On June 1, 2025, Japan's Industrial Safety and Health Regulation was amended (MHLW Ministerial Ordinance No. 59) to make workplace heatstroke prevention legally mandatory. The amendment responds to 20-30 annual heatstroke deaths and ~1,000 serious injuries in workplaces, particularly in construction, agriculture, and outdoor delivery sectors.
Application Criteria (Industrial Safety and Health Regulation Art. 612-2)
Workplaces are subject to mandatory measures when:
| Criterion | Threshold |
|---|---|
| WBGT-based | WBGT exceeds 28°C |
| Temperature-based | Air temperature exceeds 31°C |
| Work duration | 1+ hour continuous or 4+ hours per day |
WBGT (Wet Bulb Globe Temperature) is the international standard for heatstroke risk.
Affected Industries
All industries are subject, but high-risk sectors include construction, agriculture, transport/warehousing, manufacturing (steel, casting, welding), security, and outdoor cleaning.
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Try for free →Three Mandatory Obligations
1. Reporting System (Art. 612-2(1))
Employers must establish a clear path for workers to report heatstroke symptoms — to site managers and health & safety officers — with documented communication channels and record formats.
2. Rest Area Facilities (Art. 612-2(2))
Required facilities include cooled/air-conditioned rest spaces, cold drinking water, ice and cooling towels, and outdoor shade.
3. Response When Heatstroke Occurs (Art. 612-2(3))
Required response: stop work, move to cool area, cool the body (neck, armpits, groin), provide water and salt, call emergency services in severe cases, transport to hospital, notify family.
Penalties
Violations carry up to 6 months imprisonment or ¥500,000 fine (Industrial Safety and Health Act Art. 119). In case of injury or death, the employer may also face professional negligence resulting in injury or death (Criminal Code Art. 211) and civil damages for breach of safety care duty (Labor Contract Act Art. 5).
Court precedents in heatstroke death cases have awarded ¥30-50 million in damages.
Compliance Checklist
Employer: 1. ☐ Deploy WBGT meters at construction sites and outdoor workplaces (by June) 2. ☐ Develop heatstroke prevention manual and train workers 3. ☐ Secure rest areas (tents, cooled vehicles, air-conditioned break rooms) 4. ☐ Distribute cooling gear (cooling vests, fan-equipped work clothes) 5. ☐ Conduct emergency response drills (annually) 6. ☐ Health & safety committee heatstroke risk assessment 7. ☐ Consider adding heatstroke risk to health check protocols
Worker: 1. ☐ Report body condition changes to supervisor 2. ☐ Maintain hydration (250+ml/hour) 3. ☐ Wear hat and breathable work clothes 4. ☐ Manage prior night's sleep, alcohol, and overall condition 5. ☐ Disclose chronic conditions to supervisor and occupational physician
Heatstroke Workplace Deaths
| Year | Deaths | Serious injuries |
|---|---|---|
| 2021 | 20 | 547 |
| 2022 | 30 | 827 |
| 2023 | 28 | 880 |
| 2024 | 31 | 1,045 |
Construction and transport sectors account for the majority — providing the statistical basis for the amendment.
Civil Liability
Article 5 of the Labor Contract Act imposes a safety care duty on employers. Heatstroke prevention violations constitute textbook safety care breaches and ground civil damages claims.
Damage calculation in heatstroke death cases: 1. Lost earnings (present value of future income) 2. Pain and suffering damages (decedent and family) 3. Funeral expenses (~¥1.5 million) 4. Attorney fees (~10% of damages)
Total typically ¥30-50 million, with higher amounts for severe disability cases.
Conclusion
Japan's June 1, 2025 amendment makes workplace heatstroke prevention legally mandatory. Penalty risks (criminal: 6 months imprisonment; civil: ¥30 million+ damages) make compliance essential. By June: WBGT meters, rest areas, cooling equipment, written manual, and training drills.
For workplace safety violations, occupational injury claims, and safety care duty disputes, consult an attorney experienced in labor law.
