Below is the explanation in the Japanese labour-law context, consistent with your recent topics. It focuses on the employer's statutory reporting duties, internal accident handling, Labour Standards Inspection Office reporting, and the legal consequences of non-reporting or inaccurate reporting.

Reporting Workplace Injuries under Japanese Labour Law

1. Meaning and purpose

“Reporting workplace injuries” in Japan refers principally to the employer's obligation to report certain occupational injuries, illnesses, acute poisoning, and deaths to the competent Labour Standards Inspection Office (労働基準監督署).

The principal provision is Article 97 of the Ordinance on Industrial Safety and Health (労働安全衛生規則). Where a worker dies or takes leave because of an occupational accident or because of an injury, suffocation, or acute poisoning occurring during work or within the workplace or its attached buildings, the employer must report the matter to the competent Labour Standards Inspection Office.

The reporting system has two principal purposes:

1. enabling labour authorities to investigate workplace accidents;
2. collecting statistical information and identifying causes so that similar accidents can be prevented.

The Ministry of Health, Labour and Welfare expressly explains that reported accidents are used to analyse causes and develop measures to prevent recurrence.

2. Statutory framework

The principal legal framework consists of:

• Industrial Safety and Health Act (労働安全衛生法)
• Ordinance on Industrial Safety and Health, Article 97
• relevant provisions of the Labour Standards Act and its enforcement regulations
• workers' accident compensation legislation
• regulations governing safety management, machinery, hazardous substances and workplace conditions.

The employer's reporting obligation is separate from the employee's entitlement to workers' compensation.

Thus, an employer cannot ordinarily avoid reporting merely because:

• the employee receives medical treatment;
• the employer pays the medical expenses;
• the employee agrees not to make a complaint;
• the employer considers the accident “minor”; or
• the employee receives private insurance compensation.

3. When must an injury be reported?

A. Death

Where a worker dies as a result of a workplace accident or qualifying workplace injury, a report is required.

This is obviously the most serious category because the accident may trigger:

• Labour Standards Inspection Office investigation;
• inspection of the workplace;
• examination of machinery and safety systems;
• interviews with supervisors and witnesses;
• examination of work records;
• possible criminal investigation;
• workers' compensation proceedings; and
• civil liability claims.

B. Absence from work

Article 97 applies when a worker dies or takes leave because of the relevant injury, suffocation or acute poisoning.

For injuries involving four or more days of absence, the accident report is submitted as the applicable worker injury/disease report.

For less than four days, the reporting mechanism is different: the employer makes a periodic report covering the relevant quarter.

The current regulation requires electronic submission. Since 1 January 2025, electronic filing of the Worker Injury and Illness Report has been mandatory.

4. Four-day distinction

The distinction is particularly important for HR and compliance teams.

For injuries involving less than four days of leave, reports are made quarterly, by the end of the month following the relevant quarter.

Therefore, “the employee returned to work quickly” does not automatically mean that the employer has no reporting obligation.

5. What information must be reported?

The report contains information concerning matters such as:

• employer's labour-insurance number;
• business type;
• workplace name;
• workplace location;
• telephone number;
• number of regularly employed workers;
• relevant construction project where applicable;
• worker and employment-related information;
• expected period of absence;
• date and time of death, where applicable;
• date and time of accident;
• location;
• circumstances of the accident;
• a diagram where required;
• cause of the accident; and
• identity and position of the reporting person.

The current Article 97 expressly requires reporting of the occurrence time, location, circumstances, outline/diagram and cause of the accident.

This is important because the report is not simply an administrative notification. It creates an official record of the employer's understanding of what happened and why.

6. Accuracy of the report

An employer should not deliberately describe an accident as:

• a personal accident;
• a commuting accident;
• an employee's own fault;
• an unrelated medical condition; or
• an accident that never occurred,

merely to avoid regulatory attention.

Japan's Ministry of Health, Labour and Welfare specifically treats “労災かくし” (rosai kakushi)—concealing a workplace accident—as a criminal matter. Failure to make a required report or submitting a false report can attract penalties.

Consequently, HR should treat the accident report as a legal compliance document, rather than an internal public-relations document.

7. Relationship with workplace safety duties

Reporting is only one part of the employer's responsibilities.

The Industrial Safety and Health Act imposes broader duties concerning:

• prevention of dangerous conditions;
• machinery and equipment;
• hazardous substances;
• workplace environment;
• safety education;
• health protection;
• supervision;
• investigation of risks; and
• corrective measures.

Japanese Supreme Court decisions have repeatedly recognised that employers and persons exercising managerial authority may have duties to protect workers from foreseeable risks.

Consequently, an accident report should normally trigger an internal investigation rather than merely filing a form.

8. Internal accident investigation

After an injury, a prudent employer should preserve:

Physical evidence

• machinery;
• tools;
• PPE;
• safety devices;
• photographs;
• workplace layout;
• relevant materials.

Documentary evidence

• work instructions;
• risk assessments;
• safety manuals;
• training records;
• inspection records;
• maintenance records;
• working-hour records;
• shift schedules;
• previous accident reports.

Witness evidence

• injured employee's statement;
• supervisor statements;
• co-worker statements;
• contractor/subcontractor statements.

The employer should avoid changing or destroying evidence merely because it could expose a safety failure.

9. Contractors and dispatched workers

Workplace injuries involving dispatched workers require particular attention.

MHLW guidance states that where a dispatched worker suffers an injury at the dispatching workplace, both the dispatching employer and the host employer have reporting obligations, subject to the applicable reporting arrangements.

Therefore, companies using temporary or dispatched labour should have a contractual and operational procedure specifying:

1. who receives the initial injury notification;
2. who secures the accident scene;
3. who contacts emergency services;
4. who investigates;
5. who makes the statutory report;
6. what information is exchanged between host and dispatching employer; and
7. how inconsistent accounts are reconciled.

10. Workplace injury versus commuting accident

A distinction should be made between:

workplace accident (業務災害) and
commuting accident (通勤災害).

MHLW explains that commuting accidents are not included in the statistical figures based on the Worker Injury and Illness Reports because those reports concern qualifying workplace accidents rather than ordinary commuting accidents.

Therefore, HR should establish the factual circumstances before classifying the incident.

11. Employer's duty after reporting

Reporting does not terminate the employer's responsibility.

The employer should consider:

• eliminating the identified hazard;
• repairing defective equipment;
• revising work procedures;
• retraining employees;
• improving PPE requirements;
• changing staffing arrangements;
• modifying supervision;
• conducting additional risk assessments;
• investigating similar workplaces; and
• monitoring whether corrective action is actually implemented.

The underlying principle is prevention of recurrence.

12. Six important Japanese case laws

The following cases are particularly useful for understanding the legal principles surrounding workplace injury, occupational health, employer safety duties and accident prevention.

1. Dentsu Case — Supreme Court, 24 March 2000

1998 (O) No. 217 and 218

This is one of Japan's leading decisions concerning the employer's duty to protect an employee from excessive work-related physical and psychological burden.

The employee worked very long hours, his superiors were aware of the excessive workload and deterioration of his health, but appropriate measures were not taken. The Supreme Court recognised the employer's duty of care concerning the employee's physical and mental health and upheld liability principles relating to the resulting suicide.

Relevance to injury reporting:
An employer cannot view workplace harm merely as an isolated employee event. Where management knows of dangerous working conditions, it must respond appropriately.

2. Prefectural Police Inspector Case — Supreme Court, 7 March 2025

2023 (Ju) No. 927

The Supreme Court considered a case involving a police inspector who committed suicide after substantial increases in workload and long periods of consecutive work.

The Court reaffirmed that an employer has a duty of care to ensure that a worker's physical and mental health is not impaired by excessive accumulation of fatigue or psychological burden. It also stressed that the circumstances of the work must be considered comprehensively.

Relevance:
Where an injury or occupational illness results from workload, fatigue or psychological burden, the employer should not restrict its investigation to the immediate physical event.

3. Asbestos Construction Workers Case — Supreme Court, 17 May 2021

2018 (Ju) No. 1447

The Supreme Court examined occupational asbestos exposure among construction workers and held, under the circumstances of the case, that the State's failure to exercise regulatory authority under the Industrial Safety and Health Act could give rise to State liability.

The judgment also examined the obligations of manufacturers and the need for adequate warnings concerning asbestos risks.

Relevance:
Workplace injury can involve occupational disease developing over many years rather than an immediately observable accident. Employers therefore need systems capable of identifying and documenting occupational exposure.

4. Asbestos Health-Hazard Case — Supreme Court, 2021

The asbestos litigation demonstrates that workplace harm can arise from long-term exposure, not merely from a single accident.

The Supreme Court considered matters including the employer's obligations concerning hazardous substances, protective equipment, warnings and workplace controls.

Relevance:
An accident-reporting system should connect individual injury records with broader occupational-health information where repeated exposure or similar injuries are identified.

5. Mitsubishi Fuso Hub Accident Case — Supreme Court, 8 February 2012

2009 (A) No. 359

This criminal case concerned truck-wheel hub failures that resulted in a fatal accident and injuries to pedestrians.

The Supreme Court held that persons responsible for quality assurance could have a duty to take necessary measures, including improvement measures and recalls, where they could recognise the risk of serious accidents and had the authority to respond.

Relevance:
The case illustrates a broader principle important to workplace safety: once responsible personnel possess significant safety information, merely recording accidents without taking preventive action may be insufficient.

6. Minamata Disease Case — Supreme Court, 15 October 2004

2001 (O) No. 1194

Although this was not a conventional workplace accident case, the Supreme Court considered the consequences of regulatory failure where serious health hazards were known or reasonably recognisable.

The Court found State liability under the State Redress Act in circumstances where regulatory authorities failed to exercise available powers to prevent the spread of serious health hazards.

Relevance:
The case demonstrates the broader Japanese legal significance of known risks, regulatory powers and preventive action—principles that are relevant when analysing occupational health and safety systems.

13. Legal consequences of failure to report

Failure to report, or deliberately submitting a false report, can expose the responsible employer to legal consequences.

Under the Industrial Safety and Health Act framework, failure to make required reports or making false reports can constitute an offence subject to criminal penalties. MHLW specifically states that “労災かくし” is a crime.

Potential consequences include:

• criminal penalties;
• Labour Standards Inspection Office investigation;
• corrective or administrative measures;
• workers' compensation proceedings;
• civil damages claims;
• increased regulatory scrutiny;
• reputational consequences; and
• evidence of inadequate safety governance.

14. Practical HR compliance procedure

A Japanese employer can structure its workplace-injury process as follows:

Step 1 — Immediate medical response
Provide first aid and arrange emergency medical treatment.

Step 2 — Secure the workplace
Prevent further injury and preserve the accident scene.

Step 3 — Notify management
Immediately notify HR, safety personnel and responsible management.

Step 4 — Record facts
Document time, location, activity, equipment, witnesses and circumstances.

Step 5 — Determine reporting category
Establish whether the case involves death, four or more days' absence, or less than four days' absence.

Step 6 — Submit statutory report
Use the prescribed electronic reporting procedure to the competent Labour Standards Inspection Office.

Step 7 — Investigate cause
Identify immediate, underlying and organisational causes.

Step 8 — Correct the hazard
Repair, replace, redesign, retrain or reorganise as necessary.

Step 9 — Check for similar risks
Examine other locations, shifts, machines and employees.

Step 10 — Preserve records
Maintain the accident report and supporting evidence in accordance with applicable retention requirements.

Step 11 — Review recurrence
Monitor whether corrective measures actually eliminate or reduce the risk.

15. Key compliance principles

Conclusion

In Japan, reporting a workplace injury is not merely an HR administrative formality. Article 97 of the Ordinance on Industrial Safety and Health establishes a statutory reporting mechanism designed to place occupational accidents before the Labour Standards Inspection Office and support prevention of recurrence.

The case law additionally demonstrates a broader principle: employers and responsible managers may have duties to identify foreseeable occupational risks, protect workers, respond to known dangers and take preventive measures. The Dentsu case, recent police-inspector decision, asbestos litigation and other safety cases illustrate how courts examine the relationship between knowledge of risk, managerial responsibility, preventive action and resulting harm.

For compliance purposes, the safest approach is therefore to treat every potentially reportable workplace injury as requiring prompt medical assistance, evidence preservation, factual investigation, statutory reporting, root-cause analysis and documented corrective action.