Open Decision Ledger · Labour & industrial accidents
Substantial causation where research on the occupational disease is insufficient
Supreme Court, Jan. 9, 2025, 2024Du45979 (judgment)
No holding summary · checked against points at issue. The official text publishes no summary of the holding for this decision. The quotation and factors in this record are copied verbatim from the points at issue; the evidence for each axis is taken from the points at issue, the order and the reasons.
Case name: 요양불승인처분취소
Official text on the National Law Information Center
Question
In a claim for medical benefits under the Industrial Accident Compensation Insurance Act, where research on the worker's disease is not sufficient to establish a clear link, how is substantial causation between the work and the onset or aggravation of the disease assessed?
Holding
Causation need not be proved with medical or natural-scientific certainty; substantial causation in a legal and normative sense suffices, and it is judged by the worker's own health and physical condition rather than by those of an average person. Research that is not sufficient to establish the link between the suspected factor and the disease cannot by itself defeat causation, and the purpose and social function of the industrial accident compensation insurance must be reflected normatively in the assessment. Weighing the circumstances together, the Court saw room to find substantial causation between A's work and the onset or aggravation of the thyroid papillary carcinoma, and reversed the judgment below.
Points at issue, verbatim
제반 사정을 종합하면 갑의 업무와 상병의 발병·악화 사이에 상당인과관계를 긍정할 여지가 있다고 한 사례
Unofficial English translation
a case in which it was held that, upon an overall consideration of the circumstances, there remains room to affirm adequate causation (proximate cause) between A's Work and the onset and aggravation of the illness
Disposition
Reversed and remanded Stated in the decision
원심판결을 파기하고, 사건을 서울고등법원에 환송한다.
Unofficial English translation
The judgment of the court below is reversed, and the case is remanded to the Seoul High Court.
Form of the test
Elements stated Stated in the decision
여기에서 말하는 인과관계는 반드시 의학적·자연과학적으로 명백히 증명되어야 하는 것은 아니고 법적·규범적 관점에서 상당인과관계가 인정되면 그 증명이 있다고 보아야 한다.
Unofficial English translation
The causation referred to herein need not necessarily be proved clearly in medical or natural-scientific terms; if adequate causation (proximate cause) is recognized from a legal and normative perspective, such proof should be regarded as having been made.
Factors
- 업무와 질병 사이의 인과관계에 관한 증명책임의 소재 및 증명의 정도
- 업무와 질병 사이의 인과관계를 판단하는 방법 및 판단의 기준이 되는 자
- 산업재해보상보험제도의 목적과 사회적 기능이 규범적으로 조화롭게 반영되어야 하는지 여부(적극)
- 발병원인으로 의심되는 요소들과 근로자의 질병 사이에 인과관계를 명확하게 규명하는 것이 곤란하다는 이유만으로 인과관계를 부정할 수 있는지 여부(소극)
- 제반 사정을 종합하면 갑의 업무와 상병의 발병·악화 사이에 상당인과관계를 긍정할 여지가 있다고
Unofficial English translation
• The allocation of the burden of proof and the degree of proof required for causation between work and disease
• The method for determining causation between work and disease and the person serving as the basis for such determination
• Whether the purpose and social function of the Industrial Accident Compensation Insurance system must be reflected in a normatively harmonious manner (affirmative)
• Whether causation may be denied on the sole ground that it is difficult to clearly establish causation between factors suspected as causes of onset and the worker's disease (negative)
• Upon an overall consideration of the circumstances, there remains room to affirm adequate causation (proximate cause) between A's Work and the onset and aggravation of the illness
Relation to precedent
Follows earlier decisions Stated in the decision
대법원 2007. 4. 12. 선고 2006두4912 판결(공2007상, 722), 대법원 2008. 5. 15. 선고 2008두3821 판결, 대법원 2017. 8. 29. 선고 2015두3867 판결(공2017하, 1860)
Unofficial English translation
Supreme Court Decision 2006Du4912 decided April 12, 2007 (Gong 2007 Sang, 722), Supreme Court Decision 2008Du3821 decided May 15, 2008, Supreme Court Decision 2015Du3867 decided August 29, 2017 (Gong 2017 Ha, 1860)
Decisions referred to
[1][2][3] 대법원 2007. 4. 12. 선고 2006두4912 판결(공2007상, 722), 대법원 2008. 5. 15. 선고 2008두3821 판결, 대법원 2017. 8. 29. 선고 2015두3867 판결(공2017하, 1860)
Burden of proof
The party asserting Stated in the decision
업무와 질병 사이에 인과관계가 있어야 하고 그 증명책임은 원칙적으로 근로자 측에 있다.
Unofficial English translation
There must be causation between work and disease, and the burden of proof lies, in principle, on the worker's side.
Open question and revisit condition
How high must measured exposure be before a workplace counts as holding a harmful factor at a certain level or above, and how should directly conflicting research results be weighed against each other?
New research establishing or excluding a significant link between extremely low frequency magnetic fields and thyroid cancer would change how the conflicting results were weighed here, and the remand judgment of the Seoul High Court will show how the individual standard was applied to these facts.
Cross-family AI independent reading & axis check
5 of 8 axes matched GPT-6 Astra (OpenAI, codex CLI) · 2026-10-25
A reader from another model family (GPT-6 Astra), given the official text but not the primary reading, agreed on 5 of the 8 axes; the readings differed on axis 4 (form of the test), axis 5 (factors), axis 8 (open question and revisit condition).
Axis 4 (Form of the test): Primary “Elements stated” vs Independent “Circumstances weighed”
The primary reading frames the decision as stating requirements, while the independent reading frames it as an overall weighing of circumstances.
제반 사정을 종합하면 갑의 업무와 상병의 발병·악화 사이에 상당인과관계를 긍정할 여지가 있다고 한 사례Axis 5 (Factors): Primary “업무와 질병 사이의 인과관계에 관한 증명책임의 소재 및 증명의 정도 / 업무와 질병 사이의 인과관계를 판단하는 방법 및 판단의 기준이 되는 자 / 산업재해보상보험제도의 목적과 사회적 기능이 규범적으로 조화롭게 반영되어야 하는지 여부(적극) / 발병원인으로 의심되는 요소들과 근로자의 질병 사이에 인과관계를 명확하게 규명하는 것이 곤란하다는 이유만으로 인과관계를 부정할 수 있는지 여부(소극) / 제반 사정을 종합하면 갑의 업무와 상병의 발병·악화 사이에 상당인과관계를 긍정할 여지가 있다고” vs Independent “산업재해보상보험제도의 목적과 사회적 기능 / 근로자에게 발병한 질병에 관한 연구결과가 충분하지 않아 / 상시적으로 22,900V의 특고압 전기가 흐르는 상태에서 작업을 하면서 / 극저주파 전자기장 등 전자파에 노출되었고 / 전기를 만진다는 강박감과 과도한 스트레스”
The primary reading lists legal criteria such as the burden of proof and the social function of insurance, while the independent reading lists the worker's specific exposure facts, so the overlap is less than half.
산업재해보상보험제도의 목적과 사회적 기능Axis 8 (Open question and revisit condition): Primary “How high must measured exposure be before a workplace counts as holding a harmful factor at a certain level or above, and how should directly conflicting research results be weighed against each other?” vs Independent “On remand, will the full assessment of this worker's circumstances establish a substantial causal relationship between the work and the onset or aggravation of thyroid cancer?”
The primary reading asks about exposure thresholds and conflicting research, while the independent reading asks whether causation will be found on remand.
제반 사정을 종합하면 갑의 업무와 상병의 발병·악화 사이에 상당인과관계를 긍정할 여지가 있다고 한 사례Raw responses and comparison record: Protocol · Blind readings (JSONL) · Axis comparison (JSONL) · SHA-256 (JSON)
Lower-court contrast & scope of application
Lower-court reading vs. Supreme Court holding
Lower-court context: The Seoul High Court, in its judgment of 11 June 2024 (2022Nu55868), held that the denial of medical benefits to A was lawful. The denial decision of 4 March 2020 had reasoned that research supporting a link between exposure to extremely low frequency magnetic fields and the occurrence of thyroid cancer is lacking, that no occupational exposure to harmful factors known to be associated with thyroid cancer was found, and that the incidence of thyroid cancer among electricians is not unusually high.
Supreme Court standard: The Supreme Court held that the court below had misapprehended the law on substantial causation between work and the accident under the Industrial Accident Compensation Insurance Act, and that the error affected the judgment. It pointed out that the finding that the suspected exposure cannot be linked to the disease by clear research is not by itself a ground to deny causation, that the lack of comparable data on live-line linemen cannot be read as scientific absence of harm, and that prolonged high exposure, excessive mental stress and the worker's own constitution may have combined to bring on or aggravate the disease. It reversed the judgment below and remanded the case to the Seoul High Court on the unanimous opinion of the participating Justices.
Distinguishing conditions
- A case in which sufficient research establishes or excludes a link between the suspected factor and the disease, so that the rule on insufficient research does not decide the matter.
- A workplace in which no harmful factor is present at the level the Court relied on, since the Court spoke of a harmful factor existing at a certain level or above.
- A case in which the main cause of the disease has no direct link to the performance of work and work-related overwork or stress did not combine with it, since the overlapping-cause rule applies only then.
Record verification notes
Set A's actual exposure records, work period and work method against the 2017 survey figures the Court relied on, an average of 1.3μT and a maximum range of 8.5 to 1,671μT for live-line workers. Then test what the denial decision rests on: where it rests on the absence of research alone, this decision speaks directly to it, while findings on occupational or medical factors must be examined one by one. Finally gather A's health at entry to the job, any prior treatment, family history and any other harmful factors at the site, since causation is judged by this worker's own health and physical condition.
From the official text
Points at issue
[1] 산업재해보상보험법 제5조 제1호가 정하는 업무상의 사유에 따른 질병으로 인정하기 위한 업무와 질병 사이의 인과관계에 관한 증명책임의 소재 및 증명의 정도 / 업무와 질병 사이의 인과관계를 판단하는 방법 및 판단의 기준이 되는 자 [2] 산업재해보상보험 지급 여부의 결정적 요건인 업무와 질병 사이의 인과관계를 판단하는 과정에서 산업재해보상보험제도의 목적과 사회적 기능이 규범적으로 조화롭게 반영되어야 하는지 여부(적극) [3] 근로자에게 발병한 질병에 관한 연구결과가 충분하지 않아 발병원인으로 의심되는 요소들과 근로자의 질병 사이에 인과관계를 명확하게 규명하는 것이 곤란하다는 이유만으로 인과관계를 부정할 수 있는지 여부(소극) [4] 배전전기원으로 근무하던 갑이 ‘상시적으로 22,900V의 특고압 전기가 흐르는 상태에서 작업을 하면서 극저주파 전자기장 등 전자파에 노출되었고, 전기를 만진다는 강박감과 과도한 스트레스로 갑상선 유두상암이 발병하였다.’며 근로복지공단에 요양급여를 신청하였으나, 근로복지공단이 ‘극저주파 자기장 노출과 갑상선암 발생과의 인과성을 뒷받침할 연구가 부족하고 갑상선암과 관련 있는 것으로 알려진 유해인자의 직업적 노출이 없다.’는 등의 이유로 요양을 불승인하는 결정을 한 사안에서, 제반 사정을 종합하면 갑의 업무와 상병의 발병·악화 사이에 상당인과관계를 긍정할 여지가 있다고 한 사례
Unofficial English translation
[1] The allocation of the burden of proof and the degree of proof required for causation between work and disease in order to recognize a disease as a disease arising from a cause related to work under Article 5, subparagraph 1 of the Industrial Accident Compensation Insurance Act / the method for determining causation between work and disease and the person serving as the basis for such determination [2] Whether, in the course of determining causation between work and disease, which is a decisive requirement for determining whether Industrial Accident Compensation Insurance benefits are payable, the purpose and social function of the Industrial Accident Compensation Insurance system must be reflected in a normatively harmonious manner (affirmative) [3] Whether causation may be denied on the sole ground that research findings on a disease that has developed in a worker are insufficient and that it is difficult to clearly establish causation between factors suspected as causes of onset and the worker's disease (negative) [4] In a case where A, who worked as a distribution electrician, applied to the Korea Workers' Compensation & Welfare Service for medical care benefits on the ground that "while working in a state in which extra-high-voltage electricity of 22,900V was constantly flowing, he was exposed to electromagnetic waves such as extremely low frequency electromagnetic fields, and he developed papillary thyroid carcinoma due to an obsessive preoccupation with having touched electricity and excessive stress," and the Korea Workers' Compensation & Welfare Service rendered a decision denying medical care on the grounds that "there is an insufficient body of research supporting a causal relationship between exposure to extremely low frequency magnetic fields and the occurrence of thyroid cancer, and there is no occupational exposure to harmful factors known to be associated with thyroid cancer," a case in which it was held that, upon an overall consideration of the circumstances, there remains room to affirm adequate causation (proximate cause) between A's Work and the onset and aggravation of the illness
Summary of the holding
The official text publishes no summary of the holding for this decision. The quotation and factors in this record are copied verbatim from the points at issue; the evidence for each axis is taken from the points at issue, the order and the reasons.
Order
원심판결을 파기하고, 사건을 서울고등법원에 환송한다.
Unofficial English translation
The judgment of the court below is reversed, and the case is remanded to the Seoul High Court.
Provisions referred to
[1] 산업재해보상보험법 제5조 제1호, 제37조 제1항 [2] 산업재해보상보험법 제5조 제1호, 제37조 제1항 [3] 산업재해보상보험법 제5조 제1호, 제37조 제1항 [4] 산업재해보상보험법 제5조 제1호, 제37조 제1항
Read 2026-10-25 · Cross-read 2026-10-25. All quotes matched against the official text. The Chinese-character placeholders the court used for anonymised parties are given in their Korean readings, and parenthetical Chinese-character glosses are omitted.
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