclear tests. The instrument directly affects claimants who have been diagnosed with CML, or who die from it, and who seek compensation for incapacity, medical expenses, or death benefits under either the VEA or MRCA. Their legal representatives, advocates, and claims officers within DVA must understand the specific factor requirements to prepare submissions and make decisions. Medical professionals engaged to provide opinions on causation must also refer to the SoP: a doctor's report that merely asserts a generic connection to service without identifying a specific factor will not ground a reasonable hypothesis. The instrument thus imposes a compliance burden on the entire claims ecosystem. Additionally, the Authority itself is affected because it must periodically review and update SoPs as medical science evolves; this instrument reflects that ongoing process. Taxpayers bear the indirect cost of any successful claims that flow from the instrument, though the Authority does not quantify that cost. Economically, the instrument concentrates benefits on a small population of CML sufferers (estimated incidence of about 1-2 per 100,000 per year) while the costs are spread across all taxpayers. There is a risk of rent-seeking behaviour: claimants may attempt to stretch the definitions of exposure (e.g., reconstructing benzene exposure from military service records to meet the 2,500-hour threshold). The instrument's precision in defining exposure metrics (e.g., "8-hour time-weighted average exceeding five parts per million") attempts to limit this, but verification of historical exposure will often be difficult, imposing high transaction costs. Conversely, the instrument may undercompensate veterans whose CML is genuinely service related but whose exposure does not fit the prescribed factors, leading to false negatives. The instrument does not affect those with excluded leukemias, who must look to other SoPs.

The instrument itself creates no duties on private individuals; it is a tool for decision-makers. The key right it creates is the right of a claimant to have their claim assessed using these factors as the exclusive pathway for establishing a reasonable hypothesis for CML. If a claimant raises one of the factors in section 9 and can demonstrate that the factor is related to relevant service, the decision-maker must accept that a reasonable hypothesis exists, and then proceed to the question of whether the hypothesis is disproved beyond reasonable doubt (for operational service claims) or on the balance of probabilities (for peacekeeping/hazardous service). The instrument does not create a right to compensation; it only establishes the causation gateway. Section 10 imposes an implicit duty on decision-makers to ensure that the factor is related to the person's relevant service. For example, a veteran who was obese for ten years but whose obesity was not caused or aggravated by service will not succeed under factor 9(3) unless the obesity itself was service related. Section 10(2) specifically limits the application of factor 9(7) (inability to obtain appropriate clinical management) to cases where the CML was contracted before or during service (but did not arise out of service). This means that factor cannot be used to establish original causation; it can only cover aggravation or material contribution. This is a significant limitation that claimants and advocates must understand. Under section 11, where a factor refers to another injury or disease for which a separate Statement of Principles exists, the factors from that other SoP apply as in force from time to time. This creates a layered duty: decision-makers must keep abreast of amendments to related SoPs that affect the interpretation of a factor in this instrument. For example, if a veteran's CML factor relies on having received a kidney transplant (factor 9(6)), and kidney disease itself might be related to service under another SoP, that other SoP's factors come into play. This cross-referencing can significantly expand the analysis required. Claimants have the right to rely on the instrument as an authoritative statement of what the Authority considers sufficient to raise a hypothesis, and they also have a right to have the instrument applied correctly, including the right to challenge decisions that misapply it. However, no private right of action exists; enforcement is through the statutory claims and review process under the VEA and MRCA.

This instrument is not a penal statute and contains no penalty provisions. Enforcement is indirect and occurs through the claims determination process: if a claimant fabricates exposure evidence to meet a factor, they may face prosecution under section 205 of the VEA (false statements to obtain a pension) or similar provisions under the MRCA, which carry penalties including imprisonment. The instrument itself, however, only lists factors; it does not prescribe penalties for non-compliance. For decision-makers, the penalty for misapplying the SoP is that their decision is likely to be set aside on review. The Administrative Appeals Tribunal and the Federal Court serve as the enforcement mechanism for correct application. The instrument's legal effect is that it binds the Repatriation Commission and the Military Rehabilitation and Compensation Commission. If a decision-maker fails to apply the instrument correctly, the claimant can seek merits review. There are no fines or direct consequences for the decision-maker personally, but systemic non-compliance could lead to adverse findings in individual cases. Practically, the instrument raises the cost of error: if a DVA delegate incorrectly rejects a claim that could have succeeded under one of the factors, the claimant will appeal, increasing government costs through litigation and back-payment of arrears. Conversely, if a claim is improperly granted because a factor was misinterpreted, there may be no mechanism to claw back compensation beyond judicial review within time limits. The instrument thus creates incentives for conservative decision-making, as delegates may err on the side of refusing claims to avoid being seen as too generous, leading to more appeals. The net effect on government outlays depends on the balance of these errors. The instrument does not provide any private enforcement rights; only the claimant or the commission can seek review.

The instrument is made under subsection 196B(2) of the VEA, which is within Part XIA of that Act. It operates in conjunction with the standard of proof provisions in section 120A of the VEA and section 338 of the MRCA. Those provisions direct how the SoP is to be applied: for operational service claims, the reasonable hypothesis once raised must be disproved beyond reasonable doubt; for peacekeeping, hazardous, and MRCA claims, it is the balance of probabilities. The instrument does not override those standards; it only provides the factors for raising the hypothesis. Section 11 of the instrument explicitly incorporates other Statements of Principles where a factor refers to an injury or disease that is the subject of a separate SoP. For example, if the factor is "having received a kidney transplant", and the kidney disease leading to transplant is itself a condition that could be service related under another SoP, the factors from that other SoP must be applied to determine whether the kidney transplant factor is met. This creates a network of interlocking instruments. The instrument also interacts with the ICD-10-AM classification: section 7(3)-(4) assigns code C92.1 to CML but clarifies that the instrument's own definition prevails. This is important because the ICD code may be updated, but the instrument's definition remains static unless amended. The definition of "cumulative equivalent dose" incorporates the ARPANSA guide as in force on 2 August 2017, freezing that methodology. Any subsequent changes to the ARPANSA guide do not automatically update this instrument, potentially creating inconsistency if radiation science evolves. The instrument repeals the 2014 SoP, so prior claims decisions that relied on that older instrument may need to be reconsidered if a claim is reopened. However, the instrument applies only to claims made after its commencement or to claims not yet finally determined. There is no interaction with state workers' compensation laws, as veterans' entitlements are exclusively federal. The instrument does not directly interact with criminal law, immigration law, or commercial law, save that evidence of workplace benzene exposure during service might involve reference to occupational health and safety records.

This instrument (No. 57 of 2023) is a standalone legislative instrument that repeals and replaces the previous Statement of Principles concerning chronic myeloid leukaemia (No. 47 of 2014, registered as F2014L00479). The previous instrument was itself a replacement for older versions. Neither the 2014 instrument nor its predecessors are reproduced here, but the Authority's decision to issue a new instrument suggests that the medical-scientific evidence base for CML causation has changed sufficiently since 2014 to warrant updated factors. The most visible new factor is obesity (section 9(3)), which was not present in the 2014 version. The addition of a second benzene metric (ppm-years in section 9(5)) alongside the existing hours-based metric (section 9(4)) indicates that the Authority now recognises alternative cumulative exposure measures as sufficient. The kidney transplant factor (section 9(6)) was likely present previously, as it is a known medical risk factor for CML. The instrument does not include any transitional provisions, so it applies to all claims made on or after 23 May 2023, and to claims made before that date but not yet finally determined, by virtue of the application provision in section 5 read with the relevant procedural rules. There is no explanatory memorandum or extrinsic material accompanying this instrument in the source provided, so the precise reasoning for changes is not available. However, the Authority is required under the VEA to review SoPs periodically and to keep them consistent with current medical science. The amendment history of previous instruments is not detailed, but legal practitioners should note that the 2014 instrument was itself the product of earlier reviews. Any future amendment will similarly repeal this instrument. Given the pace of research into leukaemia aetiology, practitioners should monitor the Federal Register of Legislation for further updates.

The source text does not cite any litigation history. However, in the broader context of veterans' law, Statements of Principles have been the subject of extensive litigation in the Administrative Appeals Tribunal and federal courts, often concerning the interpretation of specific factors, the meaning of "reasonable hypothesis", and the scope of the Authority's discretion. For this particular instrument, being new, there is not yet any case law. However, the predecessor instruments (particularly No. 47 of 2014) would have been litigated. Common disputes in CML claims likely include: whether the standard of proof for the factor itself (e.g., proving the veteran received 0.01 Sv to bone marrow) requires direct measurement or can be inferred from service history; whether the benzene exposure definitions can be satisfied by military occupational exposure (e.g., refuelling, solvent use); and whether the obesity factor requires the veteran to show that the weight gain was specifically service related. The interaction with section 10(2) (limitation on clinical management factor) is likely to generate disputes, as claimants may try to use that factor for original onset. The exclusion of atypical CML and other leukemias may also be contested in borderline diagnostic cases. Economic analysis suggests that the instrument's precision may reduce litigation relative to a more general standard, as the factors are relatively specific. However, the low threshold for ionising radiation (0.01 Sv) is likely to be the most heavily litigated, as many veterans may have accumulated such doses from medical procedures or overseas deployments. Costs of litigation fall on both sides: claimants often have legal aid or advocacy funded by the taxpayer, while DVA employs lawyers and instructs counsel. The net effect on judicial resources is likely neutral.

Several subtle traps exist for claimants and decision-makers. First, the obesity factor (section 9(3)) requires being obese (BMI >= 30) for at least 10 years within the 20 years before clinical onset. The definition of "being obese" in the dictionary uses a simple BMI formula, but the temporal requirement is tricky: it is not simply being obese before onset, but a cumulative duration of 10 years out of a 20-year window. A veteran who was obese for 9 years and 11 months will not satisfy the factor. Furthermore, the obesity must itself be related to service (section 10(1)), so obesity that developed exclusively after service due to civilian lifestyle does not count. Second, the inability to obtain appropriate clinical management factor (section 9(7)) applies only to material contribution to or aggravation of CML where the CML was suffered or contracted before or during service but did not arise out of that service (section 10(2)). This is a narrow provision: it cannot be used to claim that failure to diagnose or treat CML during service caused the initial onset. Third, the benzene exposure factors have overlapping but non-identical time conditions. The hours-based factor (section 9(4)) requires first exposure at least 5 years before onset and last exposure within 30 years before onset, with a cumulative 2,500 hours within a continuous 5-year period. The ppm-years factor (section 9(5)) requires first exposure at least 10 years before onset, last exposure within 30 years, and cumulative >10 ppm-years. Claimants cannot mix and match conditions; they must satisfy one or the other entirely. Fourth, the ionising radiation factor (section 9(1)) uses a very low dose threshold of 0.01 Sv. However, the dose is specifically to the bone marrow, and is calculated excluding normal background radiation in Australia. Medical diagnostic exposure (e.g., CT scans) can quickly reach this level, but must be calculated using the ARPANSA guide methodology as at 2 August 2017. If a veteran had multiple CT scans during service, the cumulative dose might be sufficient, but the guide may attribute dose only to the organ, not whole body. Practitioners must obtain the ARPANSA guide and follow its methodology precisely. Fifth, the definition of chronic myeloid leukaemia in section 7(2) excludes several similar conditions. A diagnosis of "atypical CML" or "chronic myelomonocytic leukaemia" will not fall under this SoP, even if the exposure factors are present. Claimants may need to apply under a different SoP for their specific leukaemia subtype. Sixth, the note in section 7(2) lists alternative names (chronic granulocytic leukaemia, chronic myeloblastic leukaemia, etc.), but those are synonyms; the instrument's definition prevails. Seventh, for death claims, section 7(5) extends coverage but only if the terminal event was contributed to by CML. Proximate cause must still link back. Eighth, because section 11 incorporates factors from other SoPs where a factor refers to another injury or disease, a simple factor like kidney transplant can open a can of worms: the decision-maker must then apply the kidney disease SoP to see if the transplant need was service related. This cross-referencing can catch advocates off guard.

Compliance with this instrument is an issue for two main groups: veterans and their representatives making claims, and DVA/MRCC decision-makers assessing them. For claimants, the first step is to secure a firm diagnosis of CML that satisfies the definition in section 7(2), excluding the specified other leukaemias. A pathology report documenting Philadelphia chromosome or BCR-ABL1 rearrangement is essential. Then, the claimant must identify which of the seven factors in section 9 might apply. This involves gathering service records, medical records, and exposure history. For the ionising radiation factor, the claimant should collate all records of medical imaging (X-rays, CT scans, nuclear medicine), occupational exposure records (e.g., if the veteran worked with radioactive sources), and deployment records (e.g., British nuclear test participation). A radiation physicist may need to calculate the cumulative equivalent dose to bone marrow using the ARPANSA guide. The low threshold (0.01 Sv) means many veterans will have exceeded it from medical diagnostics alone, but the dose must be related to service, not civilian healthcare. For the benzene factors, the claimant must produce evidence of exposure to benzene >1% in liquids or >5 ppm TWA in air, with durations quantified. Military employment records, safety data sheets, and witness statements may help. The obesity factor requires documenting weight and height over time to show 10 years of BMI >=30 within the 20 years before onset. Claimants should obtain medical records showing weight at various points. If no factor can be raised, the claim will fail regardless of other evidence. If a factor can be raised, the claimant must also show that the factor is related to relevant service (section 10). This is where most disputes arise: for example, a civilian CT scan received while on home leave may not be "related to service" unless the scan was for a service-incurred condition. Legal representatives should frame the connection carefully. For decision-makers at DVA, compliance requires systematic checking of each factor against the evidence. The decision-maker must first confirm the CML diagnosis meets the definition. Then for each factor raised, verify that all conditions (latency periods, exposure thresholds, etc.) are met. The instrument does not require the factor to be the sole cause, only to exist. If a factor is met and related to service, the decision-maker must accept a reasonable hypothesis exists. The only further question is whether the hypothesis is disproved. Decision-makers should maintain a checklist for each factor. The incorporation of other SoPs under section 11 requires decision-makers to have access to the current versions of all relevant SoPs. Training for delegates should cover the new obesity factor and the dual benzene metrics. The instrument imposes no formal compliance deadlines, but procedural fairness requires that claimants be given an opportunity to address deficiencies. Both sides should be aware that the instrument, once satisfied, creates a legal presumption that cannot be arbitrarily dismissed. Record keeping is critical: all exposure reconstructions should be documented and retained. For the Commonwealth, proper application of the instrument reduces litigation costs; for claimants, careful factor identification increases success chances.